The human body is a chemical factory that transforms and consumes energy. The energy contained in food is pre-digested by saliva and then sent to the stomach where it is broken down by digestion into various elements. In the intestine, energy (sugars) is recovered and sent to the blood. Unused materials are disposed of. The heart, the circuit pump, sends blood full of oxygen and energy to different parts of the body to supply the muscles.
The body lives thanks to different systems (respiratory, digestive, circulatory, nervous, muscular, and skeletal, reproductive). Each system is made up of several organs that work together for the same function. Organs and systems relate to each other in a coordinated fashion.
1. The respiratory system
Breathing allows humans to recover the oxygen they need to survive and to reject gaseous waste such as carbon dioxide. The breathing mechanism requires the participation and collaboration of several organs.
The mechanism of respiration
Breathing is an automatic and unconscious phenomenon. The oxygen-laden air enters our lungs during inspiration. Once in the lungs, the air “discharges” its oxygen into the pulmonary alveoli, located at the end of the bronchioles.
The pulmonary alveoli
The pulmonary alveoli are tiny bags filled with air and have a very thin wall at the level of which the respiratory gas exchanges take place.
2. The digestive system
The digestive system makes it possible, thanks to several organs, to take food, to digest it (transform food into energy and nutrients for the body), and to evacuate the surplus.
We consider three parts in the digestive system: the elements of the oral cavity, the elements of the digestive tract, and, finally, the annex glands.
The essential role of the digestive system is to assimilate, absorb nutrients in the blood and lymphatic circulation, and eliminate elements that cannot be assimilated.
3. The circulatory system
The circulatory system, or cardiovascular system, is a real, pervasive, and very precise network. The heart and the vessels constitute this apparatus, which irrigates the various tissues of the human body.
Blood vessels, veins, arteries leave the heart, which acts as a pump and carries blood throughout the body. They provide oxygen, nutrients, and hormones essential to our entire body.
The blood which carries oxygen and the nutrients necessary for the life of all the cells of the body, circulates between the heart and the organs, by a very dense network of arteries and veins.
4. The nervous system
The nervous system is a network system made up of the sense organs, nerves, brain, spinal cord, meninges. It coordinates muscle movements, controls the functioning of organs, conveys sensory and motor information, and regulates the intellect.
The human nervous system sends, receives and processes nerve impulses. All the muscles and organs in the body depend on these nerve impulses to function.
5. The muscular and skeletal system
The muscular and skeletal system is made up of muscles, bones, and joints. The human body is made up of over 600 muscles and 200 bones and bone tissues.
Muscles are generally attached to bones and joints. The role of bones is to protect and support the different parts of the body. The skeletal muscles are attached to the bones by the tendons, and when they contract, they cause the bones to move and make the movement. Also, blood cells are produced in the red bone marrow of certain long bones.
Energy for body functioning!
The human body needs the energy to keep organs functioning, to provide sufficient temperature, to allow efforts to be made, and to transform food into a form that organs can use.