The circulatory system has several functions serving to carry food and oxygen to the cells, and to collect the metabolic wastes that are to be removed later by the kidneys. urine, and the air exhaled in the lungs, rich in carbon dioxide (CO2). Of all this work is responsible for blood, which is constantly circulating. In addition, the circulatory system has other outstanding functions: it intervenes in the body's defenses, regulates body temperature, etc.

Blood is the fluid that circulates throughout the body through the circulatory system, formed by the heart and a system of tubes or vessels, blood vessels.
Blood describes two complementary circuits called major or general and minor or pulmonary circulation ...
Blood is a liquid tissue composed of water and dissolved organic and inorganic substances (mineral salts), which form the blood plasma and three types of forming elements or blood cells: red blood cells, white blood cells and platelets. One drop of blood contains approximately 5 million red blood cells, 5,000 to 10,000 white blood cells and around 250,000 platelets.


Breathing is the process by which we enter air (which contains oxygen) into our body and we draw air rich in carbon dioxide. A living being can be several hours without eating, sleeping or drinking water, but can not stop breathing for more than three minutes. This charts the importance of breathing for our lives.

The respiratory system of humans is formed by:

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Airways: are pits nasal, pharynx, larynx, trachea, bronchi and bronchioles. The mouth is also an organ through which the air enters and exits during breathing.

The digestive tract represents a long conduit that with notable modifications, especially in its tunica mucosa, extends from the mouth to the anus. A small proximal extension of this tube is located in the cephalic region of the subject, including the oral cavity, pharynx, and esophagus, which together measure approximately 40 cm . of length. In contrast, most of the digestive tract is located in the abdomino-pelvic cavity including the stomach, small intestine, large intestine and the rectum. These structures together measure approximately 4 meters. Along the digestive tract is a layered arrangement with a mucous tunic , a muscular layer that in some areas, such as in the stomach, is complex and adventitious or a serous layer, as seen in the area of ​​the digestive tract located in the abdomino-pelvic cavity.

  • Adam Floyd