Exhalation is the process of expulsion of air through the respiratory tract. Which figure illustrates the process of exhalation ?

Options

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Answer

To determine which figure illustrates the process of exhalation, we need to understand the physiological changes that occur during this process. Here’s a step-by-step breakdown:

### Step 1: Understand the Process of Exhalation
Exhalation, or expiration, is the process of expelling air from the lungs. It involves specific muscular actions and changes in the thoracic cavity.

### Step 2: Identify the Muscles Involved
During exhalation, the internal intercostal muscles contract while the diaphragm relaxes. This contraction and relaxation are crucial for the movement of air.

### Step 3: Observe the Movement of the Ribs
As the internal intercostal muscles contract, the ribs move downward and inward. This movement reduces the volume of the thoracic cavity.

### Step 4: Note the Change in the Diaphragm
The diaphragm, which is a dome-shaped muscle, becomes convex during exhalation. This change also contributes to the decrease in thoracic cavity volume.

### Step 5: Understand the Pressure Changes
With the decrease in volume of the thoracic cavity, the pressure inside the thoracic cavity increases compared to atmospheric pressure. This pressure difference is what drives air out of the lungs.

### Step 6: Analyze the Figures
Look for a figure that shows:
- The internal intercostal muscles contracting.
- The diaphragm in a dome shape.
- The ribs moving downward and inward.

### Conclusion
The correct figure illustrating the process of exhalation will depict these changes accurately, showing the movement of air out of the lungs.

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