Q3. The branching network of bronchi, bronchioles, and ______ comprise the lungs.
Correct Answer: (b)
The branching network of bronchi, bronchioles and alveoli comprise the lungs.
Q4. Identify correct matches for 'Volumes': (i) TV = 500 mL. (ii) RV = 1100-1200 mL. (iii) VC = TV + IRV + ERV.
Correct Answer: (a)
Standard volumes and VC formula.
Q5. The Italian anatomist Alfonso Corti began his scientific career studying which system in reptiles?
Correct Answer: (b)
Alfonso Corti began his career studying the cardiovascular systems of reptiles.
Q6. Branchial respiration refers to the use of:
Correct Answer: (c)
Respiration using gills is called branchial respiration.
Q7. Assertion: Alveoli are the primary sites of exchange of gases.
Reason: They are irregular-walled and vascularised bag-like structures.
Correct Answer: (b)
Both are true descriptions, but its structure is not the only reason it's the 'primary site' (exchange also occurs at tissues).
Q8. Match the component of the diffusion membrane (Inside to Outside):
Layer
Name
A. Layer 1
(I) Squamous epithelium of alveoli
B. Layer 2
(II) Endothelium of alveolar capillaries
C. Layer 3
(III) Basement substance
Correct Answer: (a)
Correct layers of diffusion membrane as per section 14.3.
Q9. Assertion: Expiration occurs when intra-pulmonary pressure is higher than atmospheric pressure.
Reason: Relaxation of the diaphragm and intercostal muscles reduces thoracic volume.
Correct Answer: (a)
Relaxation causes volume decrease, which increases pressure and forces air out.
Q10. Assertion: Solubility of CO2 is 20-25 times higher than that of O2.
Reason: The amount of CO2 that can diffuse through the diffusion membrane per unit difference in partial pressure is much higher.
Correct Answer: (a)
High solubility directly correlates to high diffusion rate across the membrane.
Q11. Match the partial pressure (Atmosphere):
Gas
mm Hg
A. O2
(I) 0.3
B. CO2
(II) 159
Correct Answer: (a)
Atmos air: pO2=159, pCO2=0.3.
Q12. The respiratory rhythm centre is primarily located in the ______ region of the brain.
Correct Answer: (c)
A specialized centre in the medulla called the respiratory rhythm centre is primarily responsible for regulation.
Q13. Assertion: Trachea is supported by incomplete cartilaginous rings.
Reason: It prevents the trachea from collapsing.
Correct Answer: (b)
Both are true (functional anatomy), but not explicitly detailed as the reason in the provided snippet.
Q14. Match the scientists' focus:
Scientist
Discovery
A. Alfonso Corti
(I) Basilar membrane hair cells
B. Blackman
(II) Law of limiting factors (Unit Intro)
Correct Answer: (a)
Historical contributions mentioned in unit/chapter.
Q15. Match the gas transport amount:
Blood Type
Amount Delivered
A. 100ml Oxygenated blood
(I) 5ml O2
B. 100ml Deoxygenated blood
(II) 4ml CO2
Correct Answer: (a)
100ml blood: 5ml O2 to tissue, 4ml CO2 to alveoli.
Q16. The lungs are situated in an air-tight chamber called the:
Correct Answer: (b)
The lungs are situated in the thoracic chamber.
Q17. The cartilaginous box in the human respiratory system which helps in sound production is the:
Correct Answer: (c)
Larynx is a cartilaginous box which helps in sound production and hence called the sound box.
Q18. Every 100 ml of deoxygenated blood delivers approximately ______ ml of CO2 to the alveoli.
Correct Answer: (a)
Every 100 ml of deoxygenated blood delivers approximately 4 ml of CO2 to the alveoli.
Q19. Regarding 'Expiratory Reserve Volume' (ERV): (i) Additional volume of air a person can expire forcibly. (ii) Average 1000 to 1100 mL. (iii) It is always larger than IRV.
Correct Answer: (a)
IRV (2500-3000) is much larger than ERV (1000-1100).
Q20. The chemosensitive area adjacent to the rhythm centre is highly sensitive to:
Correct Answer: (b)
The chemosensitive area is highly sensitive to CO2 and hydrogen ions.
Q21. Inspiration occurs when there is a ______ pressure in the lungs with respect to atmospheric pressure.
Correct Answer: (b)
Inspiration occurs if there is a negative pressure in the lungs with respect to atmospheric pressure.
Q22. Which statements about 'CO2 Transport' are correct? (i) 70% as bicarbonate. (ii) 20-25% by RBCs. (iii) 7% dissolved in plasma.
Correct Answer: (a)
Standard distribution of CO2 transport.
Q23. Assertion: Diffusion of gases occurs in the alveolar region only.
Reason: Alveoli and their ducts form the exchange part of the respiratory system.
Correct Answer: (a)
Exchange only happens in the exchange part (alveoli).
Q24. Match the partial pressure in mm Hg (Blood Oxygenated):
Gas
pO2/pCO2
A. O2
(I) 40
B. CO2
(II) 95
Correct Answer: (a)
Oxy blood: pO2=95, pCO2=40.
Q25. Which statement about 'Conducting Part' is correct? (i) It consists of nostrils to terminal bronchioles. (ii) It is the site of actual diffusion of O2 and CO2. (iii) It clears air from foreign particles.
Correct Answer: (a)
Diffusion (ii) happens in the exchange part, not conducting part.
Q26. Emphysema is a chronic disorder primarily caused by:
Correct Answer: (b)
One of the major causes of emphysema is cigarette smoking.
Q27. Which disorder is characterized by inflammation of bronchi and bronchioles causing wheezing?
Correct Answer: (b)
Asthma is a difficulty in breathing caused by inflammation of bronchi and bronchioles.
Q28. Assertion: RBCs are nucleated in some organisms but not mammals.
Reason: Mature human erythrocytes lack a nucleus.
Correct Answer: (a)
Human RBCs being non-nucleated is a specific fact, but doesn't explain the state of other organisms.
Q29. Earthworms use which structure for respiration?
Correct Answer: (c)
Earthworms use their moist cuticle for the exchange of gases.
Q30. The site of actual diffusion of O2 and CO2 between blood and atmospheric air is the:
Correct Answer: (b)
Exchange part is the site of actual diffusion of O2 and CO2.
Q31. The process of exchange of O2 from the atmosphere with CO2 produced by the cells is called:
Correct Answer: (b)
The exchange of O2 from the atmosphere with CO2 produced by cells is called breathing, commonly known as respiration.
Q32. Regarding 'Partial Pressure', which is true? (i) pO2 in alveoli is 104 mm Hg. (ii) pCO2 in alveoli is 40 mm Hg. (iii) pO2 in oxygenated blood is 95 mm Hg.
Correct Answer: (a)
All values match Table 14.1.
Q33. Regarding 'Haemoglobin' binding: (i) Favouring factors in alveoli: High pO2, low pCO2, low H+, lower temp. (ii) Favouring dissociation in tissues: Low pO2, high pCO2, high H+, high temp.
Correct Answer: (a)
Environmental conditions for Hb-O2 affinity.
Q36. Identify the correct features of the 'Diffusion Membrane': (i) Thin squamous epithelium of alveoli. (ii) Endothelium of alveolar capillaries. (iii) Total thickness is much less than a millimetre.
Correct Answer: (a)
Anatomical components and thickness of the membrane.
Q37. Additional volume of air a person can inspire by a forcible inspiration is:
Correct Answer: (b)
Inspiratory Reserve Volume (IRV) is for forcible inspiration.
Q38. Identify the correct phylum/group being described: (i) High pO2, low pCO2 in alveoli. (ii) Low pO2, high pCO2 in tissues. (iii) Diffusion occurs along concentration gradients.
Correct Answer: (a)
Conditions favoring diffusion are part of gas exchange.
Q39. Assertion: Vital Capacity is higher than Tidal Volume.
Reason: Vital Capacity includes ERV, TV, and IRV.
Correct Answer: (a)
Summation of multiple volumes makes the capacity larger.
Q40. Tidal Volume (TV) for a healthy man is approximately ______ mL per minute.
Correct Answer: (c)
A healthy man can inspire or expire approximately 6000 to 8000 mL of air per minute.
Q43. Which statements about 'Epiglottis' are correct? (i) Thin elastic cartilaginous flap. (ii) Prevents entry of food into larynx. (iii) Covers glottis during swallowing.
Correct Answer: (a)
Function and structure of the epiglottis.
Q44. Match the volumes in sequence of size (Smallest to Largest):
Rank
Volume
1st
TV (500)
2nd
ERV (1000-1100)
3rd
RV (1100-1200)
4th
IRV (2500-3000)
Correct Answer: (a)
Standard volume ranges in mL.
Q45. The enzyme required for the transport of CO2 as bicarbonate is:
Correct Answer: (b)
RBCs contain a high concentration of carbonic anhydrase for this reaction.
Q46. Which of the following is correct? (i) RBCs carry 97% O2. (ii) RBCs carry 20-25% CO2. (iii) RBCs contain carbonic anhydrase.
Correct Answer: (a)
The roles and enzymatic content of RBCs in gas transport.
Q47. Match the partial pressure in mm Hg (Blood Deoxygenated):
Gas
pO2/pCO2
A. O2
(I) 45
B. CO2
(II) 40
Correct Answer: (a)
Deoxy blood: pO2=40, pCO2=45.
Q48. CO2 is carried by haemoglobin as:
Correct Answer: (b)
CO2 is carried by haemoglobin as carbamino-haemoglobin (20-25%).
Q49. Which muscles, along with the diaphragm, help in generation of pressure gradients for breathing?
Correct Answer: (c)
The diaphragm and intercostal muscles help in generating pressure gradients.
Q50. Assertion: Every 100 ml of oxygenated blood can deliver around 5 ml of O2 to the tissues.
Reason: Oxyhaemoglobin is formed in the alveoli and dissociates in the tissues.
Correct Answer: (a)
The delivery of O2 is a result of the formation and subsequent dissociation of oxyhaemoglobin.
Q51. The pneumotaxic centre, which can moderate the functions of the rhythm centre, is in the:
Correct Answer: (b)
Another centre present in the pons region of the brain is called the pneumotaxic centre.
Q52. Which part of the respiratory system humidifies and brings the air to body temperature?
Correct Answer: (b)
The conducting part clears air from particles, humidifies it, and brings it to body temperature.
Q53. Assertion: Inspiration is initiated by the contraction of diaphragm.
Reason: Contraction of the diaphragm increases the volume of the thoracic chamber in the dorso-ventral axis.
Correct Answer: (c)
Reason is false because diaphragm contraction increases volume in the antero-posterior axis, not dorso-ventral.
Q54. Match the respiratory volumes with their average values:
Q55. The trachea divides into right and left primary bronchi at the level of which vertebra?
Correct Answer: (b)
Trachea divides at the level of the 5th thoracic vertebra.
Q56. Assertion: The conducting part clears the air from foreign particles.
Reason: It includes the nostrils up to the terminal bronchioles.
Correct Answer: (b)
Both are true, but its extent doesn't explain how it clears particles (which is done by mucus/cilia).
Q57. Which statements about 'Alveoli' are correct? (i) Site of gas exchange. (ii) Surrounded by network of capillaries. (iii) Have thin squamous epithelium.
Correct Answer: (a)
Standard alveolar anatomy and role.
Q58. Assertion: Emphysema is a chronic disorder.
Reason: One of the major causes is cigarette smoking.
Correct Answer: (b)
Cigarette smoking causes the damage, which makes it chronic.
Q59. Occupational respiratory disorders like fibrosis are caused by long exposure to:
Correct Answer: (c)
Industries involving grinding or stone-breaking produce dust that causes fibrosis.
Q60. Identify correct steps in 'Respiration': (i) Breathing. (ii) Diffusion across alveolar membrane. (iii) Transport by blood. (iv) Utilization of O2 by cells.
Correct Answer: (a)
Sequence of events from section 14.1.1 list.
Q61. Assertion: CO2 diffuses from tissues to blood.
Reason: pCO2 is higher in tissues (45 mm Hg) than in deoxygenated blood (40 mm Hg is incorrect; it's 45).
Correct Answer: (a)
Deoxy blood and tissues have the same pCO2 (45), but tissues are the source, so it moves to blood.
Q62. Assertion: Tidal volume is about 500 mL.
Reason: It is the volume of air inspired or expired during a normal respiration.
Correct Answer: (a)
The definition explains the volume.
Q63. Assertion: Carbonic anhydrase is found in RBCs and plasma.
Reason: It helps in the conversion of CO2 and water to bicarbonate.
Correct Answer: (a)
The enzyme's presence allows the specific chemical transport mechanism.
Q64. Tracheal tubes as a respiratory mechanism are found in:
Correct Answer: (b)
Insects have a network of tubes (tracheal tubes) to transport atmospheric air within the body.
Q65. Match the O2 delivery factors:
Factor
Effect on Hb Binding
A. High pO2
(I) Favour binding
B. High pCO2
(II) Favour dissociation
C. High H+
(III) Favour dissociation
Correct Answer: (a)
Conditions in Alveoli (I) vs Tissues (II/III).
Q66. Which of the following vertebrates uses gills for respiration?
Correct Answer: (c)
Among vertebrates, fishes use gills.
Q67. The partial pressure of CO2 (pCO2) in deoxygenated blood is:
Correct Answer: (b)
As per Table 14.1, pCO2 in deoxygenated blood is 45 mm Hg.
Q68. Assertion: Haemoglobin can carry a maximum of four molecules of O2.
Reason: Haemoglobin is a red coloured iron containing pigment.
Correct Answer: (a)
Both are true, but the color/iron doesn't explain the 'four molecules' stoichiometric capacity.
Q76. Which of the following is being described by the given statements? (i) These are located in the thoracic chamber. (ii) They are covered by a double layered pleura. (iii) Their total volume can be Accommodation in the end of forced inspiration.
Correct Answer: (b)
These describe the location, covering, and capacity (TLC) of the lungs.
Q77. Select correct statements for 'Regulation of Respiration': (i) Respiratory rhythm centre is in medulla. (ii) Pneumotaxic centre is in pons. (iii) O2 has a major role in regulation.
Correct Answer: (a)
O2 role (iii) is insignificant.
Q78. Which of the following describes 'Asthma' correctly? (i) Difficulty in breathing. (ii) Causes wheezing. (iii) Due to inflammation of bronchi and bronchioles.
Correct Answer: (a)
Full clinical description of asthma provided.
Q79. Lungs are covered by a double-layered membrane called:
Correct Answer: (c)
Lungs are covered by a double layered pleura.
Q80. The solubility of CO2 is ______ times higher than that of O2.
Correct Answer: (c)
The solubility of CO2 is 20-25 times higher than that of O2.
Q81. Assertion: A sigmoid curve is obtained when percentage saturation of haemoglobin with O2 is plotted against pO2.
Reason: Sigmoid curve indicates that binding of the first O2 molecule facilitates the binding of others.
Correct Answer: (b)
Both are true, but the NCERT text only provides the fact of the curve, not the chemical cooperativity reason explicitly.
Q82. Assertion: The pneumotaxic centre is in the pons.
Reason: It can reduce the duration of inspiration.
Correct Answer: (b)
Both are true, but location does not explain function.
Q83. Match the capacity with its constituent volumes:
Correct Answer: (a)
TLC includes RV, ERV, TV and IRV, which is Vital Capacity + Residual Volume.
Q85. Assertion: Occupational respiratory disorders cause serious lung damage.
Reason: Long exposure to dust can lead to fibrosis (proliferation of fibrous tissues).
Correct Answer: (a)
Fibrosis reduces lung function and is the pathological cause of damage in these disorders.
Q86. Match the vertebrate with its respiratory organ:
Q87. The volume of air involved in breathing movements can be estimated using a:
Correct Answer: (b)
A spirometer helps in clinical assessment of pulmonary functions.
Q88. The diffusion membrane is made up of how many major layers?
Correct Answer: (c)
The diffusion membrane is made up of three major layers: squamous epithelium, endothelium, and basement substance.
Q89. Match the transport mechanism with the percentage of gas:
Column-I (Gas & State)
Column-II (Percentage)
A. O2 by RBCs
(I) 70%
B. O2 in dissolved plasma
(II) 20-25%
C. CO2 as Bicarbonate
(III) 97%
D. CO2 by RBCs
(IV) 3%
Correct Answer: (a)
O2 RBC: 97%; O2 Plasma: 3%; CO2 Bicarb: 70%; CO2 RBC: 20-25%.
Q90. On average, a healthy human breathes ______ times per minute.
Correct Answer: (b)
On an average, a healthy human breathes 12-16 times/minute.
Q91. During swallowing, the entry of food into the larynx is prevented by a thin elastic cartilaginous flap called:
Correct Answer: (b)
Epiglottis prevents the entry of food into the larynx.
Q92. Assertion: The role of oxygen in the regulation of respiratory rhythm is quite insignificant.
Reason: Respiratory rhythm is mainly regulated by CO2 and H+ concentration.
Correct Answer: (a)
The neural centers and chemosensitive areas prioritize CO2 and pH over O2 levels.
Q93. Regarding 'Oxygen Dissociation Curve', identify correct statements: (i) It is sigmoid shaped. (ii) Plot of % saturation of Hb with O2 vs pO2. (iii) High H+ shift it to the right (dissociation).
Correct Answer: (a)
High H+ and pCO2 favor dissociation, shifting curve to right.
Q94. Which of the following is true for 'Solubility'? (i) CO2 is more soluble than O2. (ii) Solubility is 20-25 times higher. (iii) This increases CO2 diffusion rate across membranes.
Correct Answer: (a)
Relationship between solubility and diffusion.
Q95. Which are correct for 'Larynx'? (i) Cartilaginous box. (ii) Helps in sound production. (iii) Called the sound box.
Correct Answer: (a)
Structure and function of larynx.
Q96. Assertion: The diffusion membrane is less than a millimetre thick.
Reason: All factors in our body are favourable for diffusion of O2 from alveoli to tissues.
Correct Answer: (a)
Thickness is a factor, and diffusion is favorable, but 'thickness' is only one of the factors.
Q97. What percentage of O2 is transported by RBCs in the blood?
Correct Answer: (d)
About 97 per cent of O2 is transported by RBCs.
Q98. Vital Capacity (VC) is the sum of:
Correct Answer: (c)
Vital Capacity includes ERV, TV and IRV.
Q99. Regarding 'Pleura', which is true? (i) Double layered membrane covering lungs. (ii) Contains pleural fluid. (iii) Outer layer in contact with thoracic lining.
Correct Answer: (a)
Description from section 14.1.1.
Q100. The partial pressure of oxygen (pO2) in the alveoli is ______ mm Hg.
Correct Answer: (b)
As per Table 14.1, pO2 in alveoli is 104 mm Hg.
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