Question

State the role of the following in the human respiratory system with the help of a diagram (i) Nasal cavity (ii) Diaphragm (iii) Alveoli.

Answer 1

(I) The nasal cavity is a hollow space within the nose and skull that is lined with hairs and mucus membrane.
# The function of the nasal cavity is to warm, moisturize, and filter air entering the body before it reaches the lungs.

(ii) The diaphragm separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity and performs an important function in respiration:
# as the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn into the lungs.

(iii) Alveoli are tiny sacs within our lungs that allow oxygen and carbon dioxide to move between the lungs and bloodstream. 

Answer 2

a) Nasal cavity: It warms, moisturizes, and filters air entering the body before it reaches the lungs.

b) Diaphragm: It contracts and flattens when you inhale. This creates a vacuum effect that pulls air into the lungs. When you exhale, the diaphragm relaxes and the air is pushed out of lungs.

c) Alveoli: They enable gaseous diffusion with blood capillaries