Biology

Respiration and Gas Exchange

958 Questions

Access a targeted set of questions on respiration and gas exchange for competitive exams. Topics include lung volumes, the mechanism of breathing, and respiratory anatomy. Understanding these physiological processes is essential for scoring well.

Lung volumes and capacitiesBreathing mechanismsRespiratory anatomyGas exchange processes

Respiration and Gas Exchange Questions

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

During inspiration.

  1. Diaphragm and external intercostal muscles relax

  2. Diaphragm and internal intercostal muscles relax

  3. Diaphragm and external intercostal muscles contract

  4. Diaphragm and internal intercostal muscles contract
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Inspiration is an active process involving the contraction of the diaphragm (moving downward) and the external intercostal muscles (lifting the ribs).

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

Which is correct?

  1. During inspiration, external intercostal muscles and diaphragm contract

  2. Cyanosis means collapse of alveoli

  3. Eupnoea is slow breathing

  4. Coryza is caused by human corona virus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option A correctly describes the active phase of breathing. The other options are incorrect: cyanosis is a bluish discoloration due to low oxygen, eupnoea is normal breathing, and coryza is typically caused by rhinoviruses.

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

Read the following statements regarding mechanism of respiration and choose the correct option.
$1$. Inspiration occurs only when there is negative pressure in the lungs with respect to atmosphere
$2$. Expiration takes place only when intrapulmonary pressure is lower than atmospheric pressure
$3$. Pressure gradients are generated with the help of diaphragm and intercostal muscles
$4$. Inspiration is initiated by relaxation of diaphragm
$5$. Contraction of diaphragm reduces pulmonary volume and increases intrapulmonary pressure causing expiration.

  1. $1, 2$ and $5$ correct
  2. $2$ only correct
  3. $2, 5$ correct
  4. $1, 3$ correct
  5. $1, 4$ correct
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement 1 is correct (negative pressure is required). Statement 3 is correct (muscles create the pressure gradient). Statements 2, 4, and 5 are incorrect because expiration is passive (relaxation) and contraction of the diaphragm increases volume, not reduces it.

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

With conscious efforts one can.

  1. Breathe out air totally without oxygen

  2. Breathe in and out by moving diaphragm alone without moving ribs at all

  3. Breathe out air through eustachian tube by closing both nose and mouth

  4. Empty the lungs completely by breathing out all air out of them
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The diaphragm and intercostal muscles are skeletal muscles, allowing for some conscious control. One can choose to breathe using only the diaphragm (abdominal breathing) or only the ribs (thoracic breathing).

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

Which of the following is the most appropriate in normal circumstances?

  1. During inspiration the intrapulmonary pressure is less than the atmospheric pressure

  2. During expiration the intrapulmonary pressure is less than the atmospheric pressure

  3. During inspiration the intrapulmonary pressure is more than the atmospheric pressure

  4. During expiration the intrapulmonary pressure is equal to atmospheric pressure
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For air to flow into the lungs during inspiration, the intrapulmonary pressure must be lower than the atmospheric pressure, creating a pressure gradient.

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

In negative pressure breathing, inhalation results from:

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.

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

During expiration the diaphragm becomes

  1. dome-shaped

  2. oblique

  3. concave

  4. flattened.
Reveal answer Fill a bubble to check yourself
A Correct answer
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).

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

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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..

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

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?

  1. (i) and (iv)

  2. (ii) and (iii)

  3. (i)and(ii)

  4. (iii) and (iv)
Reveal answer Fill a bubble to check yourself
B Correct answer
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)'.

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

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

  1. External and internal intercostal muscles

  2. Diaphragm and abdominal muscles

  3. Diaphragm and external intercostal muscles

  4. Diaphragm and intercostal muscles
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

Which of the following statement is correct?

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.