Question

What is the role of epiglottis and diaphragm in respiration?

Answer 1

Hint: Respiration is the biological process of exchange of gases in which oxygen is inhaled and carbon dioxide is exhaled. In the process of respiration various parts are involved to form a respiratory system.

Complete Answer:
Respiratory system is the system in which various parts are involved with lungs as a major part for performing the process of respiration. The respiratory system includes:
- Nasal cavity
- Pharynx
- Larynx
- Trachea
- Paired lungs
Apart from these parts epiglottis and diaphragm are also held during the process of respiration.
Epiglottis: It is a leaf shaped valvular flap located behind the tongue, at the top of the larynx (or voice box). It is made up of cartilage and helps in the performing various functions like:
- It prevents the entry of food in the windpipe and closes the windpipe while it is eating, so that food is not accidentally entered in the windpipe.
- It allows the passage of air from the pharynx to the larynx.

Diaphragm: It is the muscular dome shaped structure located below the lungs and separates the thoracic cavity from the abdominal cavity. It is responsible for performing function like:
- During inhalation, the diaphragm contract which increases the volume of thoracic cavity in the antero-posterior axis that ultimately raises the ribs and sternum and the air moves inward. The diaphragm moves downward during inspiration.
- During exhalation, the diaphragm relaxes which decreases the volume of the thoracic cavity and the diaphragm returns to its normal state. Ribs and sternum returned to their original position and the air moved outward. The diaphragm moves upward during expiration.

Note: The diaphragm is also involved in various non-respiratory functions like vomiting, urination and defecation by increasing the intra-abdominal pressure. It also helps in childbirth. The birds do not have diaphragm , therefore they do not breathe in the same way as mammals do and do not rely on creating a negative pressure in the thoracic cavity , at least not to the same extent.