Tag: breathing and exchange of gas

Questions Related to breathing and exchange of gas

During inspiration, the pressure of air is maximum in ___________.

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Trachea

  2. Bronchus

  3. Alveoli

  4. Environment

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Correct Option: A

In negative pressure breathing, inhalation results from:

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. forcing air from the throat down into the lungs

  2. contracting the diaphragm

  3. relaxing the muscles of the rib cage

  4. contracting the abdominal muscles

Show answer
Correct Option: B
Explanation:

During the process of inhalation, the lung volume expands as a result of contraction of the diaphragm & intercostal muscles, thoracic cavity expands, due to this increase in volume, the pressure is decreased.

So, the correct option is 'contracting the diaphragm'.

During expiration the diaphragm becomes

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. dome-shaped

  2. oblique

  3. concave

  4. flattened.

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Correct Option: A
Explanation:

When the internal intercostal muscles contract and diaphragm relax, the ribs move .downward and inward and diaphragm becomes convex {dome shaped), thus decreasing the volume of thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside. This will cause the air to move out (expiration).

After forceful inspiration, the amount of air that can be breathed out by maximum forced expiration is equal to

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV) + Tidal Volume (TV) + Residual Volume (RV)

  2. IRV + RV + ERV

  3. IRV + TV + ERV

  4. TV + RV + ERV

Show answer
Correct Option: C
Explanation:

Vital capacity is the maximum volume of air a person can breathe in after a forced expiration or the maximum volume of air a person can breathe out after a forced inspiration.This equals the inspiratory reserve volume (IRV) + expiratory reserve volume (ERV) + tidal volume (TV). Its value is 3400 mL - 4800 mL..

Read the following four statements (i) - (iv) with certain mistakes in two of them.
(i) A water breather expends much more energy in ventilating its respiratory surface than an air-breathing one.
(ii)   Lungs become empty after forceful expiration.
(iii) Exchange of gases in the lungs is interrupted during expiration.
(iv) Respiratory movements are controlled by $CO _{2}$ concentration of arterial blood.
Which of the above two statements have mistakes?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. (i) and (iv)

  2. (ii) and (iii)

  3. (i)and(ii)

  4. (iii) and (iv)

Show answer
Correct Option: B
Explanation:

 Corrected statements:

(ii) Lungs do not become empty after a forceful expiration.

(iii) The exchange of gases in the lungs is not interrupted during expiration.

So, the correct answer is '(ii) and (iii)'.

Mark the correct pair of muscles involved in the normal breathing in humans.

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. External and internal intercostal muscles

  2. Diaphragm and abdominal muscles

  3. Diaphragm and external intercostal muscles

  4. Diaphragm and intercostal muscles

Show answer
Correct Option: D
Explanation:
Breathing involves two stages : inspiration during which atmospheric air is drawn in and expiration by which the alveolar air is released out. Inspiration can occur if the. pressure within the lungs (intra-pulmonary pressure) is less than the atmospheric pressure, i.e., there is a negative pressure in the lungs with respect to atmospheric pressure. Similarly, expiratibn takes place when the intra-pulmonary pressure is higher than the atmospheric pressure. The diaphragm and a specialised set of muscles-external and internal intercostals between the ribs, help in generation of such gradients.
So, the correct answer is 'Diaphragm and intercostal muscles'.

Which of the following statement is correct?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. During inspiration external intercoastal muscles and diaphragm contract

  2. Coryza is caused by human corona virus

  3. Cyanosis means collapse of alveoli

  4. Eupnea is slow breathing

Show answer
Correct Option: A
Explanation:

During inspiration external intercoastal muscles and diaphragm contract because it allows air to be moved into the lungs and requires the contraction of various musceles; the diaphragm and external intercoastal muscles contract.

Inspiration is initiated by the contraction of?

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. External intercostal muscles

  2. Internal intercostal muscles

  3. Diaphragm

  4. Both a and b

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Correct Option: C

Read the following sentences carefully and select the incorrect one.

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. During expiration, $pO _2$ of expired air is more than alveolar air but less than atmospheric air

  2. During expiration, $pO _2$ of expired air is less than $pCO _2$ of alveolar air but more than $pCO _2$ of atmospheric air

  3. Sum of partial pressure of all gases at sea level is $760 mm Hg$

  4. The partial pressure of $O _2$ and $CO _2$$ in the systemic veins is same as that in pulomonary vein.

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Correct Option: A
Explanation:

Sum of the partial pressure of all gases is 760 mm of Hg.

The partial pressure of oxygen and carbon dioxide is same in systematic vein since they are continuous.
During expiration, $pO _2$ of experience air is less than $pCO _2$ of alveolar air but less than atmospheric air as the atmosphere has a high concentration of oxygen.
During expiration, $pO _2$ of expired air is less than alveolar air and atmospheric air.
So the correct answer is 'During expiration $pO _2$ of expired air is more than alveolar air but less than atmospheric air'.

Oxygen in expired air

zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

  1. 10%

  2. 16%

  3. 19%

  4. 4%

Show answer
Correct Option: B
Explanation:

The amount gases in exhaled air are 4% to 5% by volume more carbon dioxide and 4% to 5% by volume less oxygen than was inhaled. This expired air typically composed of: 78.04% nitrogen; 13.6% - 16% oxygen; 4% - 5.3% carbon dioxide; 1% other gases.