Respiratory System of Human Body in Urdu


The respiratory system of the human body is a tract or organs which are essential for breathing. These organs collect the oxygen from outside and expel the carbon dioxide in air. Lungs are the main organs that are responsible for the respiratory process. They deliver blood enriched with oxygen to the body which is essential for the sustaining of body and they also carry the exhalation process by carrying the waste or carbon dioxide from the blood and breathe out carbon dioxide in air. Apart from this our respiratory system also filters and warms the air we are going to breathe. If the respiratory system stops working, it can cause death in 2 to 5 minutes.

Parts of Respiratory System

The respiratory system of human body is divided mainly into two parts.

  1. Upper Respiratory Tract
  2. Lower Respiratory Tract

Upper Respiratory Tract

The upper respiratory tract consists of organs above the chest. This tract consists of nasal cavity, sinuses, pharynx, and larynx.

Nose and Nasal Cavity

The air is filtered by the hairs present in the nose. They stop the large dust particles present in the air. Thetiny hairs called cilia keep the breathing air clean, but they cannot stop extra harmful air like smoke or any other poisonous air. The mucus present in the nose also helps to keep the air clean and maintain the moist in the nose. The harmful particles of air that reach inside the lungs are also expelled out by the help of mucus. Cilia also expel the dust particle by sneezing or coughing.


Sinuses are present in variable sizes and different amount of pairs. They are developed after birth and keep developing until the age of 20 approximately. Sinuses are responsible for two main functions. One is to maintain the skull lighter as they are air-filled spaces. Second as a resonance hall for voice.


The main function of the pharynx is to deliver the food and air to their proper destinations. They are also responsible for human speech. The paharynx is further divided into three parts according to its anatomy. The upper part is responsible for the delivery of air and secretion of nasal cavity to the oral pharynx.

The middle part is called oral pharynx and it covers the rear part of the oral cavity.

The lower part of the pharynx is present in the rear of tongue. It is the crossway of the air and food path. Food from here is passed to esophagus while air is passed to larynx.


The larynx is the air passageway to the lungs asanatomy. They are responsible for human speech. Sound is produced in these parts by pressurizing air through a narrow slot with the help of vocal cords.

Lower Respiratory Tract 

The lower respiratory tract is present inside the chest. It consists oftrachea, lungs, bronchi, and diaphragm.


The trachea is the main passage to the lungs and is present right between the larynx. It is a tube of about12 cm length and 2 cm width approximately. The inner part of trachea is formed by respiratory epithelium and it also contains mucous glands.


At the posterior part of the trachea, it is divided into two canals in y shape. One canal is directed in an each lung. It creates the passage for air supply to lungs.


The lungs are the largest organs of the human body. The lungs are different in size. The right one occupies 56 percent of the lung’s total area while the left one occupies the remaining 44 percent. The function of lungs is to deliver the oxygen to the capillaries of blood and also to release carbon dioxide and other air waste.


The diaphragm is an organ that is responsible for the expansion and contraction of muscles due to which air is inhaled and expelled out of the lungs.

Main Functions of the Respiratory System


The first and main function of the respiratory system is breathing. When the lungs are expanded air is inhaled and passed from oral cavities pharynx, larynx, trachea, and bronchi to lungs and when the lungs are contracted air is exhaled from the same passage. The lungs then are responsible to carry the oxygen from this air and supply it to capillaries of human body. When the red blood cells in the blood-stream carrying oxygen pass through narrow capillary tubes, they deliver oxygen to the tissues and the tissues diffuse or disperse the carbon dioxide. These red blood cells then carry carbon dioxide back to the lungs where it is diffused from them and then evolved out from the human body.

Human Speech

The upper respiratory tract is also responsible for human speech. The larynx pushes the vocal cords when we speak. When the vocals cords have pushed the air passing between them causes them to vibrate, that process creates sound. Higher vibration creates high pitch sound and vice versa.


When the air enters the nasal cavity, some enzymes signal the brain. The neurons of the brain get the signal and interpret the smell from the air.


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