NCERT Class 11-Biology: Chapter –17 Breathing and Exchange of Gases Part 3

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Question 2:

A fluid filled double membranous layer surrounds the lungs. Name it and mention its important function.

Answer:

A fluid filled double membranous layer surrounds the lungs is called Pleura.

Functions of pleura:

1. The space between the pleura also known as pleural cavity consists of a fluid called pleural fluid. This fluid lubricates and helps the two pleural tissue to slide easily against each other during respiratory movements.

Question 3:

Name the primary site of exchange of gases in our body?

Answer:

1. The primary site of exchange of gases in our body is Alveoli. Alveoli are small balloon like structures having thin walls and have numerous thin capillaries in contact with them.

2. Inhaled oxygen from the air reaches the alveoli and diffuses into the capillaries due to difference in the pressure gradient

3. Carbon dioxide from the blood diffuses into the alveoli similarly and is exhaled.

Question 4:

Cigarette smoking causes emphysema. Give reason.

Answer:

Emphysema is a disorder in which the alveoli wall gets damaged. Excessive cigarette smoking leads to Emphysema due to the presence of various harmful chemicals like nicotine, tar, sulphur etc. Which causes damage to the alveoli wall and also decreases elasticity of the bronchioles and alveoli.

Question 5:

What is the amount of supplied to tissues through every . of oxygenated blood under normal physiological conditions?

Answer:

The amount of supplied to tissues through every . of oxygenated blood under normal physiological conditions is around 5ml.

Question 6:

A major percentage is transported by RBCs in the blood. How does the remaining percentage transported?

Answer:

A major percentage is transported by RBCs in the blood and the remaining percentage transported through plasma.

Question 7:

Arrange the following terms based on their volumes in an ascending order

a. Tidal Volume (TV)

b. Residual Volume (RV)

c. Inspiratory Reserve Volume (IRV)

d. Expiratory Capacity (EC)

Answer:

Question 8:

Complete the missing terms

a. Inspiratory Capacity ___________

b. _____

c. Functional Residual Capacity _______

Answer:

(a) TV

(b) Expiratory Capacity (EC)

(c) RV

Question 9:

Name the organs of respiration in the following organisms:

a. Flatworm - _________________________________________

b. Birds - _____________________________________________

c. Frog- ______________________________________________

d. Cockroach - ________________________________________

Answer:

(a) Body surface

(b) Lungs

(c) Lungs and skin

(d) Trachea

Question 10:

Name the important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration.

Answer:

Diaphragm and intercostal muscles

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