Explain in details about Respiratory system

Respiratory system starts from nostrils through which we inhale air in the nasal cavity. Then, air enters pharynx and goes through larynx to enter trachea which is also known as wind pipe. Larynx leads to trachea through a small opening known as glottis. Glottis is guarded by a leaf like structure known as epiglottis so that food particles cannot enter trachea while taking food. Larynx also functions as a voice box. It produces sound by the vibrations of its two vocal cords.

Trachea is a tubular structure having rings of soft bones, so it does not collapse. At middle of thorax, trachea divides into two right and left primary bronchus to enter right and left lungs. Two primary bronchi go on dividing into secondary, tertiary bronchi, bronchioles and terminal bronchioles. Terminal bronchiole again divides into alveolar ducts which ultimately enter air sacs known as alveoli. Terminal bronchiole, alveoli with their alveolar ducts is functional units of respiratory system.

Two lungs are covered by layers of covering known as pleura. And it contains a thin layer of fluid which prevents friction between lungs and thoracic wall. The thoracic cavity is separated from abdominal cavity by a muscular partition which is known as diaphragm. Diaphragm plays important role in respiration. Mechanical process of inspiration and expiration involves movements of diaphragm and ribs.

Respiration is an automatic act. The normal rate of respiration in adult is 14 to 18 breaths per minute. Respiration is regulated by respiratory centers present in medulla oblongata of the brain system