Question

how does the respiratory system provide oxygen to the body?

Answer 1

There are two systems in the body that are related to oxygenation. The cardiovascular system and the respiratory system. We will deal with how the respiratory system is involved in oxygenation.

When we breathe in, oxygen rich air enters the lungs after passing through the nose, larynx and  trachea. From the trachea this oxygen rich air goes to the left and right main bronchi and then further downward to reach the alveoli. The alveoli are the endpoint at which the oxygen rich air reaches.

The lung has rich blood supply and the blood vessels in lungs dvide till they become small capillaries which lie adjacent to the alveoli. The alveolocapillary membrane is very this and gases can freely pass through by the process of diffusion.

Energy production in the body requires oxygen and gives carbon dioxide as a byproduct.

So, when we breathe in with the help of diaphragm, oxygen rich air rushes in. This happens due to sudden drop in the pressure within lungs which leads to the flow of air inside. Once this oxygen reaches alveoli, it passes through the alveolicapilary membrane and attaches the Red blood cells in the blood. From there, they are transported to all parts of the body. Maanwhile carbondioxide passes into the alveoli and when we exhale, it passes out into the atmosphere. I hope this image (self-made) will make it clearer

02 CO2 CAPILLARY LUNGS ALVEOLI