What happened when the intrapulmonary pressure is less than atmospheric pressure ?

Options

A. Inspiration
B. Expiration
C. Emphysema
D. Forceful expiration

Answer

To solve the question "What happens when the intrapulmonary pressure is less than atmospheric pressure?", we can follow these steps:

### Step 1: Understand the Concept of Intrapulmonary Pressure
Intrapulmonary pressure refers to the pressure within the lungs (alveoli). It is crucial to understand how this pressure interacts with atmospheric pressure during the process of breathing.

**Hint:** Intrapulmonary pressure is the pressure inside the lungs, and it changes during breathing.

### Step 2: Compare Intrapulmonary Pressure with Atmospheric Pressure
When intrapulmonary pressure is less than atmospheric pressure, it creates a pressure gradient. This means that the pressure inside the lungs is lower than the pressure outside the body.

**Hint:** A pressure gradient is essential for air movement; air moves from high pressure to low pressure.

### Step 3: Identify the Breathing Process
When the intrapulmonary pressure is lower than atmospheric pressure, air will flow into the lungs. This process is known as inspiration (inhalation), where atmospheric air is drawn into the lungs.

**Hint:** Inspiration occurs when the pressure inside the lungs is less than the pressure outside.

### Step 4: Eliminate Incorrect Options
The other options provided in the question are:
- B. Expiration
- C. Emphysema
- D. Forceful expiration

Since expiration occurs when intrapulmonary pressure is higher than atmospheric pressure, and emphysema is a condition affecting lung function rather than a breathing process, these options can be eliminated.

**Hint:** Expiration is the opposite of inspiration; it occurs when the pressure inside the lungs is greater than outside.

### Step 5: Conclusion
Based on the understanding that when intrapulmonary pressure is less than atmospheric pressure, the process that occurs is inspiration, we can conclude that the correct answer is:

**Answer: A. Inspiration**