Why do dogs always wet nose?

Many people think that a dog's wet nose is a sign of good health, but actually nasal mucus is an important screening tool in the dog's complex olfactory system.

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Experts used to think that dogs have a superior sense of smell (used to detect drugs and even cancer) through neurons and their receptors.

Dogs have more nerve cells in the trachea than humans. They also have a variety of receptor cells to receive chemicals.

A previous study demonstrated that dogs can detect bladder cancer by sniffing urine. Another study showed that if dogs smell their breath, the difference between a person with breast cancer and a lung cancer can be distinguished.

Scientists at the University of Pennsylvania used magnetic resonance imaging to understand how air moves in the dog's trachea system. They find neurons 'pick up' molecules at Different points in the trachea tube. The mucus in the dog's nose is responsible for preventing certain types of odor molecules so that they cannot penetrate inside.

Dr. Brent Craven, the lead researcher, said: 'Classifying smells before they reach receptor cells is important for dogs. The nasal mucus helps them remove unnecessary odors, so that nerve cells can focus on important smells. '