Respiratory System

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4 the Respiratory System

What is Respiratory System?

4.1     Out of different gases in the air only oxygen is important to life and the body. If the brain cells do not get enough oxygen even for a few minutes, they begin to die and the brain gets damaged and the heart stops beating. We live only when we take sufficient oxygen. Every breath we take provides essential oxygen to our body cells which produce the waste product carbon dioxide. The respiratory system includes the cone-shaped 13 cm long tube pharynx (throat), the larynx (voice box), the 13 cm long and about 2.5 cm dia tube trachea (windpipe) and the lungs.

 Oral and Nasal Cavities

4.2     Normally, the air enters the body through the nostrils. Tiny hairs in the nose help filter out dust and dirt and thus protect us from many breathing problems. But when the nose is blocked, we can breathe through the oral cavity (mouth), which though is less healthier than through the nose. There are also very tiny hairs in the windpipe, which move like grass in the wind. These tiny hairs help in carrying the trapped debris in the mucus back to the throat, which can be discarded by coughing or swallowing. The cells in the nasal cavity warm and moisten the air before it enters the lungs. The cells lining the nasal cavity and the windpipe secrete a sticky liquid called mucus, which traps any dust, dirt, bacteria and viruses breathed in.

 The Epiglottis

4.3     Both nasal and oral cavities meet at the throat. The air from the nose or mouth passes through the throat to the voice box where the vocal chords are located. The voice box is attached to the windpipe as well as the food pipe. When a person swallows, the epiglottis (a special protective flap) closes the opening to the windpipe preventing foods or liquids from entering the lungs. But if by chance food enters the windpipe, it can be brought back to the throat by coughing and then swallowing properly.