Explain why sneezing occurs and the nose runs?

Sneezing

Sneezing is a sudden, forceful expulsion of air through the nose and mouth. It is a natural reflex that helps to clear the airways of irritants, such as dust, pollen, and pet dander.

When an irritant enters the nose, it stimulates the trigeminal nerve, which sends a signal to the brain. The brain then sends a signal back to the muscles of the chest and abdomen, which contract and force air out of the lungs.

Sneezing can also be triggered by other factors, such as bright light, cold air, and spicy food.

Runny nose

A runny nose is a common symptom of allergies, colds, and the flu. It occurs when the blood vessels in the nose become engorged and leak fluid.

The fluid that comes out of a runny nose can be clear, yellow, or green. The color of the fluid can give you some clues about the cause of your runny nose.

* Clear fluid: A clear runny nose is often a sign of allergies or a cold.

* Yellow or green fluid: A yellow or green runny nose can be a sign of a bacterial infection, such as a sinus infection.

In addition to sneezing and a runny nose, other symptoms of allergies, colds, and the flu can include:

* Congestion

* Sore throat

* Cough

* Fever

* Headache

* Muscle aches

* Fatigue

If you have a runny nose that lasts for more than a week, you should see a doctor to rule out any underlying medical conditions.