Topic: Breathing and Exchange of Gases (Test 1)



Topic: Breathing and Exchange of Gases
Q.1
Tracheal tube divides into right and left bronchi at the level of :
A. 5th thoracic vertebra
B. 7th thoracic vertebra
C. 4th thoracic vertebra
D. 6ththoracic vertebra
Answer : Option A
Explaination / Solution:

Trachea divides at the level of 5th thoracic vertebra into a right and left primary bronchi.

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Q.2
Vital capacity of our lungs include all of the following except :
A. ERV
B. TV
C. RV
D. IRV
Answer : Option C
Explaination / Solution:

Vital capacity includes ERV, TV and IRV or the maximum volume of air a person can breathe out after a forced inspiration.

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Q.3
Skin is the only respiratory organ in :
A. larvae of mosquitoes
B. Peripatus
C. Hirudinaria granulosa
D. Ranatigrina
Answer : Option C
Explaination / Solution:

There are no special respiratory organs in Hirudinaria. In addition to its primary role of a protective covering, the skin also serves a respiratory function. It is provided with a rich supply of haemocoelomic fluid in an extensive system of capillaries and capillary loops, which penetrate into the spaces between the inner ends of the epidermal cells.

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Q.4
Pharynx is the common passage for food and air but still food do not enter into the windpipe due to the presence of
A. Epiglottis
B. valve of windpipe
C. Frenulum
D. Glottis
Answer : Option A
Explaination / Solution:

The epiglottis is a leaf-shaped flap of cartilage located behind the tongue, at the top of the larynx, or voice box. The main function of the epiglottis is to seal off the windpipe during eating, so that food is not accidentally inhaled.

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Q.5
The value of TV is about 500 ml for an average adult human male but only some part of it enters lung alveoli and rest of it fills respiratory passage. What should be the distribution ratio for alveolar volume /respiratory passage volume:
A. 2:3
B. 1:1
C. 7:3
D. 3:7
Answer : Option C
Explaination / Solution:

Tidal volume (TV) = volume moved in one breath. Normal = 500 ml

  • About 70% of TV reaches alveoli (350 ml) Only this amount is involved in gas exchange
  • 30% in airways =respiratory passage (anatomical dead space)

So ratio = 350:150= 7:3


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Q.6
The exposure of carbon monoxide to animals
A. Reduces carbon dioxide transport
B. Reduces oxygen transport
C. Destroys haemoglobin
D. Increases carbon dioxide transport
Answer : Option C
Explaination / Solution:

The toxicity in animals is caused by the extraordinary affinity of carbon monoxide for haemoglobin which is responsible for the oxygen transport (approx. 250 times greater affinity of carbon monoxide compared to oxygen.because of higher affinity it destroys the haemoglobin.

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Q.7
Ram suffers punctures in his chest cavity without any damage to the lungs in an accident. It results in
A. Rapid increase in breathing rate
B. Reduction in breathing rate
C. No effect in breathing
D. Cessation of breathing
Answer : Option D
Explaination / Solution:

haemopneumothorax, is a medical term describing the combination of two conditions: pneumothorax, or air in the chest cavity, and hemothorax (also called hæmothorax), or blood in the chest cavity. A hemothorax, pneumothorax or both can occur if the chest wall is punctured. Becauseof punctured chest wall, the lungs cannot expand, the pressure in the lungs never drops and no air is pulled into the bronchi. Respiration is not possible.

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Q.8
Which one of the following is wrong statement with respect to the functions of respiratory system?
A. Diffusion of gases
B. Cleans up the air
C. Humidifies the air
D. Warms up the air
Answer : Option B
Explaination / Solution:

The function of respiratory system does not deal with the cleaning up of the air.

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Q.9
Match the following:

respiratory volume
a) RV
b) ERV
c) TV
d)IRV

value (in ml)
i) 1000 - 1100
ii) 6000 - 8000
iii) 2500 - 3000
iv) 1100 - 1200
A. a)-ii, b)-iii, c)-i, d)-iv
B. a)-ii, b)-i, c)-iv, d)-iii
C. a)-iii, b)-iv, c)-ii, d)-i
D. a)-iv, b)-i, c)-ii, d)-iii
Answer : Option D
Explaination / Solution:

TV isapprox. 500 mL., i.e., a healthy man caninspire or expire approximately 6000 to 8000mL of air per minute. IRV averages 2500mL to 3000 mL.ERV averages 1000mL to 1100 mL. RV averages 1100 mL to 1200 mL.

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Q.10
Respiration in insects is direct due to exchange of gases
A. Directly with coelomic fluid
B. Directly with the air outside through body surface
C. By tracheal tubes directly with haemocoel which then exchange with tissues.
D. Directly with the air in tubes
Answer : Option C
Explaination / Solution:

Insects have spiracles on their exoskeletons to allow air to enter the trachea. In insects, the tracheal tubes primarily deliver oxygen directly into the insects' tissues. The spiracles can be opened and closed in an efficient manner to reduce water loss. This is done by contracting closer muscles surrounding the spiracle.

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