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 regulation of breathing human respiratory system contro and disorders of respiration

What is dead space air?  

  1. Air in the alveoli

  2. Air in the lungs

  3. Air in the pharynx

  4. Air in the trachea and bronchi
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Some amount of air remains behind in the various parts of the respiratory tract.
  • The air in the trachea and bronchi (where no diffusion occurs) is called dead space air.
  • The air remaining in the alveoli or air sacs in alveolar air. The maximum volume of air that can be exchanged in one breath in and out is called the vital capacity. It is about 5000ml. 

Therefore, the correct answer is option D.

Multiple choice zoology respiratory system of human regulation of breathing human respiratory system contro and disorders of respiration

The amount of volume of air that can be inspired / expired normally is called

  1. Tidal volume

  2. Vital capacity

  3. Residual volume

  4. Normal volume
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tidal Volume (TV) is the amount of volume of air that can be inspired / expired normally.

Vital Capacity is the greatest volume of air that can be expelled from the lungs after taking the deepest possible breath.
Residual volume is the volume of air still remaining in the lungs after the most forcible expiration possible. Hence, option A is correct.

Multiple choice zoology respiratory system of human regulation of breathing human respiratory system contro and disorders of respiration

Person living at sea level has _________ lung capacity than a person living at high altitudes. 

  1. Smaller

  2. Higher

  3. Equal

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A person who is born and lives at sea level will develop a slightly smaller lung capacity than a person who spends their life at a high altitude. This is because the partial pressure of oxygen is lower at higher altitude which, as a result means that oxygen less readily diffuses into the bloodstream. In response to higher altitude, the body's diffusing capacity increases in order to process more air. 

Therefore, the correct answer is option A.

Multiple choice zoology respiratory system of human regulation of breathing human respiratory system contro and disorders of respiration

_________ is the volume of air inhaled in a single breath. 

  1. Inspiratory volume

  2. Tidal volume

  3. Residual volume

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total lung capacity of the adult male is six liters. Tidal volume is the volume of air inhaled in a single, normal breath. Inspiratory capacity is the amount of air taken in during a deep breath, while residual volume is the amount of air left in the lungs after forceful respiration.

Therefore, the correct answer is option B.

Multiple choice zoology respiratory system of human regulation of breathing human respiratory system contro and disorders of respiration

The inspiratory reserve volume is also known as 

  1. Supplemental air

  2. Inhaled air

  3. Complemental air

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During one breath in and out, the volume of gas exchanged is called the tidal volume. It is about 450ml during quiet breathing. The volume of air that can be drawn in after normal inspiration is about 1500 ml and is called as the inspiratory reserve volume (IRV) or complemental air.

Therefore, the correct answer is option C.

Multiple choice zoology breathing and respiration regulation of breathing human respiratory system contro and disorders of respiration

During heavy exercise, the breathing rate can increase upto ........... per minute.

  1. 35 times

  2. 40 times

  3. 20 times

  4. 25 times
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During exercise, your lungs and respiratory system must provide more oxygen to the blood.  You will breathe harder and faster because: Respiratory muscles are stimulated by sympathetic nerves in order to increase the rate of breathing. If the exercise is intense, breathing rates may increase from a typical resting rate of 15 breaths per minute up to 40 – 50 breaths per minute. Hence, during heavy exercise, the breathing rate can increase up to 25 times.

So, the correct option is '25 times'. 

Multiple choice zoology breathing and respiration regulation of breathing human respiratory system contro and disorders of respiration

Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort?

  1. One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.

  2. The lungs can be made fully empty by forcefully breathing out all air from them.

  3. One can breathe out air totally without oxygen.

  4. One can breathe out air through eustachian tubes by closing both the nose and the mouth.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Normally the inspired air constitutes about 20.84% of oxygen whereas the expired air constitutes about 15.7% of oxygen. And even if one holds his or her breath, it is not possible to breathe out air totally without oxygen.
  • The eustachian tube is a canal that connects the middle ear to the nasopharynx. It controls the pressure within the middle ear, making it equal to the air pressure outside the body. No one can breathe out air through eustachian tubes by closing both the nose and the mouth.
  • Yes, one can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all.
  • The lungs cannot be made fully empty by forcefully breathing out all air from them. Residual volume is always present in the lungs, even after the maximum forceful expiration effort. It is about 1500 ml of the air.
Multiple choice zoology the respiratory system regulation of breathing human respiratory system contro and disorders of respiration

Pick the correct statement.

  1. The contraction of internal intercostal muscles lifts up the ribs and sternum.

  2. The thoracic cavity is anatomically an air tight chamber.
  3. Healthy man can inspire approximately $500$ ml of air per minute.

  4. During expiration, the intrapulmonary pressure is slightly below the surrounding atmospheric pressure.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The thoracic chamber is formed dorsally by the vertebral column, ventrally by the sternum, laterally by ribs and lower side by the dome-shaped diaphragm, it is an air-tight chamber.

So, the correct option is 'The thoracic cavity is anatomically an airtight chamber.'

Multiple choice zoology the respiratory system regulation of breathing human respiratory system contro and disorders of respiration

Which one of the following statements is incorrect?

  1. The principle of countercurrent flow facilitates efficient respiration m gilis of fishes.

  2. The residual air in lungs slightly decreases the efficiency of respiration in mammals.

  3. The presence of non-respiratory air sacs, increases the efficiency of respiration in birds.

  4. In insects, circulating body fluids serve to distribute oxygen to tissues.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In insects, blood (haemolymph) does not contain an oxygen-carrying pigment. Hence it does not help in respiration. Instead, insects have spiracles and tracheae that carry $O _{2}$ to different tissues.

Multiple choice evs respiration in organism respiration in humans mechanism of respiration in animals human lungs

Hiccough (hiccup) is due to activity of

  1. Intercostal muscle

  2. Food in air tract

  3. Diaphragm

  4. Inadequate oxygen in environment
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • Hiccup is also called as a hiccough. It is an involuntary activity of the diaphragm. During hiccups, the diaphragm muscle shows several involuntary contractions. 
  • When the diaphragm muscle contracts, the opening between the vocal cords snaps shut to check the inflow of air. 
  • This results in the hic or hiccup sound. This results due to irritation of the nerves. 

Thus, the correct answer is 'Diaphragm.'

Multiple choice evs respiration in organism respiration in humans mechanism of respiration in animals human lungs respiration in human beings respiratory organs in humans

Which of the following changes occur in diaphragm and intercoastal muscles when expiration of air takes place?

  1. External intercostal muscles relax and diaphragm contracts

  2. External intercostal muscles contracts and diaphragm relaxes

  3. External intercostal muscles and diaphragm relaxes

  4. External intercostal muscles and diaphragm contracts
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice evs respiration in organism respiration in humans mechanism of respiration in animals human lungs respiration in human beings respiratory organs in humans

The respiratory centre leading to faster breathing is on account of ________________.

  1. Venous blood entering the respiratory centre

  2. Arterial blood entering respiratory

  3. Venous blood leaving the respiratory centre

  4. Arterial blood leaving the respiratory centre
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The medulla oblongata is the primary respiratory control centre. Its main function is to send signals to the muscles that control respiration to cause breathing to occur. The respiratory control centre increase respiratory rate on the account of decrease in blood pH, as the oxygenated blood through veins enter the system, decrease in $CO _2$ levels, increased respiratory rate.