Question

What is respiration? Write a detail note on human respiratory organs.

Answer 1

Respiration is the biochemical process in which the cells of an organism obtain energy by combining oxygen and glucose, resulting in the release of carbon dioxide, water, and ATP. The main organs involved in human respiration are;

Nose: Main external opening for the respiratory system and its function is to warm, moisturize, and filter air entering the body before it reaches the lungs.

Mouth: The secondary external opening for the respiratory tract and used to supplement or replace nasal cavities function when needed

Pharynx: It is also known as the throat. Divided into nasopharynx, oropharynx, and laryngopharynx. There is a flap of elastic cartilage called epiglottis, that acts as a switch between the trachea and the esophagus and prevent food from going into the lungs.

Larynx: It is also known as the voice box and it connects laryngopharynx to the trachea. It contains special structures known as vocal folds, which allow the body to produce the sounds of speech and singing. The vocal folds are folds of mucous membrane that vibrate to produce vocal sounds.

Trachea: It connects the larynx to the bronchi. The main function of the trachea is to provide a clear airway for air to enter and exit the lungs. The epithelium lining the trachea produces mucus that traps dust and other contaminants and prevents it from reaching the lungs.

Bronchi and Bronchioles: From the trachea, the airway splits into left and right branches known as primary bronchi. They run into each lung before branching into secondary bronchi. They again split into many smaller tertiary bronchi within each lobe and they split into many smaller bronchis of less than 1mm size, and are called bronchioles and they spread throughout the lungs. The cartilages in the bronchi become more widely spaced as they are being branched. The bronchioles differ from the structure of the bronchi in that they do not contain any cartilage at all. The presence of smooth muscles and elastin allow the smaller bronchi and bronchioles to be more flexible and contractile. The main function of the bronchi and bronchioles is to carry air from the trachea into the lungs. When greater volumes of air are required by the body, such as during exercise, the smooth muscle relaxes to dilate the bronchi and bronchioles.

Lungs: The lungs are a pair of large, spongy organs found near to the thoracic region and surrounded by a pleural membrane which provides space for expansion and contraction. The interior of the lungs is made up of spongy tissues containing many capillaries and around 30 million tiny sacs known as alveoli. The alveoli are cup-shaped structures found at the end of the terminal bronchioles and surrounded by capillaries. The alveoli are lined with thin simple squamous epithelium that allows air entering the alveoli to exchange its gases with the blood passing through the capillaries.