Tamilnadu State Board New Syllabus Samacheer Kalvi 11th Bio Zoology Guide Pdf Chapter 11 Chemical Coordination and Integration Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 11th Bio Zoology Guide Chapter Chapter 11 Chemical Coordination and Integration

11th Bio Zoology Guide Chemical Coordination and Integration Text Book Back Questions and Answers

Part I

Question 1.
The maintenance of a constant internal environment is referred as
a) Regulation
b) homeostasis
c) Co-ordination
d) hormonal control
Answer:
b) homeostasis

Question 2.
Which of the following are exclusive endocrine glands?
a) Thymus and testis
b) adrenal and ovary
c) parathyroid and adrenal
d) pancreas and parathyroid
Answer:
c) parathyroid and adrenal

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 3.
Which of the following hormone is not secreted under the influence of the pituitary gland?
a) thyroxine
b) insulin
c) oestrogen
d) glucocorticoids
Answer:
b) insulin

Question 4.
Spermatogenesis in mammalian testes is controlled by
a) Luteinising hormone
b) Follicle-stimulating Hormone
c) FSH and prolactin
d) GH and prolactin
Answer:
b) Follicle-stimulating Hormone

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 5.
Serum calcium level is regulated by
a) Thyroxine
b) FSH
c) Pancreas
d) Thyroid and parathyroid
Answer:
d) Thyroid and parathyroid

Question 6.
Iodised salt is essential to prevent
a) rickets
b) scurvy
c) goiter
d) acromegaly
Answer:
c) goiter

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 7.
Which of the following gland is related to immunity?
a) Pineal gland
b) adrenal gland
c) thymus
d) parathyroid gland
Answer:
c) thymus

Question 8.
Which of the following statement about sex hormones is correct?
a) Testosterone is produced by Leydig ceils under the influence of the luteinizing hormone
b) Progesterone is secreted by corpus luteum and softens pelvic ligaments during childbirth
c) Oestrogen is secreted by both sertoli cells and corpus luteum
d) Progesterone produced by corpus luteum is biologically different from the one produced by the placenta.
Answer:
a) Testosterone is produced by Leydig cells under the influence of luteinizing hormone

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 9.
Hypersecretion of GH in children leads to
a) Cretinism
b) Gigantism
c) Graves disease
d) Tetany
Answer:
b) Gigantism

Question 10.
A pregnant female delivers a baby who suffers from stunted growth, mental retardation, low intelligence quotient, and abnormal skin. This is the result of
a) Low secretion of growth hormone
b) Cancer of the thyroid gland
c) Over secretion of pars distalis
d) Deficiency of iodine in the diet
Answer:
a) Low secretion of growth hormone

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 11.
The structure which connects the hypothalamus with the anterior lobe of the pituitary gland is the
a) Dendrites of the neurohypophysis
b) Axons of neuro hypophysis
c) Bands of white fibers from the cerebellar region
d) Hypophysial portal system
Answer:
d) Hypophysial portal system

Question 12.
Comment on homeostasis.
Answer:

  • Maintenance of constant internal environment of the body by the different co-ordinating system.
  • The maintenance of the constant internal environment of the body is due to the functioning of the endocrine system and nervous system.
    Endocrine gland.

1. a) If the calcium level in the blood decreases the parathyroid gland secretes parathyroid hormones and increases the calcium level in the blood.
b) If there is more calcium in the blood the other hormone secreted by the parathyroid gland called calcitonin acts against the parathormone and reduces calcium level.

2. a) The adrenalin secreted by the adrenal gland in emergency increases heartbeat rate and blood pressure.
b) The other hormone secreted by the adrenal is nor-adrenalin which reduces heartbeat rate and blood pressure.

Nervous system:
1. a) The sympathetic nervous system at the time of shock induces tear glands to secrete tears,
b) The parasympathetic nerve at the time of shock and emotion reduces the tear secretion.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 13.
Which one of the following statement is correct
a) Calcitonin and thymosin are thyroid hormones
b) Pepsin and prolactin are secreted in the stomach
c) Secretin and rhodopsin are polypeptide hormones
d) Cortisol and aldosterone are steroid hormones
Answer:
d) Cortisol and aldosterone are steroid hormones

Question 14.
Which of the given option shows all wrong statements for thyroid gland Statements?
i) It inhibits the process of RBC formation
ii) It helps in the maintenance of water and electrolytes
iii) It’s more secretion can reduce blood pressure
iv) It stimulates osteoblast
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iv)
(d) (i) and (iii)
Answer:
(d) (i) and (iii)

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 15.
Hormones are known as a chemical messengers. Justify.
Answer:
Hormones are released into the bloodstream and circulated as chemical signals. These act specifically on certain organs or tissues called target organs or tissues. These speed up or slow down or alter the activity of target tissues or organs. Hence they are known as chemical messengers.

Question 16.
Write the role of t-oestrogen in ovulation.
Answer:

  • Oestrogen hormones promote the growth of the ovarian follicle
  • While the follicles are growing it secretes the hormone oestrogen which in turn promotes the ovum to develop.
  • The shedding up of ovum at the Luteal phase takes place by the influence of the Luteinizing hormone.

Question 17.
Comment on Acini of the thyroid gland.
Answer:
The thyroid gland is a bilobed endocrine gland. Each lobe is made up of many lobules. The lobules consist of follicles called acini. Each acinus is lined with glandular, cuboidal, or squamous epithelial cells. The lumen of the acinus is filled with colloid, a thick glycoprotein mixture consisting of thyroglobulin molecules.

Question 18.
Write the causes for diabetes mellitus and diabetes insipidus.
Answer:

  • Diabetes emeritus: If the insulin is not secreted sufficiently the liver and muscles are unable to convert the glucose into glycogen. As a result, more glucose enters into the bloodstream raising the blood sugar level leads to diabetes mellitus.
  • Diabetes Insipidus: The hormone antidiuretic hormone is secreted by the neurohypophysis, which promotes reabsorption of water and thus reduces the loss of water through urine ADH deficiency induces the production of large amounts of urine leads to diabetes insipidus.

Question 19.
Specify the symptoms of acromegaly.
Answer:
Acromegaly is caused due to excessive secretion of growth hormone in adults. The symptoms of acromegaly are an overgrowth of hand bones, feet bones, jawbones malfunctioning of gonads. enlargement of viscera, tongue, lungs, heart, liver, spleen, and endocrine glands like thyroid, or adrenal glands.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 20.
Write the symptoms of cretinism.
Answer:
Decreased secretion of the thyroid (Hypothyroidism) causes cretinism. The cretins show retarded skeletal growth, absence of sexual maturity retarded mental ability thick wrinkled skin, protruded enlarged tongue bloated face, thick and short limbs occurs. The other symptoms are low BMR slow pulse rate, subnormal body temperature, and elevated blood cholesterol level.

Question 21.
Briefly explain the structure of the thyroid gland.
Answer:
The thyroid gland is butterfly-shaped, bilobed situated below the larynx on each side of the upper trachea. The two lobes are connected by a median tissue mass called isthmus. Each lobe is made up of many lobules. The lobules consist of follicles called acini. Each acinus is lined with glandular, cuboidal, or squamous epithelial cells.

The lumen of acini is filled with colloid, a thick glycoprotein mixture consisting of thyroglobulin molecules. The thyroid gland secretes Tri-iodothyronine (T,) and tetra-iodothyronine (T4) or thyroxine hormones. These are concerned with metabolism.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 1

Question 22.
Name the layers of adrenal cortex and mention their secretions.
Answer:

  • The adrenal cortex has three layers namely Zona glomerulosa, Zona fasciculate and Zona reticulate. Zona glomerulosa which constitutes 15% of cortex is a thin outer layer secretes minerals corticoids
  • Zona fasciculate the middle widest layer constitutes 75% cortex and secretes gluco corticosteroids such as cortisol, corticosterone and small amount of adrenal androgen and oestrogen.
  • Zona reticulata an inner layer of adrenal cortex constitute about 19% of cortex and secretes adrenal androgen and small amount of estrogen and glucocorticoids.

Question 23.
Differentiate hyperglycemia from hypoglycemia.
Answer:
Hyper glycemia:
Hyperglycemia is condition in which there is increased blood glucose level, it may be due to the reduced secretion of insulin.

Hypo glycemia:
Hypoglycemia is a condition in which the blood glucose level decreases. It may be due to increased secretion of insulin there by reducing blood glucose level.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 24.
Write the functions of (CCK)- Cholecystokinin.
Answer:
CholecystokininCholecystokinin is secreted by duodenum in response to the presence of fat and acid in the diet. It acts on the gall bladder to release bile into duodenum and stimulates the secretion of pancreatic enzymes and its discharge.

Question 25.
Growth hormone is important for normal growth. Justify the statement.
Answer:
Growth hormone promotes growth of all the tissues and metabolic process of the cell. The growth hormone stimulates the growth in the following ways

  • It influences the metabolism of carbohydrate proteins and lipids.
  • It increases the rate of protein biosynthesis.
  • It stimulates cartilage formation of condrogenesis.
  • It stimulates bone formation osteogenesis.
  • It helps in the retention of minerals like nitrogen, potassium, phosphorous sodium in the body.
  • It increases the release of fatty acid from adipose tissue.
  • It decreases the rate of glucose utilization for energy by the cell, by which it conserves glucose for glucose dependent tissues such as the brain.

Question 26.
Pineal gland is an endocrine gland, write its role.
Answer:
The pineal gland or epiphysis cerebri or conarium is located behind the third ventricle of brain. It is formed of paranchymal cells and interstitial cells. It secretes the hormone, melatonin.

It plays a central role in the regulation of circadian rhythm of our body and maintains normal sleep-wake cycle. It also regulates the timing of sexual maturation of gonads. It also influences metabolism, pigmentation, menstrual cycle and defence mechanism of our body.

Question 27.
Comment on the functions of adrenalin.
Answer:

  • Adrenalin increases liver glycogen breakdown into glucose and increases the release of fatty acids from fat cells.
  • During emergency it increases heart beat rate and blood pressure.
  • It stimulates the smooth muscles of cutaneous and visceral arteries to decrease blood flow.
  • It increases blood flow to the skeletal muscles there by increases the metabolic rate of skeletal muscles cardiac muscles and nervous tissues.

Question 28.
Predict the effects of removal of Pancreas from the human body.
Answer:
Pancreas is both exocrine and endocrine gland. It is located just below the stomach as a leaf like structure. It secretes digestive enzymes and hormones like insulin and glucogon.

The digestive enzymes digest carbohydrates, proteins and fats. Insulin and glucose regulate blood sugar level. If pancreas is removed from the body, digestion and main’taince of blood sugar level gets afftected.

Question 29.
Enumerate the role of kidney as an endocrine gland.
Answer:

  • Kidney is a partial endocrine gland. Kidney secretes hormones such as renin, erythropoietin and calcitriol.
  • Renin is secreted by Juxta glomerular cells (JG) which increase blood pressure when angiotensin is formed in blood.
  • Erythropoietin is also secreted by JGA cells of the kidney and stimulates the formation of RBC in bone marrow known as erythropoiesis.
  • Calcitriol is secreated by proximal tubules of nephron, it is an active form of vitamin D3 which promotes calcium and phosphorus absorption from intestine and accelerates bone formation.

Part – II.

11th Bio Zoology Guide Chemical Coordination and Integration Additional Important Questions and Answers

I. Choose The Correct Answer

Question 1.
Where is hormones released ifito?
a) Mouth
b) Blood
c) Digestive system
d) Kidney
Answer:
b) Blood

Question 2.
Find out the endocrine glands from the following.
a) Sebaceous gland
b) Sweat glands
c) Salivary glands
d) Thyroid gland
Answer:
d) Thyroid gland

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 3.
Which is called as master endocrine glands?
a) Hypothalamus
b) Pituitary gland
c) Thyroid gland
d) Thymus
Answer:
b) Pituitary gland

Question 4.
Where is pituitary situated?
a) On the ethmoid bone
b) On sella turcica
c) On the foramen of Monro
d) On the Rathkes packet
Answer:
b) On sella turcica

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 5.
The retention of nitrogen is due to this hormone.
a) TSH
b) GH
c) FSH
d) ACTH
Answer:
b) GH

Question 6.
Find out the wrong statement related with growth hormone.
1. a) It stimulates cartilage formation
2. b) It releases the fattyacid from adipose tissue
3. c) It increases the glucose utilization in the cells
4. d) It stimulates the carbohydrate synthesis
Answer:
4. d) It stimulates the carbohydrate synthesis

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 7.
A male child is born to a parents as he grown if FSH and LH is not properly secreted what happens to the male child.
a) He grows as a normal male child
b) He grows and he shows stunted growth
c) Secondary sexual characters are not developed properly
d) He grows as a mentally depressed male
Answer:
c) Secondary sexual characters are not developed properly

Question 8.
These hormones are collectively known as Gonodotropins?
a) Oxytocin and ADH
b) Oestrogen and Progestron
c) Testosteron and androgens
d) FSH and LH
Answer:
d) FSH and LH

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 9.
The day and night rhythm is controlled by this hormone.
a) Melonocytes
b) Melanin
c) Melotonin
d) Thyroxine
Answer:
c) Melotonin

Question 10.
Prabhu is working in a MNC Company. He has to do night shift once in every fifteen days.
Aftern a few years he is suffering from sleeplessness (in somnia) What may be the cause of his problem.
a) It may be becauses of his nature of work
b) More work pressure
c) The sleepwake cycle is disturbed due to the irregular synthesis of melotonin hormone
d) Due to the metabolic disturbances
Answer:
c) The sleepwake cycle is disturbed due to the irregular synthesis of melotonin hormone

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 11.
Name the structure that connects the lobes of thyroid gland?
a) Acinus
b) Ischium
c) Isthmus
d) bridge tissue
Answer:
c) Isthmus

Question 12.
Name the element helps in the synthesis of thyroxine.
a) Iron
b) Calcium
c) Iodine
d) Sodium
Answer:
c) Iodine

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 13.
Assertion: The Oxyphil cells of parathyroid secrete parathormone
Reason: The chief cells of parathyroid regulates the synthesis of parathormone
a) Assertion and Reason are correct
b) Assertion incorrect and reason is wrong
c) The assertion is true. The reason is false
d) Both the assertion and reason are false.
Answer:
d) Both the assertion and reason are false.

Question 14.
Which of the functional features of hormone is not correctly matched with its description?
a) Thyroid gland hormones often called the major metabolic hormones.
b) Thyro calcitonin increases the blood calcium level
c) The adrenalin is the emergency hormone.
d) The functions of oxyphil cells are not known.
Answer:
b) Thyro calcitonin increases the blood calcium level

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 15.
Which of the following option shows the with its action matched hormones
(given in column I) (given in column II)

Column I Column II
A Pituitary i) Partial endocrine gland
B Thyroid ii) Secretes steroid hormone oestrogen
C Ovary iii) Thyroxine regulates basal metabolic rate
D Thymus iv) Anterior lobe of pituitary originate from Rathke’s pouch

a) A – ii; B – iv; C – i; D – iii
b) A – iv ; B – iii; C – ii; D – i
c) A – iii; B – ii; C – iv; D – i
d) A – iv; B – i; C – iii; D – ii
Answer:
b) A – iv ; B – iii; C – ii; D – i

Question 16.
These are known as supra-renal glands.
a) Thymus gland
b) Pancreas
c) Adrenal gland
d) Ovary
Answer:
c) Adrenal gland

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 17.
Find out the hormone which are catecholamines.
a) Thyroxine
b) Insulin
c) Adrenalin
d) Glucagon
Answer:
c) Adrenalin

Question 18.
Why there is an accumulation of ketone bodies in blood of diabetic melitus patients?
a) due to the excessive consumption of liquids
b) break down of fat in to glucose
c) conversion of glucose from protein
c) due to excessive in take of food
Answer:
b) break down of fat in to glucose

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 19.
This hormone promotes the activation of Vitamin D thus by absorbing calcium?
a) Calcitonin
b) Thymosin
c) Parathormone
d) Thyroxine
Answer:
c) Parathormone

Question 20.
Which part of pancreas is act as a exocrine gland?
a) Globules
b) islets of Langerhans
c) Acinus
d) Globlets
Answer:
c) Acinus

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 21.
Name the cells that secrete somatostatin
a) a cells
b) b cells
c) Lampda cells
d) delta cells
Answer:
d) delta cells

Question 22.
Why is insulin tablet not advisable for chronic diabetic mellitus patients?
a) It takes more time to act
b) The insulin find it difficult to reach the substrate
c) Insulin is easily digested by the digestive enzymes
d) The insulin is not a effective one.
Answer:
c) Insulin is easily digested by the digestive enzymes

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 23.
This hormone is involved in the cyclic changes of menstruation.
a) Testosterone
b) Pitocin
c) Oestrogen
d) Progesterone
Answer:
c) Oestrogen

Question 24.
Contraction of uterus leads to miscarriages in a pregnant womens.
What would be administered to evacuate the embryo?
a) ADH
b) Vasopressin
c) Androgen
d) Oxytocin
Answer:
d) Oxytocin

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 25.
In the case of thyrotecdomic patients what is advisable to given along with the thyroxine?
a) Insulin
b) Thyroglobulin
c) Parathormone
d) Adrenalin
Answer:
c) Parathormone

Question 26.
If a doctor finds a high level of atrial natriuretic factor in the blood of a patient what he will suspect?
a) A patient is suffering from in sufficient oxygen supply
b) A patient will have a heart attack due to high blood pressure
c) Suspecting depression problem
d) Many develop thrombosis
Answer:
b) A patient will have a heart attack due to high blood pressure

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 27.
Name the hormone that stimulates the synthesis of HCl.
a) Enterokinase
b) Pepsinogen
c) Gastrin
d) Secretin
Answer:
c) Gastrin

Question 28.
What is the other name for type I diabetes?
a) Insulin dependent diabetes
b) Non-insulin dependent diabetes
c) Sensitive diabetes
d) Dependent types
Answer:
a) Insulin dependent diabetes

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 29.
Which is called as second messenger.
a) Receptor cells
b) CAMP
c) Adenylate
d) Substrate
Answer:
b) CAMP

Question 30.
In the following diagram what are the parts A, B, C and D representing?
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 2
I) A) Pineal body B) Anterior tube C) Capillary bed D) Infundibulum
II) A) Hypophyseal vein B) Optic chiasma C) Endocrine cells D) Artery
III) A) Infundibuim B) Posterior C) Hypophyseal vein D) Endocrine cells
IV) A) Endocrine cells B) Infundibulum C) Paradisaical D) Pineal body
Answer:
III) A) Infundibuim B) Posterior C) Hypophyseal vein D) Endocrine cells

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 31.
Find out the true and false statements from the following and on that basis find the correct answer.
i) ADH causes blood vessels to dialate
ii) The ‘c’ cells of thyroid gland secretes calcitonin
iii) Zona fasciculate secretes cortisol
iv) Minerals corticoids regulate water balance
i) a) True b) False c) True
ii) a) False b) True c) False
iii) a) False b) True c) False
iv) a) False b) False c) True
Answer:
iv) a) False b) False c) True

Question 32.
Which part interlinks both the nervous system and endocrine system?
a) Receptor molecules
b) Target tissue
c) Hypothalamus
d) Infundibulum
Answer:
c) Hypothalamus

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 33.
Which of the following disease is not caused by iodine or thyroxine deficiency?
a) Sporodic goitre
b) Exophthalmic goitre
c) Simple goitre
d) Myxodema
Answer:
a) Sporodic goitre

Question 34.
Which is the correct location of the receptors of the hormones?
a) Extracellular matrix
b) Blood
c) Plasma membrane
d) Nucleus
Answer:
c) Plasma membrane

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 35.
The primary target of the hormones of hypothalamus is
a) pineal gland
b) thymus
c) testis
d) pituitary
Answer:
d) pituitary

Question 36.
Functionally the adenohypophysis of pituitary gland includes
a) anterior lobe
b) Posterior lobe
c) intermediate lobe
d) both (a) and (c)
Answer:
d) both (a) and (c)

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 37.
An outgrowth of hypothalamus from the base of the brain develops into
a) pars nervosa
b) pars intermedia
c) pars distalis
d) pars intermedia
Answer:
a) pars nervosa

Question 38.
The hormone secreted by neurohypophysis is
a) ACTH
b) ADH
c) GH
d) TSH
Answer:
b) ADH

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 39.
Among the following hormones which is the peptide hormone.
a) GH
b) TSH
c) FSH
d) LH
Answer:
a) GH

Question 40.
Among the following which is not a glycoprotein hormone.
a) TSH
b) LTH
c) LH
d) FSH
Answer:
b) LTH

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 41.
Find out the protein hormone from the following.
a) LTH
b) FSH
c) TSH
d) ACTH
Answer:
a) LTH

Question 42.
Which is the pituitary hormone that is present in other vertebrates?
a) MSH
b) ACTH
c) TSH
d) GH
Answer:
a) MSH

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 43.
Find out the wrong statement about vasopressin or ADH
a) It promotes re-absorption of water and electrolytes by distal tubules of nephron.
b) Causes constriction of blood vessels
c) It stimulates vigorous contraction of smooth muscles of uterus during child birth
d) It is a peptide hormone
Answer:
c) It stimulates vigorous contraction of smooth muscles of uterus during child birth

Question 44.
The growth hormone releasing hormone stimulates the
a) Thymus to release the hormone
b) Pituitary for synthesis and release of growth hormone
c) Testis to release gonadotropin
d) Adrenal to release growth hormone
Answer:
b) Pituitary for synthesis and release of growth hormone

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 45.
Posterior pituitary secretion is controlled by
a) hypothalamic hypophyseal portal blood vessel
b) neuro endocrine gland
c) hypophysis
d) hypothalamic hypophyseal axis
Answer:
d) hypothalamic hypophyseal axis

Assertion and Reason:- Directions: In the following questions a statement of Assertion is followed by a statement of reason. Mark the correct choice as;
a) If both Assertion and reason are true and reason is the correct explanation of assertion
b) If both Assertion and reason and true but reason is not the correct explanation of Assertion.
c) If assertion is true but reason is false
d) If both Assertion and reason are false

Question 46.
Assertion: Adrenalin nor-adrenalin, melatonin and thyroid hormones are proteins
Reason: Derived from cholesterol mostly water soluble
Answer:
d) If both Assertion and reason are false

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 47.
Assertion: Growth hormone stimulates chondrogenesis and osteogenesis
Reason: Growth hormones promote growth of all tissues and metabolic process of the body.
Answer:
a) If both Assertion and reason are true and reason is the correct explanation of assertion

Question 48.
Assertion: Adrenal medulla hormones are referred as 3F hormones fight, flight and hormones.
Reason: During emergency it increases heart beat rate and blood pressure
Answer:
a) If both Assertion and reason are true and reason is the correct explanation of assertion

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 49.
Assertion: The effects of aldosterone, oestrogen FSH are long lived as they alter the amount of m- RNA and protein in a cell
Reason: The action of cAMP are terminated by phosphodiesterases
Answer:
b) If both Assertion and reason and true but reason is not the correct explanation of Assertion.

Question 50.
Assertion: The immunity of old age people, becomes week and causes sickness.
Reason: Due to degeneration of pineal gland thymosin level decreases
Answer:
c) If assertion is true but reason is false

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 51.
Assertion: JGA cells of the kidney stimulates erythropoiesis or formation of RBC
Reason: JGA cells also secrete Erythropoietin
Answer:
a) If both Assertion and reason are true and reason is the correct explanation of assertion

Question 52.
Assertion: Diabetes inspidus is marked by production of large amount of urine.
Reason: Hypo secretion of ADH leads to a condition of reduced water absorption. Thus the urine becomes diluted without sugar or glucose
Answer:
a) If both Assertion and reason are true and reason is the correct explanation of assertion

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 53.
The Luteinizing hormone in males is
a) Testosterone
b) ICSH
c) FSH
d) LTH
Answer:
b) ICSH

Question 54.
The cells that secrete parathyroid hormone is knows as
a) chief cells
b) oxyphil cells
c) goblet
d) both b and c cells
Answer:
a) chief cells

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 55.
Find out the correct statement about pineal gland.
a) Stimulates the production and release of sperms.
b) Increases blood pressure.
c) It plays a central role and the regulation of circadian rhythm of our body and maintains the normal sleep wake cycle.
d) It is about 1cm in diameter and 0.5gm.
Answer:
c) It plays a central role and the regulation of circadian rhythm of our body and maintains the normal sleep wake cycle.

Question 56.
The BMR is regulated by
a) Parathormone
b) Thyrocalcitonin
c) Adrenalin
d) Thyroxine
Answer:
d) Thyroxine

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 57.
The primary function of thymus gland is
a) regulation of body temperature
b) regulation of body growth
c) immunological functions
d) Secretion of thyrotropin
Answer:
c) immunological functions

Question 58.
A hormone secreted by adrenal gland and called life-saving hormone is
a) adrenaline
b) cortisone
c) aldosterone
d) Cortisol
Answer:
d) Cortisol

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 59.
Which of the following condition is not linked to a deficiency of thyroid hormone?
a) cretinism
b) goitre
c) Myxoedema
d) Exophthalmia
Answer:
d) Exophthalmia

Question 60.
Androgens are sex corticoids secreted from
a) Zona reticulate
b) Adrenal medulla
c) Zona glomerulosa
d) Acini
Answer:
a) Zona reticulate

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 61.
A gland which is well developed in newborn child and produce lymphocytes
a) Thyroid gland
b) Thymus
c) Parathyroid gland
d) Pineal gland
Answer:
b) Thymus

Question 62.
Which one reduces the blood calcium level and shows an opposite effect to parathormone?
a) ADH
b) Insulin
c) Thyrocalcitonin
d) Thyroxine
Answer:
c) Thyrocalcitonin

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 63.
Secretion of HCl and pepsinogen is controlled by
a) Cholecystokinin
b) Gastrin
c) Calcitriol
d) Renin
Answer:
b) Gastrin

Question 64.
A man has an IQ equivalent to that of a boy 5 years old this is due to the deficiency of which hormone?
a) Thyroxine
b) Adrenaline
c) Aldosterone
d) Somatotropin
Answer:
a) Thyroxine

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 65.
Which of the following option shows the correct matching of disorder’s and causes.
A) Addison’s disease -(i) Hypo secretion of thyroid
B) Cushing’s syndrome – (ii) Hyper secretion of parathyroid hormone
C) Softening of bone – (iii) Hypo secretion of gluco corticoids
D) Gull’s disease (in adults) – (iv) Excess secretion of cortisol
Codes:
a) A – (ii); B – (i); C – (iii); D – (iv)
b) A – (iii); B – (iv); C – (ii); D – (i)
c) A – (iii); B – (ii); C – (i); D – (iv)
d) A – (iv); B – (iii); C – (iv); D – (ii)
Answer:
b) A – (iii); B – (iv); C – (ii); D – (i)

Question 66.
A person is having problems with calcium and phosphorous metabolism in his body.
Which one of the following glands may not be functioning.
a) Parathyroid
c) Pancreas
b) Parotid
d) Thyroid
Answer:
a) Parathyroid

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 67.
Presence of fat and acid in the diet induces the secretion of
a) Gastrin
b) Secretion
c) Cholecystokinin
d) Calcitrol
Answer:
c) Cholecystokinin

Question 68.
Which is an amino acid derivative hormone?
a) Epinephrine
c) Progesterone
b) Oestrogen
d) Relaxin
Answer:
a) Epinephrine

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 69.
Which of the following is a mineralococticoid?
a) Testosterone
b) Cortisol
c) Adrenalin
d) Aldosterone
Answer:
d) Aldosterone

Question 70.
Which hormone increases the rate of protein biosynthesis chondrogenesis and osteogenesis and helps in the retention of minerals?
a) Prolactin
b) Somatotrophic hormone
c) Thyrotropin
d) Glucagon
Answer:
b) Somatotrophic hormone

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 71.
The male sex hormones are secreted by
a) Zona glomerulosa
b) Fat cells
c) Lay-dig cells
d) Acini
Answer:
c) Lay-dig cells

Question 72.
Which of the following pituitary hormone is secreted without the involvement of a releasing hormone?
a) Thyrotropin
b) Follicle stimulating hormone
c) Oxytocin
d) Prolactin
Answer:
c) Oxytocin

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 73.
Match the following columns.

Column I Column II
A Melatonin 1. T-lymphocyte formation
B Thymus 2. Formation of RBC
C Insulin 3. Sleep wake cycle
D Trythropoietin 4. Hypoglycemic hormone

Code:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 3
Answer:
b) A -3,B-1,C-4,D-2

Question 74.
Which hormones can easily pass through the cell membrane and bind to their receptors and alter gene function?
a) Peptide hormones
b) Amino acid derived hormones
c) Neuro hormones
d) Steroid hormones
Answer:
d) Steroid hormones

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 75.
The hormone which helps to find out conception is
a) FSH
b) Oestrogen
c) HCG
d) LH
Answer:
c) HCG

Question 76.
Gigantism and Acromegaly are due to
a) Hypothyroidism
b) Hyperthyroidism
c) Hypopituitarism
d) Hyper pitituitarism
Answer:
d) Hyper pitituitarism

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 77.
After performing the functions in the target organs how hormones are inactivated and excreted?
a) By intestine
b) By lungs and skin
c) By liver and Kidney
d) Both a and b
Answer:
c) By liver and Kidney

Question 78.
The half life period of insulin is
a) 6 minutes
b) 8 minutes
c) 15 minutes
d) 7 minutes
Answer:
a) 6 minutes

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 79.
The time taken by insulin to be cleared from circulation is
a) 10 -20 minutes
b) 10-15 minutes
c) 5 – 10 minutes
d) 2-10 minutes
Answer:
b) 10-15 minutes

(2 Marks)

II. Very Short Answer.

Question 1.
What is the causes of bone cyst formation?
Answer:
Hyper para thyrodism causes demineralisation of bone causes bone cyst makes the bone fragile and soft.

Question 2.
Why is the hypothalamus considered a neuroendocrine gland?
Answer:
The hypothalamus alone with its neural function produces hormones. Hence it is considered a neuroendocrine gland.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 3.
What is the meaning of the word hormone?
Answer:
Hormone means to excite.

Question 4.
Write on the origin of the pituitary gland?
Answer:
The anterior lobe of the pituitary gland originates from the embryonic invagination of the pharyngeal epithelium called Rathke’s pouch. The posterior lobe originates from the base of the brain as an outgrowth of the hypothalamus.

Question 5.
What is meant by Homeostasis?
Answer:
Maintenance of constant internal environment of the body by the different co-ordinating system is homeostasis.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 6.
What is Pars nervosa?
Answer:
The neurohypophysis of the pituitary gland is known as pars nervosa.

Question 7.
Give example for partial endocrine glands.
Answer:
Pancreas, gastrointestinal tract epithelium kidney, heart gonads and placenta.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 8.
Write a paragraph on the Growth Hormone?
Answer:
Growth hormone (GH):
It is also known as somatotropic hormone (STH) or Somatotropin. It is a peptide hormone Growth hormone promotes the growth of all the tissues and metabolic processes of the body. It influences the metabolism of carbohydrates, proteins, and lipids and increases the rate of protein biosynthesis in the cells.

It stimulates chondrogenesis (cartilage formation), osteogenesis (bone formation) and helps in the retention of minerals like nitrogen, potassium, phosphorus, sodium, etc., in the body. GH increases the release of fatty acid from adipose tissue and decreases the rate of glucose utilization for energy by the cells. Thus it conserves glucose for glucose-dependent tissues, such as the brain.

Question 9.
Name the hormone of peptide nature?
Answer:
Insulin, glucagon and pituitary hormone which are water soluble.

Question 10.
What are steroid hormones.
Answer:
They are derived from cholesterol and are lipid soluble.
Ex. Cortisol aldosterone testosterone oestrogen progesterone.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 11.
What is the role of Follicle stimulating hormone in man?
Answer:
In male FSH acts on the germinal epithelium of semi niferous tubules and stimulates the production and release of sperms.

Question 12.
What is the function of LH in female?
Answer:
LH induces ovulation maintains the corpus luteum and promotes the synthesis and release of ovarian hormones.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 13.
Why there is a short life span for hormone-like insulin?
Answer:
Insulin hormone is usually short lived as it has to work through second messenger (cAMP) system.

Question 14.
Why the hormones steroid may be long-lived?
Answer:
The effect of steroid hormones are long lived as they alter the amount of mRNA and protein in a cell.
Ex. Aldosterone oestrogen FSH.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 15.
How do the hormones reach and act on the specific target organs?
Answer:

  • The hormones are released into the blood and circulated as chemical signals
  • The target organs contain receptor molecules either on the surface or within the cell.
  • The cells that contain the receptor molecules specific for the hormone are physiologically activated.
  • Where as other hormones that come in contact can not be activated.

Question 16.
Name the three zones which are present in the Adrenal gland.
Answer:

  1. Zona glomerulosa
  2. Zona fasciculata
  3. Zona reticularis

Question 17.
Differentiate amines and steroid hormones
Answer:

Amines Steroids
A. Small water soluble 1. Mostly lipid soluble
B. Derived from tyrosine or tryptophan 2. Derived from Cholesterol
C. Examples are Adrenalin Nor adrenalin, Melatonin and thyroid hormone 3. Examples are cortisol, aldosterone, testosterone, oestrogen and progesterone

Question 18.
Differentiate exocrine glands from endocrine glands.
Answer:

Exocrine glands Endocrine glands
1. They have ducts to carry their substances to the membrane surfaces 1. These lack ducts and so release their hormone to the surrounding tissue fluid
2. They secrete enzymes, saliva and sweat 2. Their secretions are collectively termed as hormones.
3. Eg. Salivary gland, Sweat gland and Gastric glands 3. Eg. Pituitary, Thyroid Pineal, Adrenal Parathyroid

Question 19.
How endocrine glands be classified based on their secretary function?
Answer:

  • Exclusive endocrine glands, e.g. Pituitary thyroid, Parathyroid, Pineal, Adrenal
  • Neuro endocrine gland – Hypothalamus
  • Partial endocrine glands, e.g. Pancreas, gastro intestinal tract epithelium, kidney, heart gonads and placenta – have endocrine tissues.

Question 20.
Pituitary gland is known as master endocrine glands. Justify the statement.
Answer:

  • Pituitary gland is known as master endocrine gland, but it is in turn controlled by the hypothalamus and so the statement may not be totally applicable.
  • The hypothalamus with its neuro secretary cells produces neuro transmitters which regulate the secretions of the pituitary.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 21.
Write about the location and dimension of pituitary gland.
Answer:

  • The pituitary gland is located in the bony cavity of the sphenoid bone the sella tursica at the base of brain so is also called hypothalamus cerebri
  • it is about one centimeter in diameter and 0.5gm in weight.

Question 22.
What is infundibulum?
Answer:
The pituitary gland is connected to the hypothalamic region of the brain by a stalk called infundibulum.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 23.
What is Rathke’s pouch?
Answer:
The anterior lobe of pituitary originates the embryonic invagination of pharyngeal epithelium called Rathke’s pouch.

Question 24.
Comment on MSH or Melanocyte stimulating hormone.
Answer:

  • In mammals role of Pass intermedia is insignificant.
  • In other vertebrates pass intermedia secretes melanocyte stimulating hormone or MSH.
  • It induces pigmentation in the skin.

Question 25.
What are the functions of pineal gland?
Answer:
In human, the pineal gland or epiphysis cerebri or conarium is located behind the third ventricle of brain and is formed of parenchymal cells and interstitial cells.

It secretes the hormone, melatonin, which plays a central role in the regulation of circadian rhythm of our body and maintains the normal sleep-wake cycle. It also regulates the timing of sexual maturation of gonads. In addition, melatonin also influences metabolism, pigmentation, menstrual cycle and defence mechanism of our body.

Question 26.
What are the other names of Luteotropic hormone?
Answer:

  1. Luteotropin
  2. Lactogenic hormone
  3. Proloctein
  4. Mammotropin

Question 27.
Name the hormones that their secretions are regulated by negative feed back mechanisms?
Answer:

  • Thyroid stimulating hormone TSH or Thyrotropin
  • Adreno corticotropic hormone or ACTH

Question 28.
Give the meanings of the word pituitary oxytocin and Hormone?
Answer:

  1. Pituitary means “to grow under”.
  2. Oxytocin means “quick birth”.
  3. Hormone means “to excite”.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 29.
Mention the importance of Luteotropic hormone in females?
Answer:
It stimulates milk secretion after the child birth.

Question 30.
Why prolactin is called luteotropic hormone?
Answer:

  • High prolactin secretion during lactation
  • Since it induces the corpus luteum hence named as luteotropic hormone.

Question 31.
Point out the role of oxytocin in females?
Answer:

  • It stimulates vigorous contraction of the smooth muscles of uterus during child birth.
  • Ejection of milk from the mammary glands after child birth.

Question 32.
Name the hormones that play a key role in milk secretion?
Answer:

  • Prolactin or lactogenic hormone or mammotropin or luteotropic hormone.
  • Oxytocin.

Question 33.
Name the hormone of pituitary that act on bloodvessels?
Answer:
The vasopressin causes constriction of blood vessels when released in large amount and in-creases blood pressure.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 34.
Which gland is located behind the third ventricle of brain?
Answer:
The pineal gland or epiphysis cerebri or conarium.

Question 35.
Which is the largest endocrine in the body and where it is located?
Answer:

  • The thyroid gland is the largest gland.
  • It is a bibbed gland located below the larynx on each side of upper trachea.

Question 36.
Name the hormones secreted by thyroid gland.
Answer:

  • Tri-iodo thyronine or T3
  • Tetra-iodo thyromne or T4 or Thyroxine
  • Thyrocalcitonin

Question 37.
What are parafollicular cells or ‘C’ cells?
Answer:

  • These are the cells in the thyroid gland.
  • These cells secrete a hormone called thyrocalcitonin.

Question 38.
What element is important for synthesis of thyroid hormones? In what quantity it is essential?
Answer:

  • Iodine is essential for the normal synthesis of thyroid hormones.
  • About 1m. a week of Iodine is required.

Question 39.
Mention the normal glucose level in prepandial and postpandial test for glucose?
Answer:

  1. Prepandial- 70-100 mg/dl (Fasting)
  2. Post pandial (About 2 hours after food) – 110 – 140mg/ dl.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 40.
Is it advisable to take alcohol frequently? What ill effects does it cause over the body?
Answer:

  • Alcohol consumption has widespread effect on endocrine system.
  • It impairs the regulation of blood glucose level.
  • More over it reduces the testosterone level
  • Increases the risk of osteoporosis.

Question 41.
What is the injection administered to diabetic patients? Why is it given as injection and not as oral pills?
Answer:

  • Humiline-N is administered to diabetic patients.
  • Human insulin is administered as injection and not by oral consumption.
  • The reason is if it is administered by oral consumption it may be digested by digestive enzymes.

Question 42.
What is sporadic goiter?
Answer:

  • It is a genetic disease
  • It is not caused by iodine or thyroxine deficiency.

Question 43.
Why laughing is good for health?
Answer:
It reduces the secretion of stress hormone, adrenalin and makes us to relax.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 44.
Define circadian rhythm.
Answer:
It is the 24-hour cycle of biological activities associated with natural periods of light and darkness.
Eg. Sleep wake cycle, body temperature, appetite etc.

(3 Marks)

III. Short Answer

Question 1.
What is simple goiter? What are its symptoms?
Answer:

  • Simple goitre is otherwise known as endemic goitre.
  • It is due to the hypo secretion of thyroxine.
  • The symptoms are Enlargement of thyroid gland, Fall in serum thyroxine level, Increased TSH secretion.

Question 2.
What is tetany?
Answer:

  • The hyposecretion of parathyroid hormones leads to a decrease in calcium level and increase in phosphate level, it causes.
  • convulsion in muscle, locking of jaws, increased heart beat rate increased body temperature muscular spasm lead to tetany.

Question 3.
What is cushing’s syndrome? What are its symptoms?
Answer:
The excess secretion of cortisol causes cushing’s syndrome. The symptoms are obesity of the face and trunk.

  1. Redness of face hand and feet.
  2. Thick skin.
  3. Excessive hair growth
  4. Loss of mineral from bone
  5. Systolic hypertension

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 4.
What is the cause of dwarfism?
Answer:
It is due to the hypo-secretion of growth hormone in children in which skeletal growth and sexual maturity is arrested. They attain a maximum height of 4 feet only.

Question 5.
What is Gigantism?
Answer:

  • Due to the hyper-secretion of growth hormone in children there is a over growth of skeletal
  • structure may occur up to 8 feet height. The visceral growth is not appropriate with that of limbs.

Question 6.
You are walking on the road, suddenly a man with a knife in his hand comes in front of you. What would be your reaction?
Answer:
I will get bimple goose due to the Surge of vasodielation on the arector pili muscle and though, i am very much frightened, i will fight with that man. i will get that energy by the action of the hormone adrenalin.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 7.
Why oxytocin is considered as quick or rapid birth?
Answer:
Oxytocin stimulates the contraction of the smooth muscles of uterus during child birth which helps in the expulsion of foetus, hence it is called as quick birth.

Question 8.
Why thymus is considered as a lymphoid organ?
Answer:
Thy lymphocytes that comes to thymus is educated to become immuno competent T lymphocytes and provides cell mediated immunity. Hence thymus is a lymphoid organ.

Question 9.
Why is gluco corticoids considered in the life saving activity?
Answer:
During the period of emergency the gluco corticoids stimulate the synthesis of glucose from lipid and protein by lipolysis and proteolysis and releases energy to meet that emergency situation.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 10.
Why cortisol works as a stress combat hormone?
Answer:

  • Cortisone involved in maintaining cardio vascular and kidney functions. It produces anti inflammatory reactions and suppresses the immune response, it stimulates the RBC production.
  • Hence it is known as stress combat hormone.

Question 11.
How do the hormones act in the target tissue?
Answer:

  • The hormones are released into the blood and circulated as chemical signals and act on specific target organs.
  • Hormones may speed up or slow down or alter the activity of the target organs.
  • The hormones secreted do not remain permanently in the blood.
  • They are converted by the liver into inactive compound and excreted by kidneys.

Question 12.
What is a limbic system?
Answer:

  • It is a collection of special structures located in the middle of the brain.
  • It is also known as paleo mammalian brain.
  • It controls emotions, behavior, motivation of long term memory and olfaction.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 13.
What are exocrine glands? Give examples
Answer:

  • The exocrine glands have ducts to carry their secretion to the membrane surfaces.
  • They secrete enzymes, saliva arid sweat.
  • Examples are salivary gland, gastric gland.

Question 14.
Write down the functions of hypothalamus.
Answer:

  1. Hypothalamic hormones control anterior pituitary secretion through hypothalamic hypophyseal portal blood vessel.
  2. The nerve signal produced by the hypothalamic hypophyseal axis control the posterior pituitary secretion.
  3. Hypothalamus maintains homeostasis.
  4. Blood pressure
  5. Body temperature.
  6. Cardio and fluid electrolyte balance of the
  7. As the part of limbic system it influences various emotional responses.

Question 15.
Draw the diagram of the hypothalamus and pituitary gland and label the following parts.
Answer:
A. Anterior lobe
B. Posterior lobe
C. Hypothalamus
D. Interior Hypophyseal artery
E. Endocrine cells
F. Hypophyseal vein
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 4

Question 16.
Draw the diagram of thyroid gland and label the following parts
Answer:
A Thyroid cartilage
B. Thyroid gland
C. Trachea
D.Isthumus
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 5

Question 17.
Draw the diagram of thyroid gland and label the following parts
A. Capsule
B. Cortex
C. Medulla
D. Blood Vessels
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 6

Question 18.
Explain the role of leuteinizing hormone (LH) in male and females.
Answer:

  • It is a glycoprotein hormone
  • It is also known as Interstitial cell stimulating hormone (ICSH) in males.
  • The ICSH hormones acts on the interstitial cells of testis to produce the male sex hormone testosterone.
  • In females along with FSH matures the ovarian follicles.
  • LH independently induces ovulation, maintains the corpus luteum and promotes synthesis and release of ovarian.
  • FSH and LH secretion starts only during pre pubertal period.
  • FSH and LH are collectively referred as gonadotropins.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 19.
Compare the structural difference of vasopressin and oxytocin. Vasopressin Oxytocin
Answer:

Exocrine glands Endocrine glands
1. Composed of a amino acids 1. Composed of a amino acids
2. Amino acid sequence is cysteine – tyrosine – Phenyl alanine – glutamine arspargine – cysteine – proline – argirune – glycine. 2. Amino acid sequence is – cysteine – tyrosine –
Isoleucine – Glutamine – aspargine – cysteine –
proline – leucine – glycine.

Question 20.
How does the posterior lobe of the pituitary help in osmoregulation?
Answer:

  • ADH is a peptide hormone
  • It promotes absorption of water and electrolytes by distal tubules of nephron and there by reduces loss of water through urine.
  • Hence it is called as anti diuretic hormone.
  • ADH deficiency causes Diabetes insipidus which induces the production of large amount of urine.
  • This is how it helps in osmoregulation.
  • ADH when released in large amount causes constriction of blood vessels and increases blood pressure.

Question 21.
Explain the role of melatonin in our body.
Answer:

  • It is secreted by pineal gland.
  • It plays a central role in the regulation of circadium rhythm of our body
  • Maintains the normal sleep wake cycle.
  • It also regulates the timing of sexual maturation of gonads.
  • In addition it also influences metabolism, pigmentation, menstrual cycle and defence mechanism of our body.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 22.
List out the role of thyroxine or tetra iodo thyronine (T4) in our body.
Answer:

  • It regulates the Basal Metabolic Rate (BMR) and body heat production.
  • It stimulates protein synthesis and promotes growth
  • It is essential for the development of skeletal and nervous system.
  • It plays an important role in maintaining blood pressure
  • It reduces serum cholesterol levels.
  • Optimum levels of thyroxine in the blood are necessary for gonadial functions.

Question 23.
Which hormone is called hypercalcemic hormone? Explain its role.
Answer:

  • The parathyroid hormone (PTH) is the hypercalcemic hormone.
  • It is a peptide hormone.
  • It involves in controlling the calcium and phosphate homeostasis.
  • The secretes or PTH is controlled by calcium level in the blood.
  • It increases the blood calcium level by stimulating osteoclasts to dissolve the bone matrix.
  • As a result calcium and phosphate are released into the blood.
  • PTH enhances the re-absorption of calcium and exertion of phosphates by the renal tubules.
  • It promotes activation of vitamin D to increase calcium absorption by intestinal mucosal cells.

Question 24.
Explain the role of heart as a partial endocrine gland.
Answer:
1. In the heart, cardiocytes on the atrial walls secretes an important peptide hormone called Atrial Natriuretic Factor (ANF)
2. When blood pressure is increased ANF is secreted and causes dilation of the blood vessels to reduce the blood pressure.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 25.
Is it good to take synthetic soft drinks? Why?
Answer:

  • It is not good to take synthetic soft drinks.
  • The branded soft drinks damage our endocrine system.
  • While consuming soft drinks the sugar level increases in blood. Which leads to elevated insulin secretion
    to reduce the blood glucose level.
  • The elevated insulin level diminishes immunity.
  • It causes obesity, cardio-vascular disorders etc.

Question 26.
The doctors avoid prescribing steroid tablets most often. Why?
Answer:
The abuse of steroids can cause serious health problems such as.

  • HighB.P.
  • Heart diseases.
  • Liver damage
  • Cancer
  • Stroke
  • Blood clotsa

Side effects such as

  1. Nausea
  2. V omiting
  3. Ligament and tendon injuries
  4. Head ache
  5. JointPain
  6. Muscle cramps
  7. Diarrhoea
  8. Sleep problem

Question 27.
if para-thyroid gland shows hyper-secretion. What will be the symptoms of this disorder?
Answer:

  • The excess secretion of parathyroid gland is known as hyperparathyroidism
  • Symptoms are Demineralisation of bone.
  • Cyst formation
  • Softening of bone
  • Loss of muscletone
  • General weakness
  • Renal disorders.

Question 28.
Differentiate Glycogenolysis from gluconeogenesis.
Answer:

  • Glycogenolysis is breakdown of glycogen to glucose
  • This process is carried out in the liver by the Glucagon hormone.
  • Glucagon thus releases glucose from the liver cells increasing Gluconeogenesis.
  • it is the synthesis of glucose from lactic acid and from non-carbohvdrate molecules is called Gluconeogenesis. this increases the blood glucose levels.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 29.
Mention the symptoms of diabetes mellitus.
Answer:

  • Poly urea – Excessive urination
  • Polyphagia – Excessive intake of food
  • Polydipsia – Excessive consumption of liquids due to thirst.
  • Ketosis – Breakdown of fat into glucose results in accumulation of ketone bodies.

Question 30.
Give a short account on hypothalamus.
Answer:

  • Hypothalamus is a small cone shaped structure that projects downward from the brain ending into the pituitary stalk.
  • It interlinks both the nervous system and endocrine system.
  • Pituitary gland is controlled by the hypothalamus.
  • It produces neuro transmitters which act either as a releasing hormone or as an inhibitory hormone.
  • Hypothalamus contains groups of neuro secretory cells which produces neuro transmitters which regulate the secretions of the pituitary gland.

Question 31.
Comment on pineal gland.
Answer:

  • It is located behind the third ventricle of brain.
  • In human it is called epiphysis cerebri conarium.
  • It is formed of parenchymal cells and interstitial cells.
  • It secretes the hormone melatonin.
  • It plays a central role in the regulation of circadian rhythm of our body and maintains the normal sleep wake cycle.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 32.
Write down the functions of thyrocalcitonin.
Answer:

  1. It is a polypeptide hormone.
  2. It regulates the blood calcium and phosphate levels.
  3. It reduces the blood calcium level and oppose the effects of parathyroid hormone.

Question 33.
Give a brief account on parathyroid gland.
Answer:

  • In man, four tiny parathyroid glands are found in the posterior wall of the thyroid glands.
  • It composed of two types of cells. The chief cells and oxyphil cells.
  • The chief cells secrete parathyroid hormone.
  • The functions of oxyphil cells are not known.

Question 34.
Write short notes on thymus gland.
Answer:

  • Thymus gland is partially an endocrine and partially a lymphoid gland.
  • It is a bi-lobed structure located just above the heart and aorta behind the sternum.
  • It is covered by a fibrous capsule.
  • Anatomically it is divisible into an outer cortex and an inner medulla.
  • It secretes four hormones such as thymulin, thymosin, thymopoietin and thymic humoral factor (THF).
  • The primary function is the production of immuno competent T lymphocytes which provides cell mediated immunity.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 7

Question 35.
Write about Acromegaly.
Answer:
Acromegaly is due to excessive secretion of growth hormone in adults.
Symptoms:-

  • Over growth of hand bones, feet bones, jaw bones
  • Malfunctioning of gonads
  • Enlargement of viscera, tongue, lungs, heart, liver, spleen and endocrine gland like thyroid adrenal.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 36.
What is hyperparathyroidism? Write down its symptoms.
Answer:
1. Hyperparathyroidism is caused due to excess parathyroid hormone in blood.
Symptoms:-

  • Demineralisation of bones
  • Cyst formation, softening of bone.
  • Loss of muscle tone
  • General weakness
  • Renal disorders.

Question 37.
Comment on Addison’s disease.
Answer:
Addison’s disease is caused due to hyposecretion of glucocorticoids and mineralocorticoids from the adrenal cortex.
Symptoms:-

  • Muscular weakness, Low BP
  • Loss of appetite, vomiting
  • Hyper pigmentation of the skin
  • Low metabolic rate, subnormal temperature.
  • Weight loss reduced blood volume.
  • Low aldosterone level increases urinary excretion of NaCl and water and decreases potassium excretion leading to dehydration.

Question 38.
Give reasons for Diabetes insipidus and point out its symptoms.
Answer:
Diabetes insipidus is caused due to hypo secretion of vasopressin.
Symptoms:-

  • Polyurea-frequent urination
  • Polydipsia – excessive consumption of liquids due to thirst.

Question 39.
Define BMR.
Answer:
The amount of energy needed to keep the body at rest.

Question 40.
Write down the general function of adrenalin hormone and its nature of secretion?
Answer:
Function:- The general function of nor adrenalin is to mobilize the brain and body for action. Nature of secretion: Its secretion is less during sleep, more during wakefulness and reaches much higher levels during stress situations. This response is known as ‘fight or flight’ response.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 41.
Old age people are sick often why?
Answer:
Due to degeneration of thymus gland, thymosin level decreases as a result the immunity of old age people becomes weak and causes sickness.

Question 42.
What is the role of pass intermedia in mammals and in other vertebrates?
Answer:

  • In mammals the role of pass intermedia is insignificant.
  • In other vertebrates it secretes melanocyte stimulating hormone (MSH)
  • It induces pigmentation in skin.

(5 Marks)

IV. Brief Answers

Question 1.
Describe the mechanism of peptide hormone action with a diagram.
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 8

  • Peptide hormones cannot cross the phospholipid cell membrane and bind to the receptors on the exterior cell surface.
  • They are transported to the golgi which is the site of modification.
  • It acts as a first messenger in the cell.
  • Hormones generate a second messenger like cyclic AMP (cAMP) that regulates cellular metabolism. This cAMP is catalyzed by the adenylate cyclase ezyme.
  • The interaction between the hormone surface and the effect of cAMP within the cell is known as a signaling cascade. There may be amplication at each step.
  • One hormone molecule may bind to multiple receptor molecules before it is degraded.
  • Each receptor activates to form more cAMP and produces more signals.

Question 2.
Describe the mechanism of action of steroid hormone.
Answer:

  • Steroid hormones can easily cross the cell membrane and bind their receptors which may be intracellular or intercellular.
  • Then they pair up with another receptor and form a receptor-hormone complex. This can bind to DNA and alter its transcription.
  • As it changes the mRNA and protein the effect will be with stand for a long time. Eg. Estrogen

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 9

Question 3.
What is typical about Addison’s disease.
Answer:

  • There is a hyper pigmentation of the skin. It is caused due to hypo secretion of glucocorticoids from the adrenal cortex.
  • Muscular weakness low BP, loss of appetite vomiting, low metabolic rate subnormal temperature reduced blood volume and weight are the other symptoms of Addison’s disease.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 4.
What is the cause of cretinism? What are the symptoms?
Answer:

  • Hypothyroidism is the cause of cretinism in infants. There is a retarded skeletal growth absence of sexual maturity, retarded mental ability, thick wrinkled skin protruded enlarged tongue bloated face thick and short limbs.
  • There is low BMR, slow pulse rate subnormal body temperature and elevated blood cholesterol levels.

Question 5.
What are the hormones responsible for maintaining blood glucose levels?
Answer:
Insulin and glucagon are the hormones secreted by Islets of Langerhans of the pancreas:-
Insulin:
Insulin is a peptide hormone and plays an important role in glucose homeostasis. Its main effect is to lower blood glucose levels by increasing the uptake of glucose into the body cells, especially muscle and fat cells. Insulin also inhibits the breakdown of glycogen to glucose, the conversion of amino acids or fats to glucose, so insulin is rightly called a hypoglycemic hormone.

Glucagon:
Glucagon is a polypeptide hormone. It is a potent hyperglycaemic hormone that acts on the liver and promotes the breakdown of glycogen to glucose (Glycogenolysis), synthesis of glucose from lactic acid and from non-carbohydrate molecules (gluconeogenesis).

Releases glucose from the liver cells, increasing the blood glucose levels. Since glucagon reduces the cellular uptake and utilisation of glucose it is called a hyperglycemic hormone. Prolonged hyperglycemia leads to the disorder called diabetes mellitus.

Question 6.
What is an exophthalmic goiter? What are its symptoms?
Answer:
This disease is caused due to hyper secretion of the thyroid.
Symptoms:

  • Enlargement of the thyroid gland
  • Increased BMR.
  • Elevated respiratory and excretory rates
  • Increased heart beat
  • High blood pressure
  • Increased body temperature
  • Protection of eye ball (Exophthalmic)
  • The weakness of eye muscles
  • Weight loss.

Question 7.
What is meant by negative feedback mechanism? Explain with an example.
Answer:
When the thyroxine level in the blood decreases it is sensed by the hypothalamus to release the thyroid releasing factor that induces the pituitary to secrete thyroid stimulating hormone that stimulates the thyroid to release thyroxine – when the thyroxine level in the blood increases TTH acts on both the pituitary and hypothalamus to inhibit TSH secretion. This is meant by negative feedback mechanism.
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 10

Question 8.
Why parathormone is considered as a hypercalcemic hormone.
Answer:

  • It increases the blood calcium level by stimulating osteo clasts to dissolve the bone matrix.
  • It enhances the reabsorption of calcium and also increases calcium adsorption by intestinal mucosal cells.
  • By all these action it increases the blood calcium level. Hence it is known as hypercalcemic hormone.

Question 9.
Write on Hyperthyroidism and Hypothyroidism?
Answer:
In infants, hypothyroidism causes cretinism. A cretin shows retarded skeletal growth, absence of sexual maturity, retarded mental ability, thick wrinkled skin, protruded enlarged tongue, bloated face, thick and short limbs occurs. The other symptoms are low BMR, slow pulse rate, subnormal body temperature and elevated blood cholesterol level.

Hyposecretion of the thyroid in adults causes myxoedema. It is otherwise called Gull’s disease. This disease is characterised by decreased mental activity, memory loss, slowness of movement, speech, and general weakness of body, dry coarse skin, scarce hair, puffy appearance, disturbed sexual function, low BMR, poor appetite, and subnormal body temperature.

Grave’s disease also called thyrotoxicosis or exophthalmic goiter. This disease is caused due to hypersecretion of the thyroid. It is characterised by enlargement of the thyroid gland, increases BMR (50% -100%), elevated respiratory and excretory rates, increased heartbeat, high BP, increases body temperature, protrusion of eyeball, and weakness of eye muscles and weight loss.

Simple goitre is also known as Endemic goitre. It is caused due to hyposecretion of thyroxine. The symptoms include enlargement of thyroid gland, fall in serum thyroxine level, increases TSH secretion.

Question 10.
Give an account of the actions of insulin.
Answer:

  • Insulin lowers the blood glucose level by increasing the uptake of glucose into the body cells.
  • It inhibits the conversion of amino acids or fat to glucose.
  • Insulin is called a hypoglycemic hormone.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 11.
Write on the disorders associated with parathryroid gland?
Answer:
Tetany is caused due to the hyposecretion of parathyroid hormone (PTH). Due to hyposecretion of PTH serum calcium level decreases (Hypocalcemia), as a result serum phosphate level increases. Calcium and phosphate excretion level decreses. Generalized convulsion, locking of jaws increased heart beat rate, increases body temperature, muscular spasm are the major symptoms of tetany. Hyperparathyroidism is caused due to excess PTH in blood. Demineralisation of bone, loss of muscle tone, general weakness, renal disorders are the symptoms of hyperparathyroidism.

Question 12.
a) What are the systems that regulate and co-ordinate the physiological functions of our body?
b) Give the meaning of the word “Hormone”.
c) What are the general characters of hormone?
Answer:
a) The systems that regulate and co-ordinate the physiological functions of our body are

  • Nervous or neural system
  • Endocrine system

b) The meaning of the word “Hormone”is “to excite”
c) General characters of hormones:

  • The endocrine system influences the metabolic activities through the hormones
  • These are chemical messengers released in to the blood and acts specifically on certain target organs or target tissues.
  • Hormones may speed up or slow down or alter the activity of the target organs.
  • Hormones secreted do not remain permanently in the blood.
  • After their function they are converted by the liver into inactive compounds and excreted by the kidneys.

Question 13.
Write a paragraph on different types of diabetes mellitus?
Answer:
Hyperglycaemia is otherwise known as Diabetes mellitus. Is caused due to reduced secretion of insulin. As the result, the blood glucose level is elevated. Diabetes mellitus is of two types, Type! Diabetes and Type II Diabetes. Type I diabetes is also known as Insulin-dependent diabetes, caused by the lack of insulin secretion due to illness or viral infections. Type II diabetes is also known as Non-Insulin dependent diabetes, caused due to reduced sensitivity to insulin, often called insulin resistance.

Symptoms of diabetes include polyuria (excessive urination), polyphagia (excessive intake of food), polydipsia (excessive consumption of liquids due to thirst), ketosis (the breakdown of fat into glucose results in accumulation of ketone bodies) in blood. Gluconeogenesis (Conversion of non-carbohydrate) also occurs in diabetes.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 14.
Give a diagrammatic sketch of the glandular system.
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 11

Question 15.
Tabulate the major hypothalamic hormones and their functions.
Answer:

Hormones Functions
1. Thyrotropin-releasing hormone (TRH) Stimulates the secretion of TSH
2. Gonadotropin-releasing hormone(GnJRH) Stimulates the secretion of FSH
3. Corticotropin-releasing hormone (CRH) Stimulates the secretion of ACTH
4. Growth hormone-releasing hormone (GHRH) Stimulates the secretion of GH
5. Prolactin releasing hormone (PRH) Stimulates the secretion of Prolactin
6. Luteinizing hormone-releasing hormone (LHRH) Stimulates the secretion of LH
7. MSH releasing hormone Stimulates the secretion of MSH
8.Growth hormone-inhibiting hormone(GHIH) Inhibits the secretion of GH
9. Prolactin inhibiting hormone (PIEI) Inhibits the secretion of Prolactin
10. MSH inhibiting hormone Inhibits the secretion of MSH

Question 16.
Discuss the role of the hypothalamus and pituitary as a coordinated unit in maintaining the physiological process.
Answer:

  • Hypothalamus is a small cone-shaped structure that projects downward from the brain ending into the pituitary stalk.
  • It interlinks both the nervous system and endocrine system.
  • Hypothalamus contains a group of neuro secretary cells and it produces neuro transmitters which regulate the secretions of the pituitary.
  • The hormones produced by the hypothalamus act either as a releasing hormone or as an inhibitory hormone.
  • Though the pituitary gland is known as the master endocrine glands really it is in turn controlled by the hypothalamus.
  • The hypothalamus and pituitary gland are anatomically different they are interlinked and functioning as a co-ordinated unit in maintaining the physiological process. They can not functions as a separated unit.
  • The hypothalamic hypophyseal portal blood vessel allows hypothalamic hormones to control the anterior pituitary.
  • The nerve signal produced by the hypothalamic hypophyseal axis (nerve bundle) controls the posterior pituitary secretion.
  • Hypothalamus maintains homeostasis.
  • Maintains blood pressure, body temperature cardio, and fluid-electrolyte balance of the body it influences emotional responses.
  • The pituitary gland through its hormones performs various functions.

Question 17.
Give the classification of hormones based on their chemical nature?
Answer:

Class Chemical properties Example
Amines Small, water-soluble derived from tyrosine or tryptophan Adrenalin, nor adrenalin, melatonin, and thyroid hormone
Protein/ Peptides Water-soluble Insulin, glucagon, and pituitary hormones
Steroids Derived from cholesterol mostly lipid-soluble Cortisol, aldosterone, testosterone, oestrogen, progesterone.

Question 18.
Explain the structure of Testis?
Answer:

  • A pair of the testis is present in the scrotal sac of males.
  • The testis functions as a sex organ and also as an endocrine gland.
  • Testis composed of seminiferous tubules and Ley dig cells.
  • Lay dig cells secrete several male sex hormones collectively called Androgens.
  • The main male sex hormone is Testosterone.

Functions of Testosterone:

  1. Under the influence of FSH and LH, testosterone initiates the maturation of the male reproductive organ.
  2. The appearance of secondary sexual characters. Eg. Muscular growth, growth of facial and axillary hair, masculine voice, and male sexual behaviour.
  3. It enhances the total bone matrix and stimulating the process of spermatogenesis.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 19.
Give a brief account of the ovary.
Answer:

  • Females have a pair of ovaries located in the pelvic region of the abdomen.
  • It is composed of ovarian follicles and stromal tissue.
  • It produces the egg or ova.
  • It secretes the steroid hormones oestrogen and progesterone.

Functions:

  1. Oestrogen is responsible for the maturation of reproductive organs and the development of secondary sexual characters at puberty.
  2. Along with progesterone, oestrogen promotes breast development and initiates the menstrual cycle.
  3. Progesterone prepares the uterus for implantation of the fertilized ovum.
  4. It decreases the uterine contraction during pregnancy and stimulates the development of mammary glands and milk secretion.
  5. It is responsible for premenstrual changes in the uterus and for the formation of the placenta.

Question 20.
Explain the functions of hormones of the heart and kidney.
Answer:
Heart: The cardiocytes on the atrial walls secrete an important peptide hormone called atrial natriuretic factor (ANF)

Function: When blood pressure is increased ANF is secreted and causes dilation of the blood vessels to reduce the blood pressure.

Kidney: Three hormones are secreted by the kidneys. They are Renin, erythropoietin, and calcitriol.

Renin:

  • It is secreted by Juxta glomerular Cells (JGA).
  • It increases blood pressure when angiotensin is formed in the blood.

Erythropoietin:

  • It is also secreted by JGA.
  • Stimulates erythropoiesis ie formation of RBC in bone mawow.

Calcitriol:

  • It is secreted by proximal tubules of the nephron.
  • It is an active form of vitamin D3.
  • It promotes calcium and phosphorus absorption from the intestine and accelerates bone formation.

Question 21.
If you happen to see a man/lady with short stature how will you identify him?
Differentiate and give a reason for that disorder.
Answer:
The person may be suffering from either cretinism or Dwarfism.
The following symptoms may be observed in cretinism. It is due to the hypo-secretion of Thyroxine.

  • A cretin shows retarded skeletal growth.
  • Absence of sexual maturity.
  • Retarded mental ability.
  • Thick wrinkled skin.
  • Protruded enlarged tongue.
  • Bloated face.
  • Thick and short limb occur
  • Low BMR
  • Slow pulse rate.
  • Subnormal body temperature
  • Elevated blood cholesterol levels.

If the person shows the following symptom, he may have Dwarfism, it is due to hyposecretion of growth hormone.

  1. Skeletal growth and sexual maturity is arrested.
  2. They attain a maximum height of 4 feet only.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 22.
(i) Describe the structure of the pancreas.
(ii) Draw the diagram and marced it parts
(iii) How insulin controls blood sugar?
(iv) What is the role of glucagon in our body?
Answer:
i) Structure of pancreas:

  • Pancreas is a composite gland which performs both endocrine and exocrine functions.
  • It is located just below the stomach as a leaf-like structure.
  • It is composed of two major tissues such as acme and islets of Langerhans
  • Acme secretes digestive enzymes and the islets of Langerhans secretes hormones like insulin and glucagon.
  • Human pancreas has 1 -2 million islets of Langerhans.
  • In each islet about 60% cells are beta cells 25% cells are alpha cells and 10% are delta cells.
  • The alpha cells secrete glucagon the beta cells secrete insulin and delta cells secrete somatostatin.

ii) Structure of Islets of Langerhans (pancreas)
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 12

iii) Insulin control-blood sugar:-

  • Insulin is a peptide hormone and plays an important role in glucose homeostasis.
  • Its main effect is to lower blood glucose levels by increasing the uptake of glucose into the body cells
  • especially muscle and fat cells.
  • Insulin also inhibits the breakdown of glycogen to glucose, the conversion of amino acids or fats to glucose.
  • So insulin is rightly called a hypoglycemic hormone.
  • Reduced secretion of insulin leads to diabetes mellitus. As a result glucose level is elevated.
  • It is of two types. Type I. Diabetes and Type II Diabetes. Type I Diabetes is caused by lack of secretion of insulin due to illness or viral infection. Type II or Non-insulin-dependent diabetes caused due to reduced sensitivity to insulin.

iv) Role of Glucagon:

  • Glucagon is a polypeptide hormone.
  • It is a potent hyper glycemic hormone.
  • It acts on the liver and promotes the break down of glycogen to glucose (glycogenolysis)
  • It also promotes synthesis of glucose from lactic acid and from non-carbohydrate molecules is called Gluconeogenesis.
  • Glucogon releases glucose from the liver cell increasing the blood glucose levels.
  • Since glucagon reduces the cellular uptake and utilisation of glucose it is called a hyperglycemic hormone. Prolonged hyperglycemia leads to the disorder called diabetes mellitus.

Question 23.
Symptoms of diabetes
Answer:

  • Polyurea – excessive urination
  • Polyphagia – excessive intake of food
  • Poly dispsia – excessive consumption of liquids due to thirst.
  • Ketosis – breakdown of fat into glucose results in accumulation of ketone bodies in blood.
  • Gluconeogenesis also occur ie conversion of the non-carbohydrate form like amino acids and fat into glucose.

Question 24.
a) Write down the location and dimension of the pituitary gland?
b) Explain the internal structure of the pituitary gland?
c) Draw the diagram of the pituitary gland and label the parts.
Answer:
a. Location of pituitary gland:-

  • It is located in a depression called sella tursica a bony cavity of the sphenoid bone below the brain.
  • The pituitary gland means “to grow under”.
  • It is connected to the brain by a stalk called the infundibulum
  • Dimension:- It is about 1cm in diameter and 0. 5gm in weight.

b. Internal structure:-

  • The pituitary consists of two lobes, anterior glandular adenohypophysis and posterior neural neuro hypophysis.
  • Anatomically the anterior lobe or adenohypophysis has three lebesor zones namely pass intermedia, pass distalis and pass tuberalis.
  • The neurohypophysis is otherwise known as pars nervosa.
  • Embryonic origin:- The anterior lobe originates from the Embryonic invagination of pharyngeal epithelia called Rathke’s pouch.
  • The posterior lobe originates from the base of the brain as an outgrowth of the hypothalamus.

c. Hypothalamus and pituitary gland
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 13

Question 25.
Give a brief account of the hormones of the adenohypophysis.
Answer:
It secretes six hormones.
1. Growth Hormone:-

  • It is also known as somatotropic hormone (STH) or somatotropin
  • It is a peptide hormone.
  • It promotes the growth of all the tissues and metabolic processes of the body.
  • It influences the metabolism of carbohydrates, proteins, and lipids and increases the rate of biosynthesis in the cells.
  • It stimulates chondrogenesis (cartilage formation), osteogenesis (bone formation).
  • It helps in the retention of minerals like nitrogen and potassium, phosphorous, sodium, etc. in the body.

2. Thyroid Stimulating Hormone TSH or Thyrotropin:-

  • It is a glycoprotein.
  • It stimulates the thyroid gland to secrete Tri-iodothyronine (T3) and Thyroxine (T4).
  • TSH secretion is regulated by a negative feedback mechanism.
  • Its release from the anterior pituitary is induced by the thyrotropin-releasing hormone (TRH).
  • When thyroxine level in the blood increases TRH acts on both the pituitary and hypothalamus to inhibit TSH secretion.

3. Adreno Corticotropic Hormone (ACTH):-

  • It is a peptide hormone.
  • It stimulates the adrenal cortex to secrete glucocorticoids and mineral corticoids.
  • It stimulates melanin synthesis in melanocytes induces the release of fatty acids from adipose tissues and stimulates insulin secretion.
  • its secretion is regulated by a negative feedback mechanism.

4. Follicle Stimulating Hormone (FSH):-

  • It is a glycoprotein hormone.
  • It regulates the functions of the gonads.
  • In males, FSH along with androgens act on the germinal epithelium of seminiferous tubules and stimulates the production and release of sperms (Spermatogenesis).
  • In females, it acts on the ovaries and brings about the development and maturation of graffian follicles.

5. Luteinizing hormone (LH):-

  • It is a glycoprotein hormone.
  • It is also known as interstitial cell-stimulating hormone.
  • In females LH, along with FSH matures the ovarian follicles.
  • LH independently induces ovulation, maintains the corpus luteum and promotes synthesis and release of ovarian hormones.
  • In males, ICSH acts on interstitial cells of testes to produce the male sex hormone testosterone.

6. Luteo Tropic Hormone (LTH):-

  • It is a protein hormone.
  • It is also called luteotropin or lactogenic hormone or prolactin or mammotropin.
  • It stimulates milk secretion after childbirth.
  • Since it induces the corpus luteum hence named as a luteotropic hormone.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 26.
a) Name the hormones secreted by the neuro hypophysis?
b) Give a brief account of its functions?
Answer:
a. Neuro hypophysis secretes two hormones.

  1. Vasopressin or anti-diuretic hormone
  2. Oxytocin.

Vasopressin or Anti diuretic Hormone (ADH):-

  • It is a peptide hormone.
  • it promotes reabsorption of water and electrolytes by distal tubules of the nephron and thereby reduces the loss of water through urine.
  • Hence it is called an anti-diuretic hormone.
  • When released in large amounts it causes constriction of blood vessels and increases blood pressure.
  • ADH deficiency causes Diabetes insipidus which induces the production of a large amount of urine.

Oxytocin:-

  • It means quick birth.
  • It is a peptide hormone.

3. It stimulates vigorous contraction of the smooth muscles of the uterus during childbirth.
4. And it also stimulates the ejection of milk from the mammary glands.

b. Chemical nature:

  • The insulin hormone is a peptide hormone with 51 amino acids.
  • The molecular weight of insulin hormone is 5734 Dalton.
  • It consists of two chains A and B which are linked together by disulphide bridges formed between cystine residues.

Role of Insulin:

  • It increases uptake of glucose into body cells especially muscle and fat cells.
  • It inhibits the breakdown of glycogen to glucose, the conversion of amino acids or fats to glucose.
    Thus it decreases the blood glucose level and so insulin is rightly called as a hypoglycemic hormone.

c. How can this condition be reversed?

  • maintenance of normal body weight through adoption of nutritional habits ie. balanced diet and physical exercise.
  • Correction of over nutrition and obesity may reduce the risk of diabetes and its complications.
  • Alcohol and smoking should be avoided.
  • Control of high blood pressure elevated cholesterol and high triglyceride levels.

Question 27.
a) Why hormones are called chemical messengers?
b) Explain how the target organs are specifically fit for the action of hormones?
Answer:
a) Hormones are chemical messengers because they act as organic catalysts and co-enzymes to perform specific functions in the target organs.

b) Special features of target organs:

  • The target organs contain receptor molecules either on the surface or within the cell.
  • Although different hormones come in contact, only the cells that contain receptor molecules specific to the hormone are physiologically activated.
  • A single hormone may have multiple effects on a single target tissue or on different target tissues.
  • Many hormones exhibit long-term changes like growth, puberty, and pregnancy.
  • Serious deficiency or excess secretion of hormones leads to disorders.
  • Hormones coordinate different physiological mental activities and maintain homeostasis.

Question 28.
Draw the Endocrine gland is our body.
Answer:
Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration 14

Question 29.
Give an account on parathyroid hormones its hypo and hyper secretion deficiencies.
Answer:

  • Four tiny parathyroid glands are found in the posterior wall of the thyroid gland.
  • It is composed of Chief cells and oxyphil cell.
  • The chief cells secrete parathyroid hormone and the function of oxyphill cell are not known

Functions

  • It involves in calcium and phosphate.
  • It promotes the activation of vitamin D to increase calcium absorption by intestine.

Hyper secretion

  • Hyper parathyroidism causes demineral isation of calcium in bones.
  • Thus increasing the calcium and phosphate level in the blood.
  • PTH enhances the reabsorption of calcium and excretion of phosphate by the renal tubules.

Hypo secretion

  • Due to the hyposecretion of PTH serum calcium level decreases and the serum phosphate level increases.
  • Generalised convulsion occurs.

Samacheer Kalvi 11th Bio Zoology Guide Chapter 11 Chemical Coordination and Integration

Question 30.
a. Give an account of position of adrenal gland and it’s internal structure, b. List out the function of adrenal hormone.
Answer:
a) Position
A pair of adrenal glands are located at the anterior end of the kidney. Hence called supra renal glands.
b) Structure
The adrenal gland is composed of the outer cortex and an inner medulla.
The cortex consists of

  1. zona glomerulosa
  2. zona fasciculata
  3. zona reticularis.

1. zona glomerulosa
– secretes minerals corticoids

2. zona fasciculata
– secretes gluco corticoids

3. zona reticularis.
– secretes androgen and oestrogen.

b) Functions

  • Gluco corticoids stimulate gluco neogenesis.
  • Cortisolies involved in maintaining cardio vascular and kidney functions.
  • Cortisol stimulates RBC production.
  • Mineralocorticoids regulated the water and electrolyte balance of our body.
  • Androgen plays a role in hair growth in the axial region pubis and face during Puberty.