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Human blood



Red blood cells

What is - definition

Blood is a liquid connective tissue produced in the red bone marrow that flows through the blood veins, arteries and capillaries of vertebrate and invertebrate animals. Blood is one of the three components of the circulatory system, the other two being the heart and blood vessels.

Main functions

It is responsible for the transport of substances (nutrients, oxygen, carbon dioxide and toxins), regulation and protection of our body.

Human blood composition

In it we find the blood plasma, responsible for 66% of its volume, in addition to the red blood cells, leukocytes and platelets, responsible for approximately 33% of its composition.

Most blood plasma is made up of water (93%), hence the importance of always staying hydrated by drinking plenty of fluids. In the remaining 7% we found: oxygen, glucose, proteins, hormones, vitamins, carbon dioxide, minerals, amino acids, lipids, urea, etc.

Red blood cells, also known as red blood cells or erythrocytes, carry oxygen and carbon dioxide throughout the body. These cells last approximately 120 days, after which they are replaced by the bone marrow.

White blood cells, also called leukocytes, are responsible for defending our body. They protect our body against the invasion of unwanted microorganisms (viruses, bacteria and fungi). Quite simply, we can say that they are our "little defense soldiers".

Platelets are fragments of cells present in the blood that coagulate, thus preventing their excessive blood loss (bleeding).

They usually act when blood vessels are damaged. A simple example is the case of a needle stick, where a slight and slight loss of blood is soon stopped, thanks to the platelet plug.

Biological curiosity:

- The branch that studies the blood and its diseases is hematology.