Sense of Smell

Prepared by:Mrs. Shirley P. Valera

Grade 3 St. Francis /St. AugustineSY 2014-2015

Nose

- Is also a part of the respiratory system.You inhale the air that carries the odor of an object through your nose.

- The nose is divided into external part and internal part

External Part

• The external part is your nose . Your nose is made up of bone and cartilage. They shape to your nose.

• Odors of object are carried by the air to your nose . When you breathe , the odors enter the two openings of your nose called nostrils. Nostrils serve as entrance to your nasal cavity.

Internal Part

• The interior part of the nose is divided into two major passages called nostrils. Each nostril has the respiratory region, which is used for breathing; and the olfactory region , which is used for smelling.

Internal Part

• The nasal cavities are lined with small, hairlike structures called cilia. These cavities also contain mucous membranes that secrete a sticky fluid called mucus. As you inhale , air that enters the nose is filtered by the cilia, moistened by the mucus , and warmed by the blood within the blood vessels.

Internal Part

• The olfactory region, which is located within the mucous membrane , contains olfactory cells. These are the nerve cells sensitive to odor. Stimulation of these cells by the odor from the environment results in the sensation of smell. The odor carried by the air stimulate the nerve cells.The messages are then carried by the nerve cells to the brain where they are interpreted.

Smelling too long

• Even if you are several meters away from the poultry farm you can already smell the bad odor of chicken manure, so you cover your nose with a handkerchief. Notice that poultry ma n does not cover his nose. He cannot smell the bad odor anymore because ha has gotten used to it. The olfactory nerve cells of his nose become less sensitive to the bad odor of the chicken manure because of long exposure to it.

Common Nose Ailments

• Nosebleed – usually caused by an injury to any part inside the nose, head injury , high blood pressure , or weak blood vessels in the nose. Infections and blood disorders can also cause nosebleed.

Proper Care for the Nose1. Cover your nose if you are in the dusty or

stinky area.2. Keep your nose clean. Use clean and soft

cloth to clean it.3. Avoid blowing your nose hard when you have

colds to prevent nose bleeding.

Proper care for the Nose

4. Avoid putting any of your fingers or any pointed object inside your nose.

5. Stay away from smoky places.

Sense of Smell of the snake A snake flick outs its tongue to pick up the tiny

particles left by animas such as mice and birds. The particles may be in the air , along the ground , or on a surface such as a tree trunk. When the snake brings its tongue back inside its mouth, the particles enter a special part in the roof of its mouth. This particles identifies the smell , and the snake can track down its food.

For