Erythropoiesis is red blood cell (erythrocyte) production. Your bone marrow makes most of your red blood cells. Once they’re fully mature, they’re released into your bloodstream, where they transport oxygen throughout your body. Problems with erythropoiesis can result in anemia, a condition that involves not having enough red blood cells.
Erythropoiesis (pronounced “ur-i-throw-poy-EE-sus”) is your body’s process of making red blood cells (erythrocytes). Erythropoiesis ensures you have the right number of blood cells — not too few or too many. Red blood cells are important because they:
Erythropoiesis is one type of hematopoiesis. Hematopoiesis is your body’s process of making all three types of blood cells: red blood cells (erythropoiesis), white blood cells (leukopoiesis) and platelets (thrombopoiesis).
Erythropoiesis starts before people are born. This is fetal erythropoiesis. By the time people are born, erythropoiesis takes place in people’s bone marrow. Bone marrow is the spongy tissue inside of your bones.
The location of erythropoiesis changes as a fetus develops during pregnancy.
By the time you’re born, erythropoiesis happens primarily in your bone marrow.
“Medullary” refers to your bone marrow. Medullary erythropoiesis happens in your bone marrow, while extramedullary erythropoiesis happens outside your bone marrow.
Extramedullary erythropoiesis is normal at some stages of fetal development. During adulthood, extramedullary erythropoiesis is often a sign of a disease or condition affecting your bone marrow.
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With erythropoiesis, an originator cell called a hematopoietic stem cell (HSC) matures into a fully mature red blood cell, or erythrocyte. A cell advances through many stages for this to happen.
Each type of blood cell (red blood cells, white blood cells and platelets) begin as an HSC. For a red blood cell to eventually form, an HSC becomes a common myeloid progenitor (CMP) cell. A CMP may mature into a red blood cell, platelet or some types of white blood cells. A CMP that eventually becomes a red blood cell develops into a megakaryocyte-erythroid progenitor cell (MEP).
Once it’s developed into a MEP, the cell is on track to become a red blood cell. It progresses through the following stages as it develops:
Your bone marrow releases mature blood cells into your bloodstream. Once they’re in your bloodstream, your red blood cells can move oxygen from your lungs to your tissue. They can move carbon dioxide from your tissues to your lungs (to be exhaled).
It takes about a week for a red blood cell to fully mature.
Red blood cells live for approximately 120 days.
Your body’s sensitivity to oxygen levels regulates erythropoiesis. If your tissues don’t have enough oxygen (hypoxia), your body will ramp up red blood cell production. More red blood cells mean there’s more oxygen flowing to your tissues and cells.
A hormone called erythropoietin triggers erythropoiesis.
The process goes like this:
Your kidneys constantly secrete low levels of EPO to keep red blood cell production going. You lose about 1% of your red blood cells each day. Erythropoiesis replaces the red blood cells that have reached the end of their lifespan.
Your kidneys may secrete more or less EPO in response to conditions or injuries affecting your red blood cell levels.
Problems with erythropoiesis may cause you to have too few red blood cells (anemia) or too many red blood cells (erythrocytosis).
Many conditions can impact your body’s ability to make and regulate red blood cells.
A note from Cleveland Clinic
Your body continually makes new red blood cells throughout your lifetime. As red blood cells die, your body senses the changes and boosts the production of EPO and (as a result) red blood cells. Having the right amount of red blood cells is essential to maintaining a healthy supply of oxygen to your tissues. Fortunately, your body automatically regulates this process closely without any effort on your part. Your healthcare provider can recommend treatments to cure or manage many conditions that interfere with erythropoiesis.
Last reviewed by a Cleveland Clinic medical professional on 11/01/2022.
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