It has generally been observed that we can remain alive for some time without food, for a lesser time without water, but for a very short time without air. The process of inhalation and exhalation continuous unabated from our birth to death. Not many of us are familiar with this important function. This is the basis of our life. The following are the chief organs of our Respiratory System.

  1. Nose
  2. Pharynx
  3. Larynx
  4. Trachea (Note: These four extend up to the lungs)
  5. Bronchial Tubes
  6. Lungs
    1. Bronchioles
    2. Alveolar Tubes (in the Lungs)



  • Nose: There is the small growth of hair inside our nose and the same is intended to prevent the dust-laden air to pass through and get it well filtered before it is inhaled. When the air touches the membrane inside the nose, it first becomes warm and then goes inside. It thus saves the lungs from getting cold suddenly.


  • Pharynx: This is the passage for air through nose or mouth behind the tonsils.
  • Larynx: This is a sound producing organ. It is like a small box. Air passes out through this very organ.
  • Trachea : It is that pipe passing through which the air of the nose reaches the lungs. The upper part of the trachea in the throat somewhat bulging and wide is called larynx. The lower part of it is trachea which is 12cm. long. The chewed food morsel goes into the alimentary canal which is located a little above it & it is covered by a lid over it, fixed in the upper part of trachea. Beyond it, it branches into two parts.
  • Bronchial Tubes: The windpipe extends to a point in the upper part of the chest cavity and thereafter gets bifurcated into two parts. It is known as bronchi. One part goes into the right lung and the other to the left. Thereafter they branch out small twigs and assume the shape of a topsy-turvy tree.
  • Lungs : They are two in number. Each of the two lungs is located on either side of the chest bone in the chest cavity. In between the two, the Heart is located on the left side. The upper part of each lung is somewhat narrow and the lower part somewhat broad. The lower part of the lungs rests on the diaphragm. The lungs have innumerable air sacks. They are spread like the bunches of grapes, which expand and contract like the sponge. Each lung is enveloped by a double membrane like lining called Pleura. In between these layers is a fluid substance that protects the lungs from any hurt, shock or abrasion.



There are pure (Oxygenated) blood vessels and minute veins intended to provide proper nutrition to lungs & maintain their link with the brain. While inhaling the lungs expand in different directions-left, right, upwards and downwards. The right lung is divided into three lobes and the left into two lobes.


The process of breathing can be divided into two part :

  1. Outer-Breath: Mixing of blood with oxygen flowing out of lungs and air-chambers as well as the outflow of carbon-dioxide from the air chambers.
  2. Inner Breath: Oxygen provided by the blood cells & absorption of the same by the body and excretion of carbon-dioxide from inside.

Consequently, chemical reactions take place inside the cells in the form of oxygenation.

Through the medium of above-mentioned processes Pran (Vital energy) goes on entering into our body and it is that energy that makes our movements and actions possible. Pran is different from air & subtler then air. Just as machines are run by the power generated by electricity, similarly the creation and activity of the body remain intact by the force known as Pran.

It is by ‘Yog’ that we can keep this vital energy under control. Through its control starts with Yogasans it is really through Pranayam that we can gain complete mastery Over it.


Circulatory System’s entire function of blood circulation is based upon the respiratory system. The main organs of the Circulatory System are :

  1. Heart
  2. Lungs
  3. Archon Aorta
  4. Arteries
  5. Veins
  6. Capillaries

Our heart is located on the left side in the middle of lungs. It pumps blood into the body through the blood tubules. This process goes on continuously from birth to death. Such a marvelous pump that remains active for at least a hundred years, can hardly be found anywhere in the world. There are three kinds of capillaries (blood carriers)  in our body :

  1. Arteries: They carry pure blood from the heart to the body. The pressure exerted by the contraction of the heart (when it beats) continuous to remain in the arteries.
  2. Veins: They carry impure blood from the body to the heart.
  3. Capillaries: They are extremely subtle in nature. Passing deep into the tissues they are connected with the cells of the body. It is the job of the capillaries to bring with them. Oxygen, nutritive elements, and hormones etc. through the medium of the blood and again to mix with blood such excretory substances as carbon dioxide produced by these cells.

As regards the veins they supply blood to the Auricle located at the right chamber of the heart through the medium of super veins. The oxygenated pure blood reaches the upper chamber, Auricle located in the left side of the heart through the medium of veins in the lungs. Impure blood enters into the right ventricle by opening the one-sided valve of the right chamber and thereafter it reaches the lungs in order to get oxygenated by the arteries of the lungs. At the same time, oxygenated blood pushed into the left ventricle from the left chamber and therefrom into the outer artery.

From the aorta, the pureblood passes through small & big arteries and finally reaches the entire body through the medium of very subtle cells.

Red blood granules that carry oxygen enter micro-capillaries one by one in a line. They supply oxygen to the cells and receive carbon dioxide from them.

Thus there are two main processes of blood circulation :

(1) All round blood circulation i.e. blood circulation taking place in the entire body and

(2) Blood circulation in the lungs: i.e. blood circulation from lungs to the heart & from the heart to the lungs.

Prior to each heart-beat, both the chambers contract and thereafter both the ventricles also contract. As a result, the blood starts flowing out & both the chambers get relaxed. This way they receive the blood from both sides & it is thus that the purification and distribution of blood fake place in our body through the medium of the heart.

For the proper functioning of the heart, it is necessary that it receives a sufficient quantity of blood. As a matter of fact, the heart needs ten times the quantity of blood required by other organs. Ordinarily, the body cells also get their nourishment through the medium of blood that reaches them. It should also be noted that the heart does not get any nourishment from the blood that gathers in large quantity in its chambers and ventricles. There is a special arrangement for the nourishment of the heart. The two coronaries of the heart, branching out of the Aorta pass by its left and right side and rising upwards spread around it in branches and sub-branches. These arteries nourish the entire heart through the medium of blood. If by any reason these arteries are blocked either partially or fully the heart will not receive sufficient quantity of nourishment.

Special Note

Between two beats, the heart takes rest. Yog, therefore, teaches us the technique to increase the duration of rest. Simultaneously by the control of breath and the capacity to make if deeper and deeper, the circulation of blood becomes normal in all parts of the body. Deep breathing is done mainly in three parts of the body.

Breathing up to the upper part of the lungs: With this type of breathing nourishment of blood takes place in our neck, head and hands. Due to the lack of air in this part, the cells of the brain become weak. As a result, deafness, weakness of the eye-sight, headache, tension and such like ailments take place.

In this way, deep breathing can be done only by the person, who practices Yogasans and Panayam every day without fail. This is the real secret of a person who enjoys a sound health and a disease-free life.

In the end, we would like to mention an important point. It is that the expansion and contraction of the heart are caused by Pran, the vital energy in man. Here again, it is possible to control it with the practice of Pranayam only. This vital organ, namely the Heart can be kept healthy by the different practices of Yoga.


There are certain organs of the body that produce Rasa (Juices). They are known as Glands. They can be divided into two parts according to their demands.

  1. Duct Glands: They produce such secretions as are helpful in the healthy formation of our body. i.e. saliva, bile and pancreatic juice etc.
  2. Endocrine / Ductless Glands: No nerve emerges out of these glands. Blood reaches these glands through the blood vessels in great quantity. The chemical secretions produced by them, pass directly through the walls of the blood cells inside the glands & then mix with the blood. It s through the blood they reach the other parts of the body. Then secretions are called Hormones. These Hormones are vital to the sustenance of the human body.

The glands are located very close to five plexuses in our spinal cord.

  1. Near the Agya Plexus Pineal & Pituitary Glands.
  2. Near the Vishudhi Chakra – Thyroid and Parathyroid Glands.
  3. Near Anahat Chakra – Thymus Gland
  4. Near Manipur Chakra – Adrenal, Pancreas, Liver, Spleen and Kidney
  5. Near Swadhishthan Chakra – Testicles and Ovary.


  • Pinel Gland: It is located in a small cave-like hole a little hole a little above the hind part of the pituitary gland in the middle of the brain.
  • It is instrumental in the growth of the body and controls the sex-glands.
  • It is related to the self-regulated nervous system of the body.
  • The secretion of this gland controls other glands.
  • It normalizes the effect of light on the color of the skin and balances the cells of the brain. It is also helpful in the prevention of general deformities.

Important Note

The following methods are very effective in activating this gland (1) Meditation (2) The first and twelfth posture of Surya Namaskar (3) Shashank asan and (4) Shirsh asan


  • Pituitary Gland: This gland is located at the base of the brain inside the skull and is connected with the hypothalamus. This gland functions with the help of other glands. This gland becomes active when other glands stop functioning. When the secretion of the glands of other hormones increases this gland reduces its secretion.
  • Decrease and increase in height depends on the secretion of this gland as it affects both our bones and muscles.
  • This gland activates the seminal cells in men and ovary in females.
  • Breasts of a mother get filled milk after the delivery of a child due to this very gland.
  • This gland influences the vessels in the kidneys and stimulates them to absorb more liquid. It reduces urination.

Note: One should practice meditation and asanas to stimulate this gland.

    • Thyroid Gland: This gland is located at the upper end of the bronchial tube near the vocal cord. This gland is heavier in women than in men. It grasps the fundamental substance called iodine.
    • This gland keeps our youth intact.
    • It utilizes iodine in the secretion of those hormones which are helpful in the metabolism of fats, proteins, and carbohydrates. Thus it helps in the process of digestion.
  • It is especially helpful in the production and distribution of electric energy in the brain.
  • The secretion of this gland helps in building up nerves and brain tissues.
  • It keeps up the equilibrium of the brain or intellectual harmony is sustained by this very gland.

Special Note

The fifth and eighth pose of Surya Namaskar, Bhujangasan, Sarvangasana and Matsyasan (First pose) are very effective in activating this gland.


  • Parathyroid Glands: These glands are located above and below the thyroid gland near the vocal cord. It is sheltered by the left and right portions of the thyroid gland. Both in their function and formation, they are entirely different from the thyroid gland. These glands control the quantum of calcium in the blood and play an important role in activating our muscles & nervous system.


Irregular secretion from these glands results in many diseases, such as the decay in bones, frailibility etc.


  • Thymus Gland: This gland is nestled behind the meeting point of collarbone and neck in the middle of the chest a little above the heart. It has got two chunks. It takes care of the body development of our babies and protects them from the disease. This gland does not allow the sex glands to grow up to this age.


It is instrumental in the proper development of the brain.

It also helps in the formation of our lymph cells.

It is instrumental in the process of the excretion of foreign matter from our body.

Special Note

This gland is activated by the sixth pose of Surya Namaskar Shalabhasan, Ushtrasan, and Ujai Pranayam.

  • Adrenal Gland: Two triangular glands above the kidneys and attached to the diaphragm are called Adrenal Gland. Like other glands, this gland discharges maximum quantum of secretion. The secretion of this gland is most essential for the protection of our life. Its cortisone-like hormones cures more than one hundred diseases like gout, defects of blood circulation, defects of the colon (large intestine), cancer and Asthma, etc.
  • It is helpful in the change of our emotions.
  • It is such an important gland that survival without it is impossible.
  • It increases metabolism.
  • It stimulates the liver to convert glycogen into glucose.
  • It helps in the contraction of different kinds of arteries in the skin and internal organs but at the same time, it expands our muscles and the arteries of the heart.
  • In a state of emergency or a sudden calamity, this gland creates a sense of alertness in the body and prepares us to face squarely a dangerous situation by inculcating in us a feeling of internal strength and security.

Special Note

In order to keep this gland in sound health the following Asanas and Pranayams are greatly helpful:

  1. The seventh pose of Surya Namaskar, Janushirasan, Paschimuttanasan Konasan, Ushtrasan, Bhujangasan, Shalabhasan, Dhanurasan, and Mayurasan.
  2. Agnisar Kriya, Surya Bhedi, Kapal Bhati and Bhastrika Parnayam.

Note: Please look up Liver, Pancreas, Kidneys, and Sex-glands in our discussion of the Digestive System.