Draw a diagram of human respiratory system and label: Trachea, Bronchi and Diaphragm.

Question

(i) Draw a diagram of human respiratory system and label: Trachea, Bronchi and Diaphragm.
(ii) Give reasons for the following:
(a) Lungs always contain residual volume of air.
(b) Nostrils are lined with mucus.

Answer 1

(ii) (a) Lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the CO₂ to be released.
(b) Mucous on the nostrils traps the harmful substances and germs present in inhaled air. It thus, filtrate the inhaled air