What is the pathway taken by air in the respiratory system ? Illustrate with a labelled diagram.
- Air enters the body through the nostrils.
- Air is filtered in the nasal cavity and its temperature is also brought close to that
of the body.
2. Pharynx: Pharynx is the junction of respiratory and digestive system. Epiglottis - a flap-like muscular valve controls movement of air and food towards their respec¬tive passages.
3. Larynx: Larynx is also called sound box. It contains vocal cords. When air passes out of the lungs and over the vocal cords, it causes them to vibrate. This produces sounds on the basis of our speech, song, etc.
4. Trachea : Trachea is also called wind pipe. It channels air to lungs.
5. Bronchi: ’
- Trachea at its lower end divides into two bronchi one leading to each lung.
- The bronchi further divided into smaller and smaller branches called bronchioles.
- Bronchioles finally terminate in clusters of air sacs called alveoli in the lungs which are very small and numerous.
- Gaseous exchange takes place here as blood capillaries take up oxygen and expel carbon dioxide here.