Tiêu đề 17 Breathing n exchange of gases - Topic wise complete Q n A.pdf ✅

© www.bankofbiology.com All rights reserved. 90 17. BREATHING AND EXCHANGE OF GASES HUMAN RESPIRATORY SYSTEM 1. In human being, the sound is produced by (Score 1) (a) Pharynx (b) Larynx (c) Trachea (d) Bronchi  Answer: (b) Larynx 2. Each terminal bronchiole gives rise to many very thin and vascularised ................ (Score 1)  Answer: Alveoli 3. Lungs situate in thoracic chamber and rest on ............. (Score 1)  Answer: Diaphragm 4. .......... are the structural and functional units of lungs. (Score 1)  Answer: Alveoli 5. Analyze the concept map given below and if have any mistake, reconstruct it. (Score 2)  Answer 6. Besides transporting of atmospheric air into the alveoli, conducting part of the respiratory system performs other functions. Mention any two of them. (Score 2)  Answer Conducting part clears air from foreign particles, humidifies and brings the air to body temperature. 7. Complete the flowchart showing the steps of respiration. (Score 2)  Answer: A. Diffusion of O2 and CO2 across alveolar membrane. B. Transport of gases by the blood. C. Diffusion of O2 and CO2 between blood and tissues. D. Cellular respiration. 8. Draw a flowchart showing the different parts of the air tract. (Score 3)  Answer External nostrils → nasal passage → nasal chamber → pharynx → glottis → larynx → trachea → primary bronchi → secondary bronchi → tertiary bronchi → bronchioles → terminal bronchioles. 9. Being a vital organ, lungs have a double layered covering for protection. a) Name the protective covering. b) Name its outer and inner layers. c) Mention the name of fluid present between these two layers and its function. (Score 3)  Answer a) Pleura b) Outer Parietal pleura and inner visceral pleura. c) Pleural fluid. It lubricates the surface of the lungs and prevents friction between the membranes. MECHANISM OF BREATHING (INSPIRATION & EXPIRATION) 10. Observe the figure. State the various steps involved during inspiration and expiration. (Score 3) OR Describe the role of diaphragm and other muscles in breathing. (Score 3)  Answer During inspiration: Diaphragm contracts (flattens) causing an increase in vertical thoracic volume. External intercostal muscles contract to lift up ribs and sternum causing an increase in thoracic volume in the dorso-ventral axis. Increase in thoracic volume reduces thoracic pressure. So, lungs expand. Thus, pulmonary volume increases and intra-pulmonary pressure decreases. So, air moves into lungs (inspiration). During expiration: Pulmonary ventilation (breathing) A B C D Larynx Glottis Epiglottis Opening Guarded by Larynx Epiglottis Glottis Opening Guarded by
© www.bankofbiology.com All rights reserved. 91 Diaphragm relaxes to decrease vertical thoracic volume. External intercostal muscles relax to decrease thoracic volume in the dorso-ventral axis. Decrease in thoracic volume increases thoracic pressure. So, lungs shrink. 11. Match the following: (Score 3) A B C IC TV + ERV 3500-4500 ml EC ERV + TV + IRV 2100-2300 ml FRC TV + IRV 3000-3500 ml VC ERV + RV 1500-1600 ml  Answer A B C IC TV + IRV 3000-3500 ml EC TV + ERV 1500-1600 ml FRC ERV + RV 2100-2300 ml VC ERV + TV + IRV 3500-4500 ml 12. ERV + TV + IRV = ................ (Score 1)  Answer: Vital capacity (VC) 13. Note the relationship between first two words and fill up the fourth place. (Score 1) TV: 500 ml IRV: ..................  Answer: 2500-3000 ml 14. Expand and distinguish between the following terms: a) IRV and ERV b) IC and EC (Score 2)  Answer a. Inspiratory Reserve Volume: Additional volume of air a person can inspire by a forcible inspiration. Expiratory Reserve Volume: Additional volume of air a person can expire by a forcible expiration. b. Inspiratory capacity (IC): Total volume of air inspired after a normal expiration. Expiratory capacity (EC): Total volume of air expired after a normal inspiration. 15. Distinguish between: (Score 2) a) Tidal volume (TV) and Residual volume (RV). b) Vital capacity (VC) and Total lung capacity (TLC).  Answer a. Tidal volume: Volume of air inspired or expired during a normal respiration. Residual volume: Volume of air remaining in lungs after a forcible expiration. b. Vital capacity: Volume of air that can breathe in after a forced expiration. Total lung capacity: Total volume of air in the lungs after a maximum inspiration. 16. (a) What is normal respiratory rate? (b) Name an instrument used for measuring volume of air. (c) Mention its clinical significance. (Score 2)  Answer a) 12-16 times/min b) Spirometer (respirometer) c) Used to diagnose respiratory problems. GAS EXCHANGE 17. Note the relationship between first two words and fill up the fourth place. (Score 1) PO2 in atmospheric air: 159 mm Hg PO2 in alveoli: ................  Answer: 104 mm Hg 18. ............. are the primary sites of gas exchange. (Score 1)  Answer: Alveoli 19. O2 & CO2 are exchanged by ...................... (Score 1)  Answer: Simple diffusion 20. State whether true or false. Rewrite the false statements correctly. (Score 2) a) Gas exchange occurs by simple diffusion mainly based on pressure/concentration gradient. b) Solubility of O2 is 20-25 times higher than that of CO2. c) The pO2 in atmospheric air is lower than the pO2 in the alveoli. d) After oxygenation, pO2 of blood is increased to 95 mm Hg.  Answer a) True. b) False. Solubility of CO2 is 20-25 times higher than that of O2. c) False. The pO2 in atmospheric air is higher than the pO2 in the alveoli. d) True. 21. The given diagram shows the exchange of gases between alveolus and alveolar capillary. (Score 3) a) Identify X and Y. b) Name the physical process involved in gas exchange. c) Mention the factors that favour this process.  Answer a) X= CO2 Y= O2 b) Simple diffusion c) Pressure/ concentration gradient, Solubility of gases, Thickness of membranes, surface area of lungs.
© www.bankofbiology.com All rights reserved. 92 22. Given below is a diagram of a section of an alveolus with a pulmonary capillary. a) Label the layers A, B & C. b) What is the relation between thickness of the diffusion membrane and gas exchange?  Answer a) A= Squamous epithelium of alveolus. B= Basement substance. C= Endothelium of blood capillary. b) As the thickness of the diffusion membrane decreases, gas exchange increases. GAS TRANSPORT (O2 TRANSPORT & CO2 TRANSPORT) 23. Complete the table. (Score 2) Gas transport Types Percentage Oxygen transport Through blood plasma 3% A 97% CO2 transport Through blood plasma B C 20-25% As bicarbonates D  Answer A= As oxyhaemoglobin B= 7% C= As carbamino haemoglobin D= 70% 24. Note the relationship between first two words and fill up the fourth place. Oxygen + haemoglobin: Oxyhaemoglobin CO2 + haemoglobin: ..................  Answer: Carbamino haemoglobin 25. Each haemoglobin molecule can carry .......... oxygen molecules.  Answer: 4 26. Observe the given graph. a. What is depicted by this graph? / Identify the graph. b. Write any 3 factors which can alter this graph. c. What is its significance?  Answer a. Oxygen-Haemoglobin dissociation curve. b. Temperature, PCO2, H+ ion concentration etc. c. It is used to study the effect of PCO2, H+ ion concentration. etc on binding of oxygen with haemoglobin. 27. Oxygen dissociation curve is given below: a) Identify the body parts in which oxyhaemoglobin formation and oxyhaemoglobin dissociation occurs. b) Mention any two factors which are favourable for the dissociation of O2 from oxyhaemoglobin.  Answer a) Oxyhaemoglobin forms in Lung’s alveoli. Oxyhaemoglobin dissociation occurs in Tissues. b) Low PO2, High PCO2, High H+ ions concentration, high temperature. 28. The given graph shows oxygen-haemoglobin dissociation curve. a) What is the nature of curve? b) Find out the pressure at which Haemoglobin is 50% saturated with O2? c) Write any three conditions in the alveoli that favour the formation of oxyhaemoglobin.  Answer a) Sigmoid curve. b) 26 mmHg. c) High PO2, Low PCO2, Low H+ ions concentration, low temperature. 29. Select the enzyme that facilitate the following reaction:
© www.bankofbiology.com All rights reserved. 93 a) Succinic dehydrogenase b. RuBiSCO c) Carbonic anhydrase d. Lipase (Score 1)  Answer: c) Carbonic anhydrase 30. During CO2 transport inside the RBC 70% CO2 combines with the water and form carbonic acid (H2CO3) which soon dissociated to form bicarbonate ions (HCO3 – ) and hydrogen (H+ ) ions. a) Name the enzyme which catalyses this reaction. b) What happens to the 20-25% CO2 that enters into RBC? c) How the remaining 7% CO2 transport occurs? (Score 3)  Answer a) Carbonic anhydrase b) 20-25% of CO2 binds to haemoglobin to form carbamino-haemoglobin. In alveoli, CO2 dissociates from carbamino-haemoglobin. c) 7% of CO2 is dissolved in plasma water to form carbonic acid and carried to lungs. REGULATION OF RESPIRATION, DISORDERS 31. Pneumotaxic centre is located at ............. of the brain.  Answer: Pons 32. Respiratory disorder in which alveolar walls are damaged, due to which respiratory surface is decreased. (Score 1)  Answer: Emphysema 33. Name the different respiratory centres situated in brain. Explain their role in maintaining and moderating the respiratory rhythm. (Score 3)  Answer Respiratory rhythm centre: In medulla oblongata. It regulates respiratory rhythms. Pneumotaxic centre: In Pons. It moderates functions of respiratory rhythm centre. Impulse from this centre reduces the duration of inspiration and thereby alter respiratory rate. Chemosensitive area: Seen adjacent to the rhythm centre. Increase in the concentration of CO2 and H+ activates this centre, which signals rhythm centre. 34. Identify the two true statements from the statements given below and rewrite the two false statements correctly considering the underlined words. (Score 2) a. Respiratory rhythm is maintained by the respiratory centre in the heart. b. Role of oxygen in the regulation of respiratory rhythm is quite insignificant. c. Pneumonia is a chronic disorder due to cigarette smoking. d. Long exposure to so much dust causes inflammation leading to fibrosis of lungs.  Answer a. False. Respiratory rhythm is maintained by the respiratory centre in the brain. b. True. c. False. Emphysema is a chronic disorder due to cigarette smoking. d. True. 35. Asthma and emphysema are two disorders of the human respiratory system. Mention their causes and symptoms. (Score 2)  Answer Asthma: Difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles. Emphysema: Damage of alveolar walls. Major cause is cigarette smoking. Want More...? Click Here for Plus 1 and Plus 2 Exam Special materials