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

In mammals, the process of ventilation is normally controlled by the autonomic nervous system. Which among the following statements does not characterizes ventilation in humans?

  1. Afferent neurons from the carotid bodies and aortic bodies are via the glossopharyngeal nerve.

  2. During moderate exercise, ventilation increases in proportion to metabolic production of carbon dioxide.

  3. Ventilatory rate is usually controlled and determined by blood levels of oxygen as determined by metabolic rate.

  4. The tone of respiratory muscle is modulated by muscle spindles via a reflex arc.

  5. Pregnancy tends to increase ventilation.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ventilatory rate (minute volume) is strictly controlled and determined primarily by blood levels of carbon dioxide as determined by metabolic rate. Blood levels of oxygen become important in hypoxia. These levels are sensed by chemoreceptors in the medulla oblongata for pH, and the carotid and aortic bodies for oxygen and carbon dioxide.

Multiple choice

Which among the following structures is responsible for warming or cooling of inhaled air within 1 degree of body temperature?

  1. The nasal cavity

  2. The nasopharynx

  3. The larynx

  4. The oropharynx

  5. The laryngopharynx
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The nasal cavity conditions the air to be received by the other areas of the respiratory tract. Owing to the large surface area provided by the nasal conchae, the air passing through the nasal cavity is warmed or cooled to within 1 degree of body temperature.

Multiple choice

Which among the following statements regarding the human lungs is incorrect?

  1. The right lung has a higher volume, total capacity and weight than that of the left lung.

  2. The lower, oblique fissure separates the inferior from the middle and superior lobes.

  3. The upper horizontal fissure separates the superior from the middle lobe.

  4. The inferior lobe is the smallest lobe of the right lung.

  5. The development of the human lungs arises from the laryngotracheal groove.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The middle lobe is the smallest lobe of the right lung. It is wedge-shaped and includes the part of the anterior border and the anterior part of the base of the lung.

Multiple choice

The lung capacity is defined as the maximum air which can be held in the two lungs at any given time. Which among the following has minimum value?

  1. Vital capacity

  2. Expiratory reserve volume

  3. Inspiratory reserve volume

  4. Residual air

  5. Alveolar air
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Some amount of air remains in the various parts of the respiratory tract. The air in the trachea and bronchi (where no diffusion occurs) is called dead space air (350ml). The air remaining in the alveoli or air sacs is alveolar air (150ml).

Multiple choice

Which among the following can be excluded from the events taking place during the process of inspiration?

  1. Inspiration is initiated by contraction of the diaphragm.

  2. During normal quiet breathing, the phrenic nerves stimulate the diaphragm to contract.

  3. As long as pressure within the alveoli is higher than atmospheric pressure, air will continue to move inwardly.

  4. As the diaphragm contracts, the volume of the thoracic cavity increases.

  5. The lungs are held to the thoracic wall by negative pressure in the pleural cavity.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As long as pressure within the alveoli is lower than atmospheric pressure, air will continue to move inwardly. But as soon as the pressure is stabilized, air movement stops.

Multiple choice

During inhalation, the diaphragm becomes

  1. flattened

  2. oblique

  3. dome shaped

  4. remains normal
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During inhalation, the diaphragm becomes flattened to increase the surface area of the lungs so that more air can enter inside them. So, option 1 is correct.

Multiple choice

The air passing through the nostrils in humans is filtered by

  1. the mucus and innermost surface of nostrils

  2. the mucus and fine hairs in the nostrils

  3. fine hairs, mucus and innermost surface of nostrils

  4. fine hairs and innermost surface of nostrils
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The air passing through the nostrils is filtered by the fine hairs and mucus present in the nostrils. So, option 2 is correct.

Multiple choice

Which of the following statements are false? P. Breathing and respiration are synonymous. Q. Breathing is a biochemical process. R. No energy is released during breathing. S. Breathing is an extracellular process. Select the correct answer using codes given below:

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Breathing and respiration are not synonymous. Breathing is first step of respiration which refers to the intake of fresh air inside and removal of foul air outside the respiratory organs. Respiration is a biochemical process by which organic compounds in food are oxidized to carbon dioxide, water and energy in a stepwise process. Breathing is physical process.

Multiple choice

Which of the following matches of disorders of respiratory systems and their causes is not correct?

  1. Hypoxia : Oxygen shortage at tissue level

  2. Asphyxia : Increase in CO2 concentration in tissues

  3. Emphysema : viral infection

  4. Pneumonia : Bacterial infection

  5. Asthma : Hypersensitivity of the bronchioles to the foreign substances present in air that passes them
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Emphysema is due to the inflation or abnormal distension of the bronchioles or alveolar sacs resulting in loss of their elasticity.

Multiple choice

Which of the following is the unit of respiration rate?

  1. Number of breaths per day

  2. Number of breaths per second

  3. Number of breaths per hour

  4. Number of breaths per minute
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Respiration rate is number of breaths per minute. Normal breathing rate for humans is 12-20 breaths per minute.