Tag: respiration and associated structures

Questions Related to respiration and associated structures

Choose the correct answer from the alternatives given.
What are the tiny clusters of chambers for diffusion of gases in lungs?

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. Pleura

  2. Alveolar sacs

  3. Bronchioles

  4. Lobes

Show answer
Correct Option: B
Explanation:

The pleura are membranes that secrete a lubricating fluid, which allows free movement of the lungs against the chest wall while breathing. The alveolar sacs are sacs of many alveoli (clusters of chambers), that help exchange oxygen and carbon dioxide in the lungs. The bronchioles are the passageways by which air passes through the nose or mouth to the alveoli (air sacs) of the lungs. Each lobe of the lung has the same physiologic function, bringing oxygen into the bloodstream and removing carbon dioxide. So, the correct option is 'alveolar sacs'.

What is the approximate normal composition of alveolar air? 

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. 14% oxygen, 6% carbon dioxide, 80% nitrogen

  2. 21 % oxygen, 2% carbon dioxide, 77% nitrogen

  3. 16% oxygen, 3% carbon dioxide, 81 % nitrogen

  4. 10% oxygen, 8% carbon dioxide, 82% nitrogen

Show answer
Correct Option: A
Explanation:

The air present inside the alveoli or the alveolar air usually has a higher amount of oxygen than carbon dioxide. The approximate composition of alveolar air under normal condition is 14% oxygen, 6% carbon dioxide, and 80% nitrogen.

So, the correct answer is '14% oxygen, 6% carbon dioxide, 80% nitrogen'.


Membrane separating air in pulmonary alveoli from blood capillaries.

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. Alveolar epithelium

  2. Cardiac epithelium

  3. Endothelium of blood capillaries

  4. Both $'1'$ and $'3'$

Show answer
Correct Option: A
Explanation:
Here option (D) is the correct answer as-
Outermost Layer Of pulmonary alveolitis alveolar epithelium while that of blood capillaries is endothelium. Thus, both alveolar epithelium and endothelium of blood capillaries separate air in pulmonary alveoli from blood capillaries.

Rate and depth of

respiration shall increase when






zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. Oxygen concentration increases

  2. $CO _2$ concentration increases

  3. $HCO _3$ concentration increases

  4. $HCO _3$ concentration decreases

Show answer
Correct Option: B
Explanation:

(b) Activity of respiratory centres is directly proportional to the level of free $CO _2$ in blood.

State whether the following statements are true or false.
A normal man respires 70-80 times in a minute.

zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

A normal man, when resting, usually respires about 12-18 times per minute. So, the correct option is 'False'.

 A person breathing normally at rest, takes in and expels approximately half a litre of air during each respiratory cycle. This is called

zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. inspiratory reserve volume

  2. tidal volume

  3. expiratory reserve volume

  4. vital capacity.

Show answer
Correct Option: B
Explanation:

The volume of air inspired or expired during normal breath is called tidal volume. It is about 500 mL of air in average young adult man.

Heavy laboured and rapid breathing will result in which of the following?

zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. High ${CO _2}$ in blood

  2. High ${O _2}$ in atmosphere

  3. Low ${CO _2}$ in blood

  4. Low ${O _2}$ in blood

Show answer
Correct Option: C
Explanation:

Heavy laboured breathing is a sign of abnormal respiration and an increased effort to breathe. Rapid breathing or Tachypnea has seen the breathing rate in adult humans is greater than the normal 20 breaths per minute. This  breathing pattern reduces carbon dioxide in the blood due to increased rate or depth of respiration.

Which two of the following changes (a-d) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)?
(1)Increase in red blood cell size.
(2)Increase in red blood cell production.
(3)Increased breathing rate.
(4)Increase in thrombocyte count.

zoology respiration in organisms respiration in human beings respiration and associated structures respiration in humans

  1. 1 and 2

  2. 2 and 3

  3. 3 and 4

  4. 1 and 4

Show answer
Correct Option: B
Explanation:

The most significant limiting factor in high mountain regions is the lower air pressure, which makes it more difficult for oxygen to enter our vascular systems resulting into hypoxia. When we travel to high mountain areas, our bodies initially develop inefficient physiological responses. Then there is an increase in breathing and heart rate to as much as double, even while resting. Pulse rate and blood pressure go up sharply as our hearts pump harder to get more oxygen to the cells. These are stressful changes, especially for people with weak heart. Later, a more efficient response normally develops as acclimatization takes place. Additional red blood cells and capillaries are produced to carry more oxygen. The lungs increase in size to facilitate the osmosis of oxygen and carbon dioxide. There is also an increase in the vascular network of muscles which enhances the transfer of gases.

Respiratory rate in new born baby is

zoology respiration in organisms respiration in human beings respiration and associated structures respiration in humans

  1. Equal to an adult

  2. Less than an adult

  3. More than an adult

  4. None of the above

Show answer
Correct Option: C
Explanation:

Babies and children normally breathe faster than older children and adults. Newborn to 6 months: 30-60 breaths/min

6 to 12 months: 24-30 breaths/min
1 to 5 years: 20-30 breaths/min
6 to 12 years: 12-20 breaths/min

Respiratory system is derived from

zoology respiration in organisms respiration in human beings respiration and associated structures respiration in humans

  1. Ectoderm

  2. Endoderm

  3. Both A and B

  4. Endoderm and mesoderm

Show answer
Correct Option: D
Explanation:
  • The respiratory system represents the organs that are involved in the exchange of oxygen and carbon dioxide between the organism and the environment.
  • In animals, a primary layer of cells is formed during embryogenesis, three in number and are differentiated as ectoderm, mesoderm, and endoderm. The tissues produced by these layers give rise to the organs of the body. 
  • The respiratory tract with tracheae, bronchi, alveoli of the lungs is developed from the endoderm. The mesoderm forms the mesothelium from which lines the thoracic cavity and external intercostal muscles.
    Hence, the correct answer is D.