This set of Class 11 Biology Multiple Choice Questions & Answers (MCQs) focuses on “Mechanism of Breathing-2” for NEET Preparation.
1. Which of the following is the most important muscular structure in respiratory system of human?
a) External intercoastal muscle
b) Internal intercoastal muscle
c) Diaphgram
d) Vertebral column
View Answer
Explanation: Diaphgram is the most important muscular structure in respiratory system of human. At the time of inspiration, diaphgram contracts leading to increase in thoracic volume whereas during expiration it relaxes causing decrease in thoracic volume.
2. Air that remains in lungs after most powerful expiration is _______
a) inspiratory air
b) residual air
c) dead space air
d) tidal air
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Explanation: Residual air is the volume of air remaining in the lungs even after most forceful expiration. It cannot be expelled out of the lungs. Its value on an average in adult man is approximately 1200 ml.
3. Contraction in diaphgram causes increase in thoracic volume in the _____
a) dorso-ventral axis
b) antero-posterior axis
c) dorso-posterior axis
d) antero-ventral axis
View Answer
Explanation: At the time of inspiration diaphgram contracts leading to increase in thoracic volume in the anterior posterior axis. Whereas movement of sternum causes increment in antero-ventral direction.
4. Where is the respiratory rhythm center is located?
a) Medulla region
b) Aortic arch
c) Pons region
d) Carotid artery
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Explanation: The respiratory rhythm center in the Medulla is primarily responsible for the regulation. Dorsal respiratory group(DRG) generate the basic respiratory rhythm whereas the ventral respiratory(VRG) which remains inactive during normal respiration.
5. What happens to RBC of human blood at high altitude?
a) Decrease in size
b) Decrease in number
c) Increase in size
d) Increase in number
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Explanation: At high altitude oxygen pressure is lower thus lungs have to take in more oxygen to fulfill the demands of the body. Therefore, an increase in RBC helps to transport more oxygen to the body parts.
6. Strength of inspiration and expiration can be increased with the help of_______
a) abdominal muscles
b) external intercoastal muscle
c) diaphragm
d) internal intercoastal muscle
View Answer
Explanation: Abdominal muscles can increase the strength of inspiration and expiration. This type of breathing is also known as forceful breathing and can be found in pregnant women.
7. Pneumotaxic centre is located in ________
a) pons
b) cerebrum
c) medulla
d) cerebellum
View Answer
Explanation: The Pneumotaxic centre is located on pons. It is called switch off point of inspiration. Neural signal from this centre can reduce the duration of inspiration and thereby alter the respiratory rate.
8. Which does not occur on normal inspiration?
a) Contraction in diaphragm
b) Contraction in external intercoastal muscle
c) Contraction in internal intercoastal muscle
d) Sternum moves upward
View Answer
Explanation: At the time of inspiration diaphgram and external intercoastal muscle contracts leading to increase in thoracic volume. Also, ribs move outward and sternum moves upward.
9. Dead space air is _______
a) 150 CC
b) 350 CC
c) 500 CC
d) 1500 CC
View Answer
Explanation: Dead space air is 150 CC. Dead space air represents the volume of air that does not participate in the gaseous exchange and remains in the lungs. It can’t be expired or inspired or altered.
10. The signal for voluntary muscle for forced breathing starts in ______
a) medulla
b) cerebrum
c) pons
d) cerebellum
View Answer
Explanation: The signal for voluntary muscle for forced breathing starts in cerebrum. Cerebrum is the control center of all the voluntary actions of the body. In forceful inspiration or expiration, signals are generated through this.
Sanfoundry Global Education & Learning Series – Biology – Class 11.
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