Hematopoietic Stem Cells: In living organisms, a specialized system that consist of blood and its progenitors are referred to as the hematopoietic system.

In particular, this system is made up of cells with specialized functions such as the red blood cells (for carrying oxygen to tissues), white blood cells (for immune defense against pathogens, and foreign agents), platelets (for blood clotting), macrophages and lymphocytes (also for immune defense).

However, many of the said blood cells are temporary and need to be replaced with new ones continuously. But fret not because a single cell can solve the problem!

Every day, almost billions of new blood cells are synthesized within the body with each coming from a specific progenitor cell called the hematopoietic stem cell.

How to pronounce Hematopoietic Stem Cells?

What is Hematopoiesis?

The formation of all kinds of blood cells including creation, development, and differentiation of blood cells is commonly known as Hematopoiesis or Haemopoiesis.

All types of blood cells are generated from primitive cells (stem cells) that are pluripotent (they have the potential to develop into all types of blood cells).

Also referred to as hemocytoblasts, hematopoietic cells are the stem cells that give rise to blood cells in hematopoiesis.

Where Does Hematopoiesis Occur?

In a healthy adult, hematopoiesis occurs in the bone marrow and lymphatic tissues, where 1000+ new blood cells (all types) are generated from the hematopoietic stem cells to main the steady-state levels.

Where Are Hematopoietic Stem Cells Found?

They can also be found in the umbilical cord and in the blood from the placenta.

Who Discovered Hematopoietic Stem Cells?

It was long believed that the majority of hematopoiesis occurs during ontogeny (origination and development of organism) and that the mammalian hematopoietic system originated from the yolk sac per se.

Functions of Hematopoietic Cells

As alluded to earlier, blood cells and blood cell components are formed in a process called hematopoiesis.

Coming from the Greek words hemato and poiesis which mean blood and to make respectively, hematopoiesis occurs in the bone marrow and is responsible not only for the synthesis but also the multiplication, and differentiation of blood cells.

Shown below is a diagrammatic illustration of the different blood cell types that hematopoietic cells can give rise to:

Clinical uses of Hematopoietic Stem Cells

The mammalian blood system showcases the equilibrium between the functions of hematopoietic stem cells. Intensive studies have already shown the structures and molecules that control these stem cells, but the exact picture of the underlying molecular mechanisms is still unclear.

Above everything else, it is important to note that such issues are not just of academic interest but can also be relevant in devising future novel methods of diagnosing and treating various diseases associated with cells.

Key References

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Hematopoietic Stem Cells | Hematopoiesis | Properties & Functions