The lungs are made of soft, spongy and elastic tissues. The left lung is narrower and smaller than the right  one.  They’re responsible for providing oxygen to capillaries and exhaling carbon dioxide. The lungs has network of bronchioles, alveoli, capillaries, arteries and veins.

The respiratory system consists of the following organs:

Nose

Pharynx

Larynx

Traches

Bronchus

Bronchioles

Lungs

Diaphragm

Intercostal muscles

Pulmonary vein

Pulmonary artery

The pulmonary artery transports blood from the heart to the lungs. While most major arteries branch off from the aorta. The main pulmonary artery extends from the right ventricles of the heart and branches into left and right pulmonary arteries.

Respiration is the process of inhalation of atmospheric air into lungs due to the contraction of intercostal muscles and oxidizing food to produce energy and throwing out carbondioxide to sustain life. When air enters the lungs, chest expands along with the lungs. The air pressure in the lungs becomes lesser than outer atmospheric pressure and the air enters into lungs. From the lungs carbondioxide gas is expelled out through the same route which completes the respiration.

Respiration is an essential and important process in all living organisms. It helps in the exchange of gases and provide oxygen which is very important for the survival of most of the life forms on earth. Respiration is something we all know about as it is a visible and regular process, one which we experience with every breath. An adult breathes for about 18-20 times in a minute in rest condition. Similarly, the rate of breathing increases when we involve in games, sports and during anxiety, anger, happiness, etc.