Erythropoesis - Physiology ; Sites and Stages
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- čas přidán 16. 01. 2022
- Erythropoiesis is the process by which red blood cells (erythrocytes) are produced.
On average, the body produces an astounding 2.5 billion red cells/kg/day. Erythrocytes arise from a complex line of cells, and their rate of production is tightly regulated to ensure adequate but not excessive numbers of red blood cells are produced.
Sites of Erythropoiesis
The site of erythropoiesis changes throughout life. In the very early foetus, it occurs in the yolk sac. From 2 - 5 months’ gestation it occurs in the liver and spleen before finally establishing in the bone marrow from about 5 months’ gestation.
In children, erythropoiesis can occur in the bone marrow of most bones. However, in adults, it only occurs in the bone marrow of the vertebrae, ribs, sternum, sacrum, pelvis and proximal femur.
When erythropoiesis is inadequate in the bone marrow, this can trigger extramedullary haematopoiesis - i.e. haematopoiesis occurring outside the marrow. This is commonly seen in haemoglobulinopathies, in particular thalassaemias and myelofibrosis.
Stages of Erythropoiesis
The production of all blood cells begins with the haemocytoblast, a multipotent haematopoietic stem cell. Haemocytoblasts have the greatest powers of self-renewal of any adult cell. They are found in the bone marrow and can be mobilised into the circulating blood when needed.
Some haemocytoblasts differentiate into common myeloid progenitor cells, which go on to produce erythrocytes, as well as mast cells, megakaryocytes and myeloblasts.
The process by which common myeloid progenitor cells become fully mature red blood cells involves several stages. First, they become normoblasts (aka eryhthroblasts), which are normally present in the bone marrow only.
Secondly, they lose some organelles and their nucleus as they mature into reticulocytes, which can be thought of as immature red blood cells. Some of these are released into the peripheral circulation.
Finally, reticulocytes lose their remaining organelles as they mature into erythrocytes, which are fully mature red blood cells. These normally survive for around 120 days.
During this maturation process, there is nuclear extrusion - i.e. mature erythrocytes have no nucleus. Nucleated red blood cells present in a sample of bone marrow can indicates the release of incompletely developed cells. This can occur in pathology such as thalassaemia, severe anaemia or haematological malignancy.
Anyone else one hour before exam?
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same here
I'm five minutes before exam
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Me 😂
I think u referred from Sembulingam physiology book 📖📚
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Darun, neat and clean
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Infact you murdered it,I really really enjoyed it,pls when is leukopoiesis and thrombopoiesis own coming out I will love to have same explanation of it in this erythropoiesis way ma
Thanks
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Means Alot.
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Most welcome 😊💗
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wwhat does Reticular network do\
Tq mam💖
Can I get notes?
Good lecture
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Can I get ur notes pdf?
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Provide this in pdf
I love you ❤
Tq ❤
Learning physiology in learning anatomy😂
Iski pdf h kya
Mam plz iska pdf link dedo
Anyone one day before the exams ?
mam plz uplode leukopoiesis and thrombopoiesis video
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Mam please provide this in pdf please
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Assalamualaikum mam
Ap kahan se hu mam
Apne apna MBBS kahan se kiya
Reticular network is present in cytoplasm or nucleus ? 🙂
Nucleus
Yes
Good morning. I don’t know the answer to a question. Can you help?Why erythrocytes live 120 days, leukocytes and platelets live 2-5 days?
Why is that?
Because erythrocytes are in millions and platelets and WBC are in thousands and lakhs, so erythrocytes live more than wbc and platelets
RBC live only 120 days because- Rbc doesnot have nucleus it cannot synthesize proteins needed for vita pathways(energy production) in addition to this its membrane looses integrity, moreover due to deficiency of enzymes for maintaining high level of intracellular potassium while pumping sodium out of the cell- intracellular sodium increases and potassium decreases , selective permeability of membrane is lost, water enters the cell, the cells becomes spherical and are not able to squeeze through narrow spaces of spleen, therefore get trapped by macrophages and get lysed within macrophages.
Therefore the average RBC has sufficient enzyme function to live 120 days.
Reference:-
Rodak-Text book of hematology .
Chapter 8-erythrocyte production and destruction.
Night before my internal exam 11th July,2022
2020?
Me again before my 3rd internal 2nd December, 2022
Tq so much mam 😇☺️
❤ like this class and thanks to the creator... from my heart 💜
👏👏👏
Mam pdf
I am 2nd year student of bds. I want to pursue mbbs.. That's my only dream.. I am 21 now. Shall I once more try for neet?
What's your number and rank in neet exam .
Pdf
Anyone else 1 week before exam ?
Ye nots mil skta h pdf ,ppt me reply
❤️
Mam i request you do for 1st yr all topics & all chapters for all 3 subjects plz mammmmmmmmmmm😊😊😊😊😊😊😊😊😊😊😊
As soon as possible mam
One night before exam😅
👍🥰
yep "RBS"
Anyone else in exam
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Legend paper wali raat daikhte hue😂
Mam please
Prierythorblast it's network is chromatin network 😂 no reticular network
Clarity🤌🤌
Thank you🩶
thank you mam
Tq mam
You're welcome, keep watching ❤️