Specimen Catalog

How functions the human body?

The body lives thanks to different systems (respiratory, digestive, circulatory, nervous, muscular and skeletal, reproductive). This is the composition of the making of the global set. Organs and systems relate to each other in a coordinated way.

What Systems has the body?

  • The respiratory system
  • The digestive system
  • The circulatory system
  • The nervous system
  • The muscular and skeletal system

The respiratory system

Breathing allows men 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.

What is the mechanism of breathing?

The air, loaded with oxygen in the course of inspiration.

Once in the lungs, the air is “unloaded” from its oxygen in the alveoli, located behind the bronchioles.

The pulmonary alveoli are very small bags filled with air and having a very thin wall at the level of which respiratory gas exchange takes place. The very large number of pulmonary cells allows an absolutely astronomical total exchange surface of about 100m².

The cells swell with air at the inspiration and empty when exhaling. The thin wall is covered with very numerous and very fine blood vessels, the capillaries through the wall of which real gas exchange is realized.

Moreover, in order to protect the body, cells called “macrophages” digest dust and microbes thanks to the enzymes they contain in the pulmonary alveoli.

Oxygen will then “enrich” the blood.

During the expiry, the wastes, in particular carbon dioxide, are “recovered” during this gas exchange.

Breathing is an automatic and unconscious phenomenon. At rest, the average breathing rate or frequency of an average adult is 16 breaths per minute.

How many Liters of air uses an adult?

Every day, an adult inhales about 8000 liters of air (about 0.5 liters of air by inspiration).

The digestive system

The digestive system allows, thanks to several organs, to take the food, to digest it (to transform the food into energy and nutrients for the body) and to evacuate the surplus.

We consider 3 parts in the digestive system: the elements of the oral cavity, the elements of the digestive tract and finally, the accessory glands.

Composition and role of the elements of the oral cavity (the mouth):

The lips: fleshy and pigmented parts around the mouth and covering the teeth. No real role in the digestive system.

Teeth: used to cut food (incisors), chewing and grinding (molars and premolars) and shredding (canines).

The tongue: muscle (the strongest in relation to its size) very vascularized playing a role in chewing and swallowing.

The salivary glands: organs that are responsible for the manufacture and excretion of saliva. The role of saliva is to moisten the mucous membranes of the upper digestive system, to participate in the first stages of digestion and to facilitate the progression of food.

The pharynx: aero-disgestive junction between the airways and the digestive tract. Regarding its role at the digestive level, it is involved in swallowing.