Human Blood Composition and Functions

A condition where the body does not have enough healthy red blood cells to carry adequate oxygen to the tissues.

Anemia caused by decreased production of red blood cells.

A type of anemia where red blood cells are abnormally small and contain less hemoglobin than normal.

The process of blood cell formation.

The production of red blood cells.

A protein found in red blood cells that carries oxygen.

A type of anemia caused by vitamin B12 or folate deficiency.

A type of anemia caused by a genetic defect in the hemoglobin molecule, resulting in abnormal red blood cells that are sickle-shaped.

A group of hereditary blood disorders characterized by abnormal hemoglobin production.

A hormone primarily produced by the kidneys that stimulates the production of red blood cells in the bone marrow.

The primary site of red blood cell production in adults, located within bones like ribs, vertebrae, and the skull.

The process by which the body stops bleeding, forming a blood clot to seal a damaged blood vessel.

The main components of haemostasis are platelets, the coagulation cascade (clotting factors), and blood vessels.

Platelets are small, cell fragments produced in bone marrow from megakaryocytes. They stick together (aggregation) and release factors that help clot formation.

Vasoconstriction narrows blood vessels, slowing blood flow. Platelets stick to the damaged area, forming a 'plug'. The coagulation cascade then forms a stable fibrin clot.

The coagulation phase is a complex series of reactions involving clotting factors (proteins) in the blood. It converts the soft platelet plug into a strong fibrin clot.

The intrinsic pathway is activated by blood components. The extrinsic pathway is activated by factors outside the blood, like damaged tissue. Both pathways merge to form a common pathway leading to fibrin clot formation.

Calcium is essential for clotting factor activation. Vitamin K is needed for the synthesis of certain clotting factors. Inhibitors like antithrombin and protein C prevent uncontrolled clotting.

Fibrinolysis is the breakdown of the fibrin clot by the enzyme plasmin. It removes clots after healing, preventing blood vessels from becoming blocked.

Haemolytic disease of the newborn (HDN) occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the mother developing antibodies against fetal red blood cells. These antibodies can cross the placenta and attack the fetus's red blood cells, causing hemolysis (destruction of red blood cells) and potential complications.

The ABO blood group system classifies blood based on the presence or absence of A and B antigens on red blood cells. People with type A blood have the A antigen, type B have the B antigen, type AB have both, and type O have neither. This system is important for blood transfusion, as receiving incompatible blood can trigger a dangerous immune response.

Rh-positive individuals have the Rh D antigen on their red blood cells, while Rh-negative individuals do not. Rh incompatibility can occur when an Rh-negative mother carries an Rh-positive fetus, leading to complications including hemolytic disease of the newborn.

Blood donation rules prioritize giving recipients their own blood group (red blood cells) whenever possible. However, in emergencies, O negative blood is considered the universal donor because it lacks A, B, and Rh D antigens, making it less likely to cause an immune response.

The intrinsic pathway is activated by factors within the blood (e.g., damaged blood vessels), while the extrinsic pathway is triggered by factors outside the blood (e.g., tissue damage). Both pathways converge on the common pathway, culminating in the formation of a fibrin clot.

Fibrinolysis is the process of breaking down a clot. It involves the activation of plasmin, an enzyme that dissolves fibrin, restoring blood flow.

The process by which the body stops bleeding, involving a series of events that lead to the formation of a blood clot.

The constriction of blood vessels at the site of injury, reducing blood flow and promoting clot formation.

Small, oval-shaped cells lacking a nucleus, vital for blood clotting.

The process of platelets adhering to the damaged blood vessel wall and then forming a sticky clump.

The final stage of haemostasis, forming a stable fibrin mesh that traps blood cells and platelets to form a clot.

A protein found in plasma that is converted into insoluble fibrin during the coagulation phase, forming the meshwork of a blood clot.

The insoluble fibrous protein that forms the meshwork of a blood clot.

A substance released from damaged tissues that initiates the extrinsic pathway of coagulation.

A series of reactions that begins with tissue factor, and ultimately leads to thrombin activation.

A series of reactions that begins with the activation of factor XII, and ultimately leads to thrombin activation.

A complex formed by FXa (activated factor X) and FVa (activated factor V), which converts prothrombin into thrombin.

An enzyme that plays a central role in coagulation by converting fibrinogen into fibrin.

A mineral essential for normal blood clotting, involved in various steps and processes of coagulation.

A vitamin vital for the production of several clotting factors in the liver, including prothrombin.

Substances in plasma that help prevent excessive clotting and keep blood flowing smoothly.

White blood cells (WBCs) are a key part of the immune system, defending the body against pathogens, removing toxins and waste, and clearing damaged cells.

Granulocytes are WBCs with granular cytoplasm, containing enzymes and other substances that help them fight infections. Examples include neutrophils, eosinophils, and basophils.

Agranulocytes are WBCs with non-granular cytoplasm and play a crucial role in specific immune responses. Lymphocytes and monocytes are examples.

Neutrophils are the most common type of WBCs, making up 50-70% of the total. They are the first responders to bacterial infections, destroying bacteria through phagocytosis.

Eosinophils are WBCs that play a key role in fighting parasitic infections and allergic reactions. They release toxic compounds to kill parasites and control inflammation.

Basophils are the least common WBCs, involved in allergic responses. They release histamine and other chemicals that promote inflammation.

Lymphocytes are a diverse group of WBCs responsible for specific immunity. They recognize and target specific pathogens, providing long-term protection against infections.

Monocytes are large, phagocytic WBCs that circulate in the blood for a short time before migrating to tissues. They differentiate into macrophages, engulfing debris and pathogens.

White blood cells that release histamine and heparin, contributing to inflammation and allergic reactions. They are the least common type of WBC, comprising less than 1% of the total.

A condition characterized by an abnormally high number of eosinophils in the blood. This can indicate parasitic infections, allergic reactions, or certain types of cancer.

White blood cells that are the largest of the leukocytes and have a large, kidney-shaped nucleus. They play a crucial role in phagocytizing (engulfing) foreign invaders and debris in tissues, differentiating into macrophages.

A type of white blood cell that is part of the body's immune system and plays a vital role in fighting infection. Lymphocytes can be broadly classified into T cells, B cells, and NK cells, each with specific roles in immune defense.

White blood cells that are crucial in cell-mediated immunity, attacking infected cells directly. They help to destroy viruses, bacteria, and other pathogens.

White blood cells that produce antibodies, playing a vital role in humoral immunity. Antibodies bind to pathogens, neutralizing them and marking them for destruction.

White blood cells that are part of the innate immune system and play a vital role in killing infected cells and tumor cells. They act as a first line of defense against pathogens and abnormal cells.

A group of leukocytes (white blood cells) that lack the noticeable granules found in other types. They include monocytes and lymphocytes, and play crucial roles in immune defense.