Anatomy And Physiology

Anatomy Physiology

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Erythrocyte and us

Erythrocytes are also known as red blood cells (RBCs). They are cells normally found in animals and are highly specialised in transport of oxygen and carbon dioxide. Due to the differences and the complexities between the many types of erythrocytes, in the interest of this article we will be focused on the human erythrocytes.
The human erythrocytes do not contain a nucleus; however erythrocytes in organisms such as the turtle have a nucleus. The nucleus is lost in a process know as haemopoeisis, this process occurs in the erythrocyte's formation in the bone marrow. During haemopoeisis most of the organelles are also degraded and mitochondria are lost altogether.
Due to the speciality of the erythrocytes, it does its job comfortably in the internal environment of the organism.

Function of erythrocytes

The main job of erythrocytes is to transport oxygen to the different part of the body and to carry carbon dioxide to the lungs for exhaling. Human erythrocytes are biconcave in shape (as seen on my model) which combined with the loss of organelles and the nucleus greatly enhances its ability to exchange O2 and CO2.

Structures of erythrocytes

The only structures visible under a light microscope are the cell membrane and the cytoplasm. In erythrocytes, the cell membrane is very important as it allows gas transfer between the cell and its external environment.
Since human erythrocytes do not have a nucleus and do not have most of the organelles, the only structures not visible under a microscope worth a mention are its cytoskeletons and a substance named haemoglobin. It may come as a surprise when I tell you that cytoskeletons in erythrocytes are specialised so that they dissolve when the erythrocytes are moving through tiny gaps in the blood capillaries and reform once it's through the gap.
Haemoglobin is made of two parts, haem which is an iron containing pigment, and globin which is a protein. Haemoglobin is responsible for the metallic taste of blood. Haemoglobin is the main function unit of the erythrocyte. It is responsible for oxygen uptake in the lungs, carriage in the erythrocytes and release in other tissues. It also carries carbon dioxide as carbaminohaemoglobin. Haemoglobin is also partly responsible for maintaining the blood's pH levels.

Fun facts

Adult humans have roughly 23 1013 erythrocytes at any given time.
People living at high altitudes with low oxygen tension will have more erythrocytes.
In the camel family Camelidae, the erythrocytes are oval shaped.
the spleen in dogs stores a large numbers of red blood cells which are dumped into the blood during times of exertion stress, yielding a higher oxygen transport capacity.
The diameter of a typical human erythrocyte disk is 68 m, much smaller than most other human cells.
A typical erythrocyte contains about 270 million haemoglobin molecules.

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