Question

Cough reflex.

Hint:

The cough reflex is a key protective mechanism for clearing the airways of irritants, but chronic or ineffective coughing may indicate underlying respiratory pathology.

Answer 1

Step 1: Understanding the Cough Reflex.
The cough reflex is a protective mechanism that helps clear the airways of irritants such as dust, mucus, or foreign bodies. It is initiated by stimulation of sensory receptors in the airways, which send signals to the brain to initiate the coughing process.

Step 2: Mechanism of the Cough Reflex.
The cough reflex involves the following steps:
1. Irritant Detection: Sensory receptors (primarily in the larynx, trachea, and bronchi) detect irritants, which can include particles, smoke, or infections.
2. Signal Transmission: The irritant triggers a signal that travels via the vagus nerve to the brainstem.
3. Inspiration: The brainstem coordinates the reflex, causing deep inspiration to fill the lungs with air.
4. Compression: The glottis closes, and the respiratory muscles contract, building up pressure in the lungs.
5. Expulsion: The glottis opens suddenly, and the air is expelled forcefully from the lungs, expelling the irritant from the airways.

Step 3: Clinical Relevance.
The cough reflex is vital for airway clearance, but it can become dysfunctional in conditions like chronic cough, asthma, or neurological disorders, where the reflex may be either overactive or impaired.