The respiratory system starts with the nose where we breathe the air from and leads to the larynx, the wind pipe also called trachea, the two branches of trachea also called the bronchi and the lungs. Inside the lungs the bronchi divide further into bronchioles. The main function of the respiratory system is to make the most vital ingredient of life, namely the oxygen available to the system. Oxygen is said to be the most vital ingredient for life because it is a well known fact that a person can live without food or water for a few days but without oxygen he cannot live longer than a few moments.

The activity of life that goes on constantly inside the system is based on the biochemical processes which cannot go on without a continuous supply of energy. The oxygen inhaled during respiration is the main component for the production of energy inside the human system. The energy we need comes from the food we eat especially from the breakdown of carbohydrates, fats and proteins. The food is oxidised inside the system to yield energy. In this process carbon dioxide is released which is liberated along with water. Water and carbon dioxide are the waste products of respiration which are then removed from the system through the blood.

There are two types of respiration happening in the system all the time. These are called external respiration and internal or tissue respiration. In the process of external respiration oxygen is taken into the body from the external source of outside air. This atmospheric air is transferred to the blood and carbon dioxide is eliminated by the lungs. The internal or tissue respiration happens when the oxygen taken in by the blood is distributed to the cells and the carbon dioxide is collected from the cells. This happens by the process of exchange of gases. All the tissue cells are richly supplied with blood via small capillaries. There is mutual exchange of oxygen and carbon dioxide through the thin walls of the cells by the process of diffusion. For the exchange of gases a large amount of blood is needed by the lungs as the process of tissue respiration is dependent upon the direct exposure of blood to the oxygen.

The lungs are spongy organs which are pink in colour. They are very thin walled and their surface area becomes large when they are filled with air. The lungs are very delicate and so they are enclosed in the rib cage for protection. The bottom portion is protected with a sheath which forms the top of the abdominal cavity also. This is called the diaphragm. Each lung is covered by a serous membrane which is in the form of a sac called the pleura. The inner part of the serous membrane covers the surface of the lungs, while the outer part lines the inner surface of the corresponding part of the chest wall. The two layers are continuous with each other and the potential space between them is called the pleural cavity. The pleural cavity is filled with a lubricating fluid.

There are rings of cartilage that support the tubular form of the trachea and keep it in its place. All the respiratory passages are covered with hair known as the cilia which constantly move to and fro with the passage of air. They act as a filtration mechanism and help in trapping the dust particles and bacteria. There is mucus coating on the cilia to help them trap the dust and dirt better. These impurities are brought to the larynx and from here they are swallowed down the oesophagus or spit out of the system.

Asthma is the chronic inflammation in the lungs which causes significant fatigue and depletion in the immune system. There is a significant loss of energy felt by asthmatics as their immune system is constantly battling with one infection after the other. This situation is especially severe in small children as their immune systems are as it is weaker than the adults. The number of cases of asthma have increased manifold in the past few years. This is because of the oxidative stress that can be read in details in the section of Yoga for Lifestyle Disorders. The ailment of asthma is also genetically related. So if there are cases of asthma in the family it makes sense to prepare for prevention because cure is not only difficult but may be impossible at times.

Yoga is the discipline that can be used very effectively for prevention of chronic degenerative diseases like asthma. This is because the yogic practices have all been designed in allegiance with the natural systems of the body. They can help retard the process of progression of the disease even if a person is genetically inclined towards a certain situation. There are yogic asanas, which are known to strengthen the respiratory system and there are practices of pranayama, which are known to even cure the symptoms of asthma. Besides the practice of yoga nidra can relax and rejuvenate the entire system. The practice of meditation is known to calm the entire system and align it towards self healing and derive curative advantages to the mind and the body.