Students get through the TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration which is useful for their exam preparation.

TN State Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Answer the following.

Question 1.
In what way the process of respiration is related with the process of release of energy from food?
The process of breathing is connected to the process of release of energy from food. Oxygen is utilized by the organisms to breakdown the biomolecules like glucose and to derive energy. During this breakdown carbondioxide, which is a harmful gas is also released. It is very obvious that oxygen has to be provided to cells continuously and the CO2 to be released immediately by the cells. So the need of a respiratory system is essential for life.

Question 2.
Define respiration.
The term respiration refers to the exchange of oxygen and carbondioxide between environment and cells of our body where organic nutrients are broken down enzymatically to release energy.

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 3.
Discuss the five primary functions of the respiratory system.
The five primary functions of the respiratory system are:

  1. To exchange O2 and CO2 between the atmosphere and the blood.
  2. To maintain homeostatic regulation of body pH.
  3. To protect us from inhaled pathogens and pollutants.
  4. To maintain the vocal cords for normal communication (vocalization).
  5. To remove the heat produced during cellular respiration through breathing.

Question 4.
The rate of breathing in aquatic organisms is much faster than land animals. Why?
Different animals have different organs for exchange of gases, depending upon their habitats and levels of organization. The amount of dissolved oxygen is very low in water compared to the amount of oxygen in the air. So the rate of breathing in aquatic organisms is much faster than land animals.

Question 5.
Write the respiratory organs of the following.
Coelenterates, earthworm, insects, molluscs, fishes, reptiles, frog.

  1. Coelenterates the body surface by simple diffusion.
  2. Earthworms use their moist skin.
  3. Insects have tracheal tubes.
  4. Gills are used as respiratory organs in most of the aquatic Arthropods and Molluscs.
  5. Fishes use gills.
  6. Reptiles and mammals have well vascularised lungs.
  7. Frogs use their moist skin for respiration along with the lungs.

Question 6.
Write the respiratory passage of human.
The respiratory system includes the external nostrils, nasal cavity, the pharynx, the larynx, the trachea, the bronchi and bronchioles and the lungs which contain the alveoli.

Question 7.
What is the use of epithelial cells lining the trachea.

  1. The ciliated epithelial cells lining the trachea, bronchi and bronchioles secrete mucus.
  2. The mucus membrane lining the airway contains goblet cells which secrete mucus, a slimy material rich in glycoprotein.
  3. Microorganisms and dust particles attach in the mucus films and are carried upwards to pass down the gullet during normal swallowing

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 8.
Name the three layers of alveoli.
The diffusion membrane of the alveolus is made up of three layers – the thin squamous epithelial cells of the. alveoli, the endothelium of the alveolar capillaries and the basement substance found in between them.

Question 9.
Name the cells and their nature that are present in the alveoli.
The thin squamous epithelial cells of the alveoli are composed of Type I and Type II cells. Type I cells are very thin so that gases can diffuse rapidly through them. Type II cells are thicker, synthesize and secrete a substance called Surfactant.

Question 10.
Write about the location of the lungs and its structure briefly.

  1. The lungs are light spongy tissues enclosed in the thoracic cavity surrounded by an airtight space.
  2. The thoracic cavity is bound dorsally by the vertebral column and ventrally by the sternum, laterally by the ribs and on the lower side by the dome-shaped diaphragm.
  3. The lungs are covered by double-walled pleural membrane containing several layers of elastic connective tissues and capillaries, which encloses the pleural fluid. Pleural fluid reduces friction when the lungs expand and contract.

Question 11.
What are the characteristic features of the respiratory surface?
Characteristic features of respiratory surface:

  1. The surface area must be very large and richly supplied with blood vessels.
  2. Should be extremely thin and kept moist.
  3. Should be in direct contact with the environment.
  4. Should be permeable to respiratory gases.

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 12.
Write the steps involved in respiration.
The steps involved in respiration are

  1. The exchange of air between the atmosphere and the lungs.
  2. The exchange of O2 and CO2 between the lungs and the blood.
  3. Transport of O2 and CO2 by the blood.
  4. Exchange of gases between the blood and the cells.
  5. Uptake of O2 by the cells for various activities and the release of CO2.

Question 13.
What is meant by ‘SURFACTANT’?
Surfactants are thin non-cellular films made of protein and phospholipids covering the alveolar membrane. The surfactant lowers the surface tension in the alveoli and prevents the lungs from collapsing. It also prevents pulmonary oedema.

Question 14.
What is ‘NRDS’?
Premature Babies have low levels of surfactant in the alveoli may develop the new bom respiratory distress syndrome (NRDS) because the synthesis of surfactants begins only after the 25th week of gestation.

Question 15.
What is breathing? What are the steps involved?
The movement of air between the atmosphere and the lungs is known as ventilation or breathing. Inspiration and expiration, are the two phases of breathing. Inspiration is the movement of atmospheric air into the lungs and expiration is the movement of alveolar air that diffuse out of the lungs.

Question 16.
What are the muscles involved in the action of the lungs?
Lungs do not contain muscle fibres but expands and contracts by the movement of the ribs and diaphragm. The diaphragm is a sheet of tissue that separates the thorax from the abdomen.
In a relaxed state, the diaphragm is dome-shaped. Ribs are moved by the intercostal muscles. External and internal intercostal muscles found between the ribs and the diaphragm helps in creating pressure gradients.

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 17.
How the difference of pressure gradient helps in inspiration?
Inspiration occurs if the pressure inside the lungs (intrapulmonary pressure) is less than the atmospheric pressure likewise expiration takes place when the pressure within the lungs is higher than the atmospheric pressure.

Question 18.
What is inspiration?
The increase in pulmonary volume and decrease in the intrapulmonary pressure forces the fresh air from outside to enter the air passages into the lungs to equalize the pressure. This process is called inspiration.

Question 19.
What is expiration?
Relaxation of the diaphragm allows the diaphragm and sternum to return to its dome shape and the internal intercostal muscles contract, pulling the ribs downward reducing the thoracic volume and pulmonary volume. This results in an increase in the intrapulmonary pressure slightly above the atmospheric pressure causing the expulsion of air from the lungs. This process is called expiration.

Question 20.
Explain about the different respiratory volumes and capacities of lungs.
Respiratory Volumes – Tidal Volume (TV): Tidal volume is the amount of air inspired or expired with each normal breath. It is approximately 500 mL., i.e. a normal human adult can inspire or expire approximately 6000 to 8000mL of air per minute. During vigorous exercise, the tidal volume is about 4-10 times higher.
Inspiratory Reserve volume (IRV): Additional volume of air a person can inspire by forceful inspiration is called Inspiratory Reserve Volume. The normal value is 2500 to 3000 mL.
Expiratory Reserve volume (ERV): Additional volume of air a person can forcefully exhale by forceful expiration is called Expiratory Reserve Volume. The normal value is 1000 -1100 mL.
Residual Volume (RV): The volume of air remaining in the lungs after a forceful expiration. It . is approximately 1100 – 1200 mL.
Respiratory capacities – Vital capacity (VC): The maximum volume of air that can be moved out during a single breath following a maximal inspiration. A person first inspires maximally then expires maximally.
Inspiratory capacity (IC): The total volume of air a person can inhale after normal expiration.
It includes tidal volume and inspiratory reserve volume. IC = TV + IRV.
Expiratory capacity (EC): The total volume of air a person can exhale after normal inspiration.
It includes tidal volume and expiratory reserve volume. EC = TV + ERV.
Total Lung Capacity (TLC): The total volume of air which the lungs can accommodate after forced inspiration is called Total Lung Capacity. This includes the vital capacity and the esidual volume. It is approximately 6000mL. TLC = VC + RV.
Minute Respiratory Volume: The amount of air that moves into the respiratory passage per minute is called minute respiratory volume.
Normal TV = 500mL; Normal respiratory rate = 12 times/minute. Therefore, minute respiratory volume = 6 Litres/minute (for a normal healthy man).

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 21.
Define ‘Dead Space’.
The inspired air never reaches the gas exchange areas but fills the respiratory passages where the exchange of gases does not occur. This air is called dead space. Dead space is not involved in gaseous exchange. It amounts to approximately 150mL.

Question 22.
Write in a tabular form giving information about the partial pressure of respiratory gases in different regions of the respiratory system and in tissues.
Partial pressure of oxygen and carbon di oxide (in mmHg) in comparison to those gases in the atmosphere.
TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration 1

Question 23.
How the blood transports the oxygen to the tissues.
Molecular oxygen is carried in blood in two ways: bound to haemoglobin within the red blood cells and dissolved in plasma. Oxygen is poorly soluble in water, so only 3% of the oxygen is transported in the dissolved form. 97% of oxygen binds with haemoglobin in a reversible manner to form oxyhaemoglobin (HbO2). The rate at which haemoglobin binds with O2 is regulated by the partial pressure of O2. Each haemoglobin carries a maximum of four molecules of oxygen. In the alveoli high pO2, low pCO2, low temperature and less H+ concentration, favours the formation of oxyhaemoglobin, whereas in the tissues low pO2, high pCO2, high H+ and high temperature favours the dissociation of oxygen from oxyhaemoglobin.

Question 24.
What is a sigmoid curve and how is it obtained.
A sigmoid curve (S-shaped) is obtained when the percentage saturation of haemoglobin with oxygen is plotted against pO2. This curve is called the oxygen haemoglobin dissociation curve. This S-shaped curve has a steep slope for pO2 values between 10 and 50mm Hg and then flattens between 70 and 100 mm Hg.
TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration 2

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 25.
How blood transports CO2 from the tissue cells.
Blood transports CO2 from the tissue cells to the lungs in three ways

  1. Dissolved in plasma About 7 -10% of CO2 is transported in a dissolved form in the plasma.
  2. Bound to haemoglobin About 20 – 25% of dissolved CO2 is bound and carried in the RBCs as carbaminohaemoglobin (Hb CO2) CO2 + Hb Hb CO2
  3. As bicarbonate ions in plasma about 70% of CO2 is transported as bicarbonate ions.

Question 26.
Describe the process of transport of CO2 carried out by haemoglobin.

  1. About 20 – 25% of dissolved CO2 is bound — and carried in the RBCs as carbaminohaemoglobin (Hb CO2).
  2. This is influenced by pCO2 and the degree of haemoglobin oxygenation. RBCs contain a high concentration of the enzyme, carbonic anhydrase, whereas small amounts of carbc’ric anhydrase is present in the plasma.
  3. At the tissues, the pCO2 is high due to catabolism and diffuses into the blood to form HCO3 and H+ ions.
  4. When CO2 diffuses into the RBCs, it combines with water forming carbonic acid (H2CO3) catalyzed by carbonic anhydrase.
  5. Carbonic acid is unstable and dissociates into hydrogen and bicarbonate ions.
  6. Carbonic anhydrase facilitates the reaction in both directions.
    TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration 3
  7. The HCO3 moves quickly from the RBCs into the plasma, where it is carried to the lungs. At the alveolar site where pCO2 is low, the reaction is reversed leading to the formation of CO2 and water. Thus CO2 trapped as HCO3 at the tissue level it is transported to the alveoli and released out as CO2.

Question 27.
Write the events that make differences between inspiration and expiration.
TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration 4

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 28.
Write short notes on nitrogen narcosis.
When a person descends deep into the sea, the pressure in the surrounding water increases which causes the lungs to decrease in volume. This decrease in volume increases the partial pressure of the gases within the lungs. This effect can be beneficial, because it tends to drive additional oxygen into the circulation, but this benefit also has a risk, the increased pressure can also drive nitrogen gas into the circulation. This increase in blood nitrogen content can lead to a condition called nitrogen narcosis.

Question 29.
What is ‘bends’ and how it is risky in scuba divers.
When the diver ascends to the surface too quickly a condition called ‘bends’ or decompression sickness occurs and nitrogen comes out of solution while still in the blood-forming bubbles. Small bubbles in the blood are not harmful, but large bubbles can lodge in small capillaries, blocking blood flow or can press on nerve endings. Decompression sickness is associated with pain in joints and muscles and neurological problems including a stroke. The risk of nitrogen narcosis and bends is common in scuba divers.

Question 30.
Define the following terms and write their symptoms also.

  1. Asthma,
  2. emphysema,
  3. bronchitis,
  4. pneumonia,
  5. tuberculosis,
  6. Occupational respiratory disorders.


  1. Asthma: It is characterized by narrowing and inflammation of bronchi and bronchioles and difficulty in breathing. Common allergens for asthma are dust, drugs, pollen grains, certain food items like fish, prawn and certain fruits etc.
  2. Emphysema: Emphysema is chronic breathlessness caused by the gradual breakdown of the thin walls of the alveoli decreasing the total surface area of gaseous exchange, i.e., widening of the alveoli is called emphysema. The major cause of this disease is cigarette smoking, which reduces the respiratory surface of the alveolar walls.
  3. Bronchitis: The bronchi when it gets inflated due to pollution smoke and cigarette smoking, causes bronchitis. The symptoms are cough, shortness of breath and sputum in the lungs.
  4. Pneumonia: Inflammation of the lungs due to infection caused by bacteria or virus is called pneumonia. The common symptoms are sputum production, nasal congestion, shortness of breath, sore throat, etc.
  5. Tuberculosis: Tuberculosis is caused by Mycobacterium tuberculae. This infection mainly occurs in the lungs and bones. The collection of fluid between the lungs and the chest wall is the main complication of this disease.
  6. Occupational respiratory disorders: The disorders due to one’s occupation of working in industries like grinding or stone breaking, construction sites, cotton industries, etc. Dust produced affects the respiratory tracts. Long exposure can give rise to inflammation leading to fibrosis. Silicosis and asbestosis are occupational respiratory diseases resulting from inhalation of a particle of silica from sand grinding and asbestos into the respiratory tract. Workers, working in such industries must wear protective masks.

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

Question 31.
How smoking causes a series of effects in our organ system.

  1. Smoking is inhaling the smoke from burning tobacco.
  2. There are thousands of known chemicals which include nicotine, tar, carbon monoxide, ammonia, sulphur dioxide and even small quantities of arsenic.
  3. Carbon monoxide and nicotine damage the cardiovascular system and tar damages the gaseous exchange system.
  4. Nicotine is the chemical that causes addiction and is a stimulant that makes the heart beat faster and the narrowing of blood vessels results in raised blood pressure and coronary heart diseases.
  5. The presence of carbon monoxide reduces oxygen supply.
  6. Lung cancer, cancer of the mouth and larynx is more common in smokers than non-smokers.
  7. Smoking also causes cancer of the stomach, pancreas and bladder and lowers sperm count in men.
  8. Smoking can cause lung diseases by damaging the airways and alveoli and results in emphysema and chronic bronchitis.
  9. These two diseases along with asthma are often referred as Chronic Obstructive Pulmonary Disease (COPD).

Question 32.
What will happen when a person travels quickly from sea level to an elevation above 8000ft?
When a person travels quickly from sea level to elevations above 8000ft, where the atmospheric pressure and partial pressure of oxygen are lowered, the individual responds with symptoms of acute mountain sickness (AMS) headache, shortness of breath, nausea and dizziness due to poor binding of O2 with haemoglobin.

Answer the following.

1. The tracheal tube of a human is supported by:
(a) Bones
(b) Cartilaginous rings
(c) Tracheal filaments
(d) Epiglottis.
(b) Cartilaginous rings

2 is used to measure the volume of air involved in breathing movement for clinical assessment.
(a) Sphygmomanometer
(b) Clinical thermometer
(c) Spirometer
(d) Haemocytometer.
(c) Spirometer

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

3 . An average, healthy human breathes times/minute.
(a) 12-16
(b) 13-17
(c) 12-18
(d) 10-16
(a) 12-16

4. During vigorous exercise, the tidal volume of each respiration is about this much times higher:
(a) 6 times
(b) 10-12 times
(c) 4-10 times
(d) more than 5 times
(c) 4-10 times

5. Minute respiratory volume for a normal healthy man is:
(a) 12 liters/minute
(b) 150 ml/minute
(c) 5 liters/minute
(d) 6 liters/minute
(d) 6 liters/minute

6. The partial pressure of O2 in the oxygenated blood is:
(a) 104 mmHg
(b) 95 mmHg
(c) 159 mmHg
(d) 45 mmHg
(b) 95 mmHg

7. Breakdown of thin wall of the alveoli will leads to:
(a) Emphysema
(b) Asthma
(c) Pneumonia
(d) Bronchitis
(a) Emphysema

TN Board 11th Bio Zoology Important Questions Chapter 6 Respiration

8. Tuberculosis is caused by:
(a) Vibrio cholerae
(b) Helicobacter pylori
(c) Mycobacterium tuberculae
(d) Mycoplasma
(c) Mycobacterium tuberculae

9. The world TB day is:
(a) March 24th
(b) April 23rd
(c) October 12th
(d) March 12th
(a) March 24th

10. When our brain sense the shortage of O2, it sends a message to CNS to imbalance to 02 demand and trigger us to:
(a) Snore
(b) Hiccups
(c) Sneeze
(d) Yawn
(d) Yawn