Do you know how air reaches the lungs in human body? In the previous lesson we discussed the types of respiration in human body ( click here to visit the previous lesson ). In this lesson we will discuss, what path does the air takes to reach the lungs.
How gas reaches the lungs?
The organs involved in the process of gas traveling to the lungs are the following:-
The Nose:
Air usually enters our body through the two external nostrils. The walls of the nostrils are covered with a fringe of hairs. The two nostrils lead to the the nasal passages which are line with a moist substance, known as mucous. The dust, bacteria and germs in the air are blocked by the hairs in the nostrils and the mucous in lining the nasal passages. As air passages through the nasal passages it is warmed and moistened. The air then passes into the pharynx, from it here it passes into the larynx and then into your trachea through an opening known as glottis.
Trachea:
The trachea (windpipe) is supported by C-shaped rings of cartilage. These cartilage keeps the lumen of the trachea open. The membrane next to the lumen is the epithelium.
There two types of cells in epithelium:
The gland cells which secrete mucus to trap dust particles and germs.
The ciliated cells which are hair-like, known as cilia. They are on the surfaces of the epithelium. The cilia push the dust-trapped mucus up the trachea.
Bronchi and Bronchioles:
The air then passes into the bronchi, two tubes which divide the trachea. Each bronchus carries air into the lung. Each bronchus divides repeatedly, causing rise to numerous bronchioles. These are very fine tubes, Each bronchiole ends in a cluster of air sacs or alveoli.
Alveoli:
Gas exchange takes place through the walls of these air sacs. There are numerous alveoli present in the lungs, provide a large surface area to volume ratio.
In the next lesson we will discuss how gas exchange takes place in human body.
*All pictures are taken from google*
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