Question

Select the option that best fills the missing gaps about inhalation and exhalation

$\begin{array}{ccc}& \text{Inhalation}& \text{Exhalation}\\ \text{Diaphragm}& \text{---(A)---}& \text{---(B)---}\\ \text{Intrapulmonary volume}& \text{---(C)---}& \text{Decreases}\\ \text{Intrapulmonary pressure}& \text{Decreases}& \text{---(D)---}\end{array}$

• A. (A) Contracts, (B) Relaxes, (C) Increases, (D) Increases
• B. (A) Contracts, (B) Relaxes, (C) Increases, (D) Decreases
• C. (A) Relaxes, (B) Contracts, (C) Increases, (D) Increases
• D. (A) Relaxes, (B) Contracts, (C) Decreases, (D) Increases

Answer 1

The correct option is A (A) Contracts, (B) Relaxes, (C) Increases, (D) Increases

During inhalation, the internal intercostal muscles relax and the external intercostal muscles contract, pulling the ribcage upwards and outwards. The diaphragm contracts, pulling downwards. The lung volume increases and the air pressure inside decreases and air is pushed into the lungs.

During exhalation, the external intercostal muscles relax and the internal intercostal muscles contract, pulling the ribcage downwards and inwards. The diaphragm relaxes, moving back upwards. The lung volume decreases and the air pressure inside increases and air is pushed out of the lungs.