The nutrition is the set of processes by which the body gets different substances necessary for life, providing energy and necessary elements for structures and proper functioning of the body.
The processes involved in nutrition are:
- Digestion. The digestive system is responsible for introducing food into the body, and transforming it into simple nutrients that can be used by cells.
- Breathing. The respiratory system is responsible for obtaining the oxygen necessary for the cells and eliminating CO2 from cellular metabolism.
- Circulation. The circulatory system carries nutrients, gases, waste products and other substances, linking all the cells of the body together.
- Excretion. The excretory system eliminates waste products from cellular metabolism, transported by the circulatory system, filtering the blood and expelling them through the urine.