Biology

Respiration and Gas Exchange

989 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, the pressure of air is maximum in ___________.

  1. Trachea

  2. Bronchus

  3. Alveoli

  4. Environment
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During inspiration, the contraction of the diaphragm and intercostal muscles increases the volume of the thoracic cavity, causing the internal pressure (in alveoli and bronchi) to drop below atmospheric pressure. Consequently, air rushes in from the environment, where the pressure is now at a relative maximum compared to the lungs.

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.

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

Expiration involves

  1. Relaxation of diaphragm and intercostal muscles

  2. Contraction of diaphragm and intercostal muscles

  3. Contraction of diaphragm muscles

  4. Contraction of intercostal muscles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When the diaphragm relaxes, air is exhaled by elastic recoil of the lung and the tissues lining the thoracic cavity in conjunction with the abdominal muscles which act as an antagonist paired with the diaphragm's contraction. The internal intercostals assist in expiration by pulling the ribcage down.

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

Which one of the following statement is correct?

  1. Chest expands because air enters into the lungs.

  2. Air enters into the lungs because chest expands.

  3. The muscles of the diaphragm contracts because air enters into the lungs.

  4. All of the above statements are correct.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When we breathe in, or inhale, the diaphragm contracts (tightens) and moves downward. This increases the space in the chest cavity, into which the lungs expand. The intercostal muscles between the ribs also help enlarge the chest cavity. They contract to pull the rib cage both upward and outward when we inhale. As the lungs expand, air is sucked in through the nose or mouth. The air travels down the windpipe and into the lungs. After passing through the bronchial tubes, the air finally reaches and enters the alveoli (air sacs).

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

The tissue respiration refers to 

  1. Inspiration

  2. External respiration

  3. Internal respiration

  4. Expiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Internal respiration refers to gas exchange across the respiratory membrane in the metabolizing tissues. External respiration refers to gas exchange across the respiratory membrane in the lungs. Pulmonary ventilation is the process by which oxygen enters and carbon dioxide exits the alveoli. Respiration is the process by which oxygen and carbon dioxide diffuse in and out of the blood. 

Multiple choice innate and learned behaviour option a: neurobiology and behaviour biology

An effect of drinking is

  1. Rapid breathing

  2. Deeper breathing

  3. Slower breathing

  4. Both A and B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Drinking i.e. consuming alcohol causes deposition of alcoholic fat on the walls of blood vessels due to which lumen of blood vessels get reduced. This leads to increase in blood pressure and hence, the activity of heart is increased. The heart beat and strength of heart contraction becomes fast and the person may run short of breath. This may also lead to fatigue of muscles.
So, the correct answer is 'Rapid breathing'.
Multiple choice zoology respiratory system of human mechanism of respiration respiratory cycle breathing and exchange of gas

Which of the following sequences is correct to initiate inspiration? 
(i)    The contraction of external intercostal muscles raises the ribs and sternum
(ii)   Volume of thorax increases in the dorso-ventral axis 
(iii)  Intrapulmonary pressure decreases 
(iv)  Diaphragm contraction 
(v)   Air rushes into lungs 
(vi)   Volume of thorax increases in the anterior-posterior axis 

  1. (i),(ii),(iv),(v),(iii),(vi)

  2. (i), (ii), (iii), (iv), (vi), (v)

  3. (i),(ii),(iv),(vi),(iii),(v)

  4. (vi), (v), (i), (ii), (iii), (iv)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct sequence of events in the initiation of respiration is:
(i)    The contraction of external intercostal muscles raises the ribs and sternum
(ii)    The volume of thorax increases in the dorsoventral axis
(iv)    Diaphragm contraction
(vi)    The volume of thorax increases in the anterior-posterior axis
(iii)    Intrapulmonary pressure decreases

(v)    Air rushes into lungs
So, the correct answer is '(i),(ii),(iv),(vi),(iii),(v)'.

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

The ventilation movements of the lungs in mammals are governed by

  1. muscular walls of lung

  2. diaphragm

  3. costal muscles

  4. both (b) and (c).
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The relaxation and contraction of the diaphragm and the movement of the costal muscles present in the thorax of an individual are responsible for the ventilation movements of the lungs that facilitate respiration.
So, the correct answer is 'both (b) and (c)'.