The cardiovascular or circulatory system comprises the blood, the heart, and the blood vessels.
Blood is a specialized fluid comprising cells in a liquid …
Whole blood consists of the blood plasma, a fluid extracellular matrix, and formed elements, including cells and cell fragments.
Blood plasma, which makes …
Hematopoiesis, or hemopoiesis, is the production of the formed elements in blood from common progenitors, called hematopoietic stem cells, or HSCs.
During …
Hemangioblasts, the multipotent stem cells of mesodermal origin, give rise to hematopoietic stem cells or HSCs.
The HSCs undergo hematopoiesis to produce …
Hematopoietic growth factors are a group of regulatory and signaling molecules that influence the differentiation of hematopoietic stem cells, or HSCs.
…
Hemoglobin is a tetrameric globular protein consisting of two alpha and two beta polypeptide chains.
Each of these chains has an iron-containing heme …
The circulating erythrocytes frequently squeeze through blood capillaries, damaging their plasma membrane due to constant friction.
After about 100 to 120 …
Erythrocyte disorders are broadly categorized into anemic and polycythemic conditions.
Anemia develops due to the low oxygen-carrying capacity of the …
A healthy individual has about 4,500 to 11,000 leukocytes or white blood cells per microliter of blood, accounting for about 1% of blood volume.
Unlike …
Leukocytes containing cytoplasmic granules are classified as granular, while those with relatively clear cytoplasm are termed agranular.
All granulocytes …
Leukocyte disorders are characterized by either leukopenia, an abnormally low leukocyte count, or leukocytosis, a very high leukocyte number.
Bone marrow …
A microliter of blood contains 150,000 to 400,000 small, disc-shaped cell fragments called platelets or thrombocytes.
These fragments originate in the …
Hemostasis is a series of rapid, defensive reactions triggered to stop excessive bleeding and promote healing after a vascular injury.
It is a highly …
Hemostasis begins with a vascular spasm, also known as the vascular phase. It starts immediately after any damage to a blood vessel, causing a sudden …
In an injured blood vessel, the platelet phase – which overlaps with the vascular phase – begins about 15-20 seconds after the onset of vascular spasm.
As …
Coagulation or clotting is the last hemostasis phase. It involves a series of chemical reactions to form a blood clot, reinforcing the initial platelet …
The extrinsic and intrinsic pathways of coagulation involve reaction cascades of clotting factors. They merge into the common pathway, eventually forming …
The activated platelets in a blood clot extend projections and interact with other platelets and fibrin fibers.
Within 30 to 60 minutes, the contractile …
The ABO blood group system is based on the presence of specific antigens or agglutinogens on the red blood cells, or RBCs, and antibodies or agglutinins …
The antigens A, B, and Rh on the surface of red blood cells serve as the foundation for blood grouping.
When these antigens come in contact with their …
A blood transfusion is a medical procedure to replace lost whole blood or its components due to injury, surgery, or treatment for conditions like anemia …
The cardiovascular system regulates erythrocyte numbers for optimal oxygen transport. It also prevents erythrocyte over-proliferation, maintaining blood …
Clonal hematopoiesis is a prevalent age-associated condition that results from the accumulation of somatic mutations in hematopoietic stem and progenitor …
The bone marrow (BM) is the soft tissue found within bones where hematopoiesis, the process by which new blood cells are generated, primarily occurs. As …
Robust point-of-care methods are required to estimate anemia at the population level. The accurate methods are lab-based and cannot be used at the point …
