Question

Figures A and B are parts of the lung showing exchange of gases during inhalation and exhalation. Study the same and answer the questions that follow.

1. Label parts 1-3 in Figure A.
2. Name the gases represented by the arrows numbered 4 and 5 in Figure B.
3. Which pigment is present on the surface of the parts labeled 6?
4. What is the function of this pigment?

Answer 1

a. Labeling of figure A is as follows:

1. Bronchiole: The bronchioles are finer tubes in the lungs which branch off from the larger bronchi and enter each lung.
2. Alveoli: Alveoli are the tiny air sacs present at the end of terminal bronchioles in the lungs where the exchange of gases takes place.
3. Capillaries: Capillaries are a network formed of small blood vessels that allows the exchange of materials from surrounding tissues.

b. The gases are :

4. Oxygen: Oxygen diffuses into the blood from the alveoli which are carried by the artery and pulmonary vein.
5. Carbon dioxide: Carbon dioxide diffuses out from the blood capillaries into the alveolus through veins and pulmonary arteries.

c. Hemoglobin: Hemoglobin is the iron-containing protein present in red blood cells (RBCs).

d. Function of haemoglobin:

1. It is a respiratory pigment that plays an important role in transporting oxygen from the lungs to different parts of the body.
2. Haemoglobin is the red pigment due to which blood appears red in colour.