Tag: gas exchange

Questions Related to gas exchange

Lungs made up of which structures 

  1. Branching network of Bronchi

  2. Bronchioles

  3. Alveoli

  4. All of the above


Correct Option: D
Explanation:

Lungs are the main respiratory organs of the human respiratory system. The windpipe or trachea divides into two branches called bronchi, entering into each lung. Each bronchus in the lung further divides to form many bronchioles. These bronchioles end up in a sac-like structure called the alveoli.  Hence, the lungs are made up of bronchi, bronchioles and alveoli.

Hence, the correct answer is 'All of the above'.

The lungs are protected by two membranes called ________

  1. Pleural membrane

  2. Meninges

  3. Mucous membrane

  4. None of the above


Correct Option: A
Explanation:

The lungs are protected by two membranes called the pleural membranes. The outer pleural membrane is called the pleura and the inner one is called the visceral or pulmonary layer. There is a space between the two layers called the intrapleural space. It is filled with fluid to keep the lungs protected from the shocks and injuries.

A. Pleural membranes are present around the lungs.
B. Meninges are present around the brain and spinal cord.
C. Mucous membranes are present around he visceral organs.
Hence, the correct answer is 'Pleural Membrane'.

Read the following statements (A to D)
(A) Rib is a flat bone connected vertebral column and dorsally to the sternum.
(B) First seven pairs of ribs are called true ribs.
(C) 8$^{th}$ ,9$^{th}$ and 10$^{th}$  pairs of the ribs are called vertebro sternal ribs.
(D) 10$^{th}$ and 11$^{th}$ pairs of ribs are not connected dorsally and are therefore called floating ribs.
How many statements are correct?

  1. One

  2. Two

  3. Three

  4. None


Correct Option: A
Explanation:

A. Ribs are attached to sternum with their anterior ends.

B. First seven pair of ribs are called true ribs because their anterior are directly attached to the sternum.
C. The 8th, 9th and 10th pair of ribs are called false ribs.
D. 11tth and 12th pair of ribs are called floating ribs because their anterior ends are not attached to the sternum.
Hence only statement B is correct.
So, the correct answer is 'One'.

What do the trachea and bronchi possess in their wall  of the respiratory tract in man?

  1. C-shaped cartilagenous rings

  2. C-shaped bony rings

  3. V-shaped bony rings

  4. V-shaped cartilagenous rings


Correct Option: A
Explanation:

The trachea, primary, secondary and tertiary bronchi, and initial bronchioles are supported by incomplete cartilaginous rings. 


So, the correct answer is 'C-shaped cartilaginous rings'

The mucus produced by the goblet cells 
(I) Moistens the incoming air
(II) Traps the finest dust particles
(III) Filter out largest dust particles
(IV) Warm the incoming air

  1. I and II

  2. II and III

  3. Only IV

  4. All of these


Correct Option: B
Explanation:

A column-shaped cell found in the respiratory and intestinal tracts, which secretes the main component of mucus. The mucus produced by the goblet cells traps the finest dust particles and filter out largest dust particles.

So, the correct option is 'II and III'.

The alveoli contain specialized cells that secrete a phospholipoprotein complex known as pulmonary surfactant. The function of pulmonary surfactant is ________________________.

  1. to provide some rigidity to the alveoli to prevent lung collapse

  2. to decrease the surface tension of the alveoli, making it easier to expand them

  3. to facilitate the diffusion of $O _2$ and $CO _2$ by providing protein channels through which these gases flow

  4. to provide a sticky surface upon which dust and microbes are trapped and disposed of


Correct Option: B
Explanation:

Alveoli is the region in the lungs where exchange of gases takes place.According to histology of alveolar wall ,it contain 2types of cell

 I.e. 1-Type-1 cell 
            2.Type -2 cell which secret  DPPP(DIPAMITOYL PHOSPHATIDOYL CHOLINE OR LECITHINE) which acts as a surfactant and help in preventing collapsing of lungs.

When there is no air in initial bronchioles, they do not collapse. It is due to the presence of _________________.

  1. Lecithin

  2. Complete cartilaginous rings

  3. Incomplete cartilaginous rings

  4. Transformed elastic cartilage


Correct Option: D
Explanation:

This is due to the presence of transformed elastic cartilage which gives support to the initial bronchioles and prevents it from collapsing. The incomplete cartilaginous rings that are present in the trachea and bronchi are absent in the bronchioles. They are supported by the transformed elastic cartilage.

So, the correct option is 'transformed elastic cartilage'.

Trachea is supported by?

  1. Bone

  2. Cartilage

  3. Cardiac muscles

  4. None of these


Correct Option: A

The capacity of lungs for air in a healthy man is 

  1. 500 ml

  2. 1000 ml

  3. 1500 ml

  4. 3000 ml

  5. 6000 ml


Correct Option: E
Explanation:

Total lung capacity (TLC) is the maximum amount of air the lungs can hold when they are fully inflated. The average total lung capacity of an adult human male is about 6 litres of air. It can be calculated by using the formula TLC = TV + IRV + ERV + RV where TV is tidal volume(500 ml), IRV is inspiratory reserve volume(3100 ml), ERV is expiratory reserve volume (1200 ml) and RV (1200  ml) stands for residual volume.

So, the correct answer is option E.

The alveoli in human lung are 

  1. 3 crore

  2. 300 million 

  3. 350,000

  4. 5 lakhs


Correct Option: B
Explanation:

Alveoli are the site of respiration inside the lungs. The human lungs have 300 million alveoli with a total area of about ${100 m^2}$ which is 50 times than that of the skin surface.

So, the correct answer is option B.