Blood Cell Formation + Storage of Chemical Energy
Bone Marrow-There are two types of Bone marrow; red bone marrow and yellow bone marrow.
Red Bone Marrow-
Structure
Although all bone marrow is red at birth by the time the human is fully grown the red bone marrow percentage is around half and is restricted to specific areas of the body. In an adult human red bone marrow is found in the flat bones (skull, ribs, vertebrae, scapula, sternum) and inside the metaphyseal and epiphyseal
areas of long bones (femur, fibula, humerous) when the area is trabecular bone(spongy/ cancellous).
Function
Red bone marrow produces all of the red blood cells, all of the platelets and most of thewhite blood cells (some white blood cells are produced in the liver and the spleen).
When babies are still in the womb and at birth all of the bone marrow in their bodies is red. As humans grow older the amount of red bone marrow in their body shortens to around half as the other half has been converted into yellow bone marrow. This type of bone marrow contains the hemopoietic and stromal stem cells. Red bone marrow has a much higher percentage of hemopoietic stem cells which allow the red bone marrow to produce new red blood cells, white blood cells and platelets. The process of producing new blood cells is called Haematopoiesis.
Example of White blood cell formation-
When there is a lack of white blood cells the body releases proteins into the bone marrow that signal the stem cells to start producing white blood cells.
Granulocyte-Colony Stimulation Factor (G-CSF) is released to stimulate the stem cells to produce Neutrophils (white blood cells that combat infectious
bacteria). Once G-CSF has stimulated the stem cells, the process to become adult white blood cells takes up to 10 days and goes through 2 phases.
In the first phase (which takes around 6 days) the stem cells divide while still developing, this is done to maximize white blood cell production
efficiency (because white blood cells only last hours in the body one released from the bone marrow. During the second phase (which takes around 4 days) the cells continue to develop but can no longer divide. Finally the Neutrophils are released into the bloodstream, where they combat infectious
bacteria.
Example of blood cell production- A person has been struck on the head and is losing blood (and oxygen stored in the blood cells). The body triggers the
kidneys to release the hormone erythropoietin, this hormone activates the bone marrow to produce red blood cells (for oxygen), white blood cells (to oppose
infections) and platelets to heal the wound.
Yellow Bone Marrow
Structure-
As humans grow older the red blood marrow in the body is converted into yellow bone marrow. This helps explain why as human grow older they become increasing prone to infections and take longer to heal from injuries due to a lack of white blood cells, platelets and red blood cells produced in red bone marrow.
Yellow bone marrow is foiund inside long bones (humerous, tibia, femur) in the hollow area of the diaphyseal.
Function
One function of yellow bone marrow is that it can be converted back into red bone marrow when there is a lack of blood cells.
Yellow bone marrow also includes adipose cells(fat cells). The yellow bone marrow stores the adipose cells as they are a source of lipids and can be used when there is a lack of energy in the body.
Red Bone Marrow-
Structure
Although all bone marrow is red at birth by the time the human is fully grown the red bone marrow percentage is around half and is restricted to specific areas of the body. In an adult human red bone marrow is found in the flat bones (skull, ribs, vertebrae, scapula, sternum) and inside the metaphyseal and epiphyseal
areas of long bones (femur, fibula, humerous) when the area is trabecular bone(spongy/ cancellous).
Function
Red bone marrow produces all of the red blood cells, all of the platelets and most of thewhite blood cells (some white blood cells are produced in the liver and the spleen).
When babies are still in the womb and at birth all of the bone marrow in their bodies is red. As humans grow older the amount of red bone marrow in their body shortens to around half as the other half has been converted into yellow bone marrow. This type of bone marrow contains the hemopoietic and stromal stem cells. Red bone marrow has a much higher percentage of hemopoietic stem cells which allow the red bone marrow to produce new red blood cells, white blood cells and platelets. The process of producing new blood cells is called Haematopoiesis.
Example of White blood cell formation-
When there is a lack of white blood cells the body releases proteins into the bone marrow that signal the stem cells to start producing white blood cells.
Granulocyte-Colony Stimulation Factor (G-CSF) is released to stimulate the stem cells to produce Neutrophils (white blood cells that combat infectious
bacteria). Once G-CSF has stimulated the stem cells, the process to become adult white blood cells takes up to 10 days and goes through 2 phases.
In the first phase (which takes around 6 days) the stem cells divide while still developing, this is done to maximize white blood cell production
efficiency (because white blood cells only last hours in the body one released from the bone marrow. During the second phase (which takes around 4 days) the cells continue to develop but can no longer divide. Finally the Neutrophils are released into the bloodstream, where they combat infectious
bacteria.
Example of blood cell production- A person has been struck on the head and is losing blood (and oxygen stored in the blood cells). The body triggers the
kidneys to release the hormone erythropoietin, this hormone activates the bone marrow to produce red blood cells (for oxygen), white blood cells (to oppose
infections) and platelets to heal the wound.
Yellow Bone Marrow
Structure-
As humans grow older the red blood marrow in the body is converted into yellow bone marrow. This helps explain why as human grow older they become increasing prone to infections and take longer to heal from injuries due to a lack of white blood cells, platelets and red blood cells produced in red bone marrow.
Yellow bone marrow is foiund inside long bones (humerous, tibia, femur) in the hollow area of the diaphyseal.
Function
One function of yellow bone marrow is that it can be converted back into red bone marrow when there is a lack of blood cells.
Yellow bone marrow also includes adipose cells(fat cells). The yellow bone marrow stores the adipose cells as they are a source of lipids and can be used when there is a lack of energy in the body.