eritrocite

Eritrocit is the Italian and Portuguese term for erythrocyte, commonly known as a red blood cell. Erythrocytes are the most abundant type of blood cell, responsible for transporting oxygen from the lungs to the body's tissues and carrying carbon dioxide back to the lungs for exhalation. They are biconcave discs, which increases their surface area for gas exchange and allows them to deform and pass through narrow capillaries.

Mature mammalian erythrocytes lack a nucleus and most organelles, maximizing the space available for hemoglobin, the protein that binds oxygen. This anucleated state also limits their lifespan, typically around 120 days, after which they are removed by the spleen and liver. The production of erythrocytes, known as erythropoiesis, occurs primarily in the bone marrow and is regulated by the hormone erythropoietin, which is produced by the kidneys in response to low oxygen levels.

The characteristic red color of blood is due to hemoglobin. When hemoglobin binds to oxygen, it becomes oxygenated and appears bright red, while deoxygenated blood is darker red. The number of erythrocytes in the blood is an important indicator of health. Low levels, known as anemia, can result from various causes and lead to fatigue and weakness due to insufficient oxygen delivery. Conversely, an abnormally high number, polycythemia, can thicken the blood and increase the risk of clotting.