How Are Blood Cells Born?
Blood cells are born in the bone marrow, specifically the red bone marrow. This process, called hematopoiesis, begins with stem cells known as hemocytoblasts. These versatile cells can develop into all types of blood cells. For example, if a hemocytoblast commits to becoming a proerythroblast, it will mature into a red blood cell.
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Hemocytoblasts: The journey begins with these pluripotent stem cells located within the bone marrow. They are the progenitors of all blood cells. (MedlinePlus Medical Encyclopedia, [Reference 11-Mar-2024])
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Commitment and Differentiation: Hemocytoblasts differentiate, or specialize, into various lineages based on the body's needs. The commitment to becoming a specific blood cell type (e.g., red blood cell, white blood cell, platelet) is a crucial step.
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Maturation: Once committed, the cells undergo a series of maturation steps. For red blood cells, this involves the production of hemoglobin, the protein that carries oxygen. This process leads to the formation of fully functional blood cells.
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Release into Circulation: Mature blood cells are released from the bone marrow and enter the bloodstream, ready to perform their vital functions.
Different Types of Blood Cells and Their Origins
While red blood cells are a primary focus, it's essential to remember that all blood cells—red blood cells, white blood cells (including lymphocytes), and platelets—originate from the hemocytoblasts in the bone marrow. After birth, most blood cell production occurs in the bone marrow. (Cleveland Clinic) Certain white blood cells, specifically lymphocytes, may also mature in other lymphatic tissues.
Life Cycle of Red Blood Cells
As noted in a concise review, the average lifespan of a human red blood cell is approximately 120 days. (SpringerLink) After this period, aged and damaged red blood cells are removed from circulation and recycled.
Conditions Affecting Blood Cell Production
Various conditions can affect blood cell production. For example, sickle cell disease causes red blood cells to become misshapen, impacting their function. (NHLBI, NIH). Premature birth can also lead to blood problems like anemia due to insufficient red blood cell production. (Mayo Clinic)
