PrepBharat

1. Even when air being absent, the human trachea does not collapse due to the presence of
a) Bony rings
b) Turgid pressure
c) Chitinous rings
d) Cartilaginous rings

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2. The chambers formed dorsally by the vertebral column, ventrally by sternum, laterally by ribs and on the lower side by dome-shaped diaphragm is
a) Abdominal chamber
b) Cranial chamber
c) Pelvic chamber
d) Thoracic chamber

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3. Select the incorrect statement from the following:
a) Pleural fluid reduces friction on the lung surface.
b) The anatomical setup of lungs in thorax is such that any change in the volume of the thoracic cavity will be reflected in the lung (pulmonary) cavity. Such an arrangement is essential for breathing, as we cannot directly alter the pulmonary volume.
c) The tracheae, primary, secondary and tertiary bronchi and initial bronchioles are supported by complete cartilaginous rings.
d) During swallowing, the glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the larynx.

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4. During inspiration
a) Diaphragm and external intercostals muscle relax.
b) Diaphragm and internal intercostals muscles relax.
c) Diaphragm and external intercostals muscles contract.
d) Diaphragm and internal intercostals muscles contract.

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5. During inspiration, the diaphragm
a) Relaxes to become dome-shaped
b) Contracts and flattens
c) Expands
d) Shows no change

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6. Expiration involves
a) Relaxation of diaphragm and intercostals muscles
b) Contraction of diaphragm and intercostals muscles
c) Contraction of diaphragm muscles
d) Contraction of intercostals muscles

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7. Which two of the following changes (a to d) usually tend to occur in plain dwellers when they move to higher altitudes (3500 m or more)
(i) Increase in red blood cell size
(ii) Increase in red blood cell production
(iii) Increase in breathing rate
(iv) Increase in thrombocyte count
a) Both (iii) and (iv)
b) Both (i) and (iv)
c) Both (iii) and (i)
d) Both (ii) and (iii)

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8. In alveolar air, the partial pressure of CO₂ is
a) 40 mm Hg
b) 44 mm Hg
c) 46 mm Hg
d) 42 mm Hg

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9. Arrange the following steps of respiration properly:
1. Breathing or pulmonary ventilation by which atmospheric air is drawn in and CO₂ rich alveolar air is released out.
2. Diffusion of gases ( \[O_{2}\] and \[CO_{2}\]   ) across alveolar membrane.
3. Transport of gases by the blood.
4. Diffusion of \[O_{2}\] and \[CO_{2}\] between blood and tissues.
5. Utilization of \[O_{2}\] , by the cells for catabolic reactions and resultant release of CO2.
a) 1,2,3,4,5
b) 1,3,2,5,4
c) 5,4,3,1,2
d) 3,4,5,2,1

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10. Expiratory muscles contract at the time of
a) Deep inspiration
b) Normal inspiration and expiration
c) Forceful expiration
d) Muscular expansion of lungs

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