Blood(3)

Comprehensive vocabulary flashcards covering the components, cellular elements, life cycles, counts, hemostatic mechanisms, and blood typing concepts from the Blood lecture notes.

Blood

A type of connective tissue that transports vital substances (such as nutrients, oxygen, wastes, and hormones) between body cells and the external environment, maintains the stability of interstitial fluids, and distributes heat.

Plasma

The clear, straw-colored liquid portion of the blood that suspends cells and platelets, making up about $55\%$ of blood volume and composed of approximately $92\%$ water.

Hematopoiesis

The process of blood cell production that originates in red bone marrow from hemocytoblasts or hematopoietic stem cells.

Hemocytoblasts

Stem cells in the red bone marrow that give rise to all blood cells and differentiate into lymphoid or myeloid stem cells in response to hematopoietic growth factors.

Erythrocytes

Biconcave disc-shaped red blood cells that lack nuclei and mitochondria at maturity, produce ATP through glycolysis, and are approximately one-third hemoglobin by volume.

Oxyhemoglobin

A hemoglobin molecule that is chemically combined with oxygen.

Deoxyhemoglobin

A hemoglobin molecule from which oxygen has been released.

Erythropoiesis

The formation of red blood cells, occurring initially in the embryonic yolk sac, liver, and spleen, and carried out almost exclusively by red bone marrow after birth.

Erythropoietin

A hormone released primarily by the kidneys and liver in response to low blood oxygen that stimulates red blood cell production via a negative feedback mechanism.

Biliverdin

A green pigment formed by the breakdown of the iron-containing heme portion of hemoglobin during red blood cell destruction.

Bilirubin

An orange pigment converted from biliverdin that is secreted into the bile.

Ferritin

The storage protein complex in the liver that holds iron conserved during the destruction of worn or damaged red blood cells.

Granulocytes

A category of white blood cells with granular cytoplasm, produced in red bone marrow, that are about twice the size of red blood cells and have an average lifespan of about $12\,\text{hours}$.

Neutrophils

Granulocytes with lobed nuclei that comprise $54\%$ to $62\%$ of leukocytes; they are the first to arrive at an infection site to phagocytize bacteria, fungi, and viruses.

Eosinophils

Granulocytes with bi-lobed nuclei comprising $1\%$ to $3\%$ of leukocytes that defend against parasitic worm infections and become elevated during allergic reactions.

Basophils

Granulocytes comprising less than $1\%$ of leukocytes that migrate to damaged tissues to release histamine (promoting inflammation) and heparin (inhibiting blood clotting).

Agranulocytes

A category of white blood cells that lack visible cytoplasmic granules, consisting of monocytes and lymphocytes.

Monocytes

The largest type of blood cells ($2$ to $3$ times the size of RBCs), comprising $3\%$ to $9\%$ of leukocytes, that leave the bloodstream to become active phagocytic macrophages.

Lymphocytes

Agranulocytes comprising $25\%$ to $33\%$ of leukocytes that have a large spherical nucleus and differentiate into T cells (attacking microbes and abnormal cells) and B cells (producing proteins that attach foreign molecules).

Diapedesis

The process by which leukocytes squeeze through capillary walls to leave the bloodstream and enter interstitial tissue spaces.

Ameboid Motion

A form of self-propulsion used by white blood cells to move through interstitial spaces once outside blood vessels.

Positive Chemotaxis

The movement of leukocytes toward damaged cells in response to chemical attractants released by the damaged tissues.

Leukocytosis

A condition characterized by an elevated total white blood cell count exceeding $10{,}000/\mu\text{L}$, often seen during infections, vigorous exercise, or body fluid loss.

Leukopenia

A condition characterized by an abnormally low white blood cell count below $5{,}000/\mu\text{L}$, associated with diseases like typhoid fever, influenza, measles, chickenpox, or AIDS.

Platelets (Thrombocytes)

Non-nucleated cytoplasmic fragments of megakaryocytes measuring about half the size of an RBC, functioning in hemostasis and releasing serotonin.

Thrombopoietin

The hormone that stimulates hemocytoblasts in red bone marrow to proliferate and differentiate into megakaryocytes and platelets.

Albumins

The smallest and most abundant plasma proteins (making up $60\%$ of total plasma proteins) that help maintain the colloid osmotic pressure of blood.

Globulins

Plasma proteins making up $35\%$ of plasma proteins, consisting of liver-synthesized alpha and beta globulins (transporting lipids and fat-soluble vitamins) and lymphatic-derived gamma globulins (antibodies).

Fibrinogen

A soluble plasma protein making up $4\%$ of plasma proteins that is converted into insoluble fibrin threads during blood coagulation.

Hemostasis

The physiological process that stops bleeding from injured blood vessels through vascular spasm, platelet plug formation, and blood coagulation.

Extrinsic Clotting Mechanism

A clotting cascade triggered when blood contacts damaged blood vessel walls or tissues outside blood vessels, initiated by tissue thromboplastin (factor III).

Intrinsic Clotting Mechanism

A blood clotting pathway triggered without external tissue damage when blood contacts foreign surfaces (such as collagen), initiated by Hageman factor XII.

Serum

The clear fluid that is squeezed out of a retracting blood clot, consisting of blood plasma minus fibrinogen and most other clotting factors.

Plasmin

An active enzyme converted from plasminogen that digests fibrin threads to break down blood clots.

Antithrombin

A plasma alpha globulin that limits blood coagulation by binding to and inactivating thrombin, preventing it from converting fibrinogen to fibrin.

Agglutination

The clumping of red blood cells caused by a specific reaction between red blood cell surface antigens and corresponding plasma antibodies.

Universal Donor

Type O negative ($\text{O}^-$) blood, which lacks A, B, and Rh antigens on its red blood cell membranes and can therefore be donated to recipients of any blood type.

Universal Recipient

Type AB positive ($\text{AB}^+$) blood, which lacks anti-A and anti-B antibodies in plasma and possesses the Rh antigen, allowing the person to safely receive RBCs of any blood type.

Erythroblastosis Fetalis

Hemolytic disease of the newborn that can develop when an Rh-negative mother carries an Rh-positive fetus.