Hematopoiesis/ Heamatoposis is the process by which the body produces blood. Like they say, "Blood is Life".  Blood is the reddish fluid (though some animals have blue blood) found within the closed circulatory system of our body. Blood is very important in the human body and it has numerous functions.  which are listed below.

Function of Blood

• Transport of Nutrients
• Transport of Oxygen and Carbon IV Oxide
• Protection against germs and foreign bodies
• Protection again blood loss
• Regulation of body temperature
• Regulation of the human pH and Water content

The human blood is however made up of :

• A yellowish blood fluid known as Plasma and
• A bunch of Blood Cells

The blood plasma is a yellowish fluid which suspends the whole blood cells in it. It makes up 55% of the total blood volume containing vatious substances such as:

• Water
• Hormones
• Glucose
• Amino acids
• Fatty Acids
• Electrolytes
• Plasma proteins etc

Plasmapheresis is a medical term used to describe a therapy involving extraction, treatment and reintegration of plasma.Just like donating blood (which contains plasma and blood cells), people also donate plasma.

The blood cells of the body include:

• Thrombocyte
• Leukocyte
• Erythrocyte

The Thrombocytes are specialized cells in the blood involved in the coagulation of blood. They are also called platelets. Thrombocytes are small yellowish cells with irregular cell wall. After production and release into the blood, their lifespan is approximately 5 - 9 days. If a person lacks enough thrombocytes, he could excessive blood loss during trauma.

The Leukocyte are the defense mechanism of the body. They could be regarded as the security system of the body involve in fighting against germs and foreign bodies. They make up the immune system can also be regarded to as the white blood cells. There are five types of white blood cells in the human body involved in fighting external or foreign bodies, this could be see in case of microbes and transplant of foreign organs. They could also be seen fighting the body itself in case of leukemia. White blood cells have a lifespan of 3 to 4 days.

The Erythrocytes which are the most abundant cell of the blood. They are reddish in color, biconcave and elastic in nature. They are made up of hemoglobin which enables them in functions such as oxygen and carbon IV Oxide transport. They are the target of most parasites such as plasmodium (the malaria causing parasite). Erythrocytes or red blood cells have a life span of four months except in case of pathologies (such as malaria, sickle cell and thassalemia). 

Erythrocytes are produced inn the bone marrow, and this process of red blood cell producction is known as Erythropoiesis.

ERYTHROPOIESIS

Erythropoiesis is the production of red blood cells. It usually take up to seven days in an adult to produce a mature red blood cell.

The body produces blood from various structures of the body:

• Liver
• Marrows of Long and Flat bones
• Spleen and lymphoid organs

Liver

The liver only produced erythrocytes during intrauterine life (life before birth.) While in the uterus, the liver produced red blood cells for the growing fetus, starting from the third month of gestation. A child produces its own blood contrary to the believe that children get blood from their mother.

Spleen and lymphoid Organs

The spleen is a small organ in the abdominal cavity close to the stomach and superior to the right kidney. It produced blood along side the liver during intrauterine life but has a different function in adult. In adults, the spleen is involved in the breakdown/ destruction of old and worn out red blood cells. It has very small and tiny capillaries which can only be passed by young, healthy and elastic red blood cells. In the process of old red blood cells passing, they rupture and die. 

Bones of long and flat bones

This include the bones of the arm (humerus), thigh (femur), leg, hand, palm, ribs, skull, hip bones etc. As man grows, some of these bones looses ability to produce blood due to fat deposition. The bone left to erythropoiesis are the ribs, hip bone and femur.

Process of Blood Formation

Blood production is different in both adults and children and also uterine fetus.

Erythropoeisis in Fetus

This begin in the second month of intrauterine life whereby the fetus can no longer get nutrient by simple diffusion. Blood is made from the mesenchyme of the yolk sack.

Erythropoiesis in Babies

A baby has its own blood, it produced its own blood even right from the womb. The organ of production include the liver, spleen along side the bone marrows.

Erythropoeisis in Adult

Blood cells are produced from stem cells known as colony forming units. These stem cells are in abundance in the bone marrow, they begin to synthesize substances, develop and grow until the final product is formed. 

These are the stages of erythropoeisis:

• Proerythroblast
• Early normoblast
• Intermediate normoblast
• Late normoblast
• Reticulocyte
• Matured red blood cell

All these processes takes seven days. 

Factors responsible for Erythropoeisis 

The factors responsible for production of red blood cells include:

• Stimulating Factors: This causes or stimulate the body for the need to produce blood. These factors include hypoxia (reduced oxygen in tissue), erythropoietin (hormone stimulating the organs that produce blood to start production), thyroxine, hematopoeitic growth factors and vitamin B3, B6, C, D and E.

• Maturation Factor: This factors are necessary for the proper maturation of red blood cells. They include Vitamin B12, intrinsic factor and Folic acid.

• Factors necessary for Hemoglobin Formation: Hemoglobin is an important component of the red blood cell. These are factors needed for its formation; First class proteins and amino acids, copper, cobalt, nickel, Iron, Vitamin B2, B3 and B6.

Futher reading:

• https://en.wikipedia.org/wiki/Erythropoiesis

Image Source: [1]   - - -  [2]   - - -   [3]   - - -   [4]   - - -   [5]   - - -   [6]   

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