Circulatory System: Blood Components, Hemostasis, and Blood Typing Flashcards

Vocabulary flashcard set covering blood components, plasma proteins, erythrocyte function, blood typing, leukocyte classification, platelets, and hemostasis.

Erythrocytes (RBCs)

Biconcave blood cells lacking a nucleus and mitochondria that contain high amounts of hemoglobin and function primarily to transport $O_2$ and $CO_2$.

Leukocytes (WBCs)

Nucleated blood cells with organelles that provide immune defense and protection, functioning primarily in tissues after leaving the bloodstream.

Platelets (Thrombocytes)

Small cell fragments ($2\text{--}4\,\mu\text{m}$ in diameter) without a nucleus, derived from megakaryocytes, that play a central role in hemostasis and blood clotting.

Blood Plasma Composition

The liquid matrix of blood, constituting $47\text{--}63\%$ of total blood volume, consisting of $90\%$ water, $9\%$ plasma proteins, and $1\%$ other solutes.

Albumin

The most abundant plasma protein ($60\%$), synthesized by the liver, which maintains blood fluid balance, blood volume, and blood viscosity.

Globulins

Plasma proteins ($36\%$) produced by plasma cells that function as antibodies to provide immune protection.

Fibrinogen

A soluble plasma protein ($4\%$) synthesized by the liver that is converted into insoluble fibrin threads during blood coagulation.

Blood Viscosity

The thickness or resistance to flow of blood, which is approximately $2\times$ greater than water due to plasma proteins like albumin.

Blood Osmolarity

The concentration of dissolved particles in the blood that determines its water-pulling power, with a normal value of approximately $300\,\text{osmoles}$ (isotonic).

Erythropoiesis

The process of red blood cell production occurring in the red bone marrow, taking about $3\text{--}5\,\text{days}$ to complete.

Erythropoietin (EPO)

A hormone released primarily by the kidneys ($85\%$) and liver ($15\%$) in response to hypoxemia to stimulate red bone marrow to produce RBCs.

Hemolysis

The rupture and breakdown of old or fragile red blood cells (after their $\sim 120\,\text{day}$ lifespan), carried out by macrophages in the spleen and liver.

Carbonic Anhydrase (CA)

An enzyme in erythrocyte cytoplasm that catalyzes the conversion of carbon dioxide and water into carbonic acid: $CO_2 + H_2O \rightarrow H_2CO_3$.

Hematocrit (Hct)

The percentage of total blood volume composed of red blood cells, normally $42\text{--}52\%$ in men and $37\text{--}48\%$ in women.

Polycythemia

A condition characterized by an excess of red blood cells, causing increased blood viscosity, blood volume, and blood pressure.

Anemia

A deficiency of red blood cells or hemoglobin leading to reduced oxygen delivery to tissues, decreased blood viscosity, and fatigue.

Agglutinogens

Surface antigens (glycoproteins and glycolipids) located on red blood cell membranes that determine ABO and Rh blood types.

Agglutinins

Antibodies present in blood plasma (such as Anti-A or Anti-B) that react against foreign RBC antigens.

Agglutination

The clumping reaction that occurs when plasma agglutinins bind to corresponding foreign agglutinogens on red blood cells.

Hemolytic Disease of the Newborn (HDN)

A condition in which maternal Anti-D antibodies cross the placenta and attack the RBCs of an $Rh^+$ fetus in an sensitized $Rh^-$ mother.

Neutrophils

The most abundant granulocytes ($1\text{st}$ in abundance) whose primary function is to fight bacterial infections.

Lymphocytes

Agranulocytes ($2\text{nd}$ in abundance) that provide immune defense, destroy infected/cancer cells, produce antibodies, and serve immune memory.

Monocytes

Large agranulocytes ($3\text{rd}$ in abundance) that leave blood vessels to become macrophages and phagocytose pathogens and tissue debris.

Eosinophils

Granulocytes ($4\text{th}$ in abundance) specialized in fighting parasitic infections and involved in allergic reactions.

Basophils

The least abundant granulocytes ($5\text{th}$ in abundance) that secrete histamine and heparin to promote inflammation.

Megakaryocyte

A giant bone marrow cell with a multi-lobed nucleus that extends proplatelet projections into blood vessels to release platelets into circulation.

Hemostasis

The three-step process that stops bleeding from a damaged vessel: vascular spasm, platelet plug formation, and blood coagulation.

Vascular Spasm

The initial rapid constriction of a injured blood vessel to minimize blood loss, facilitated by serotonin released from platelets.

Platelet Plug Formation

The second step of hemostasis where platelets adhere to exposed collagen, release $ADP$ and thromboxane $A_2$, and aggregate into a temporary seal.

Coagulation

The third step of hemostasis where a cascade of reactions converts fibrinogen into a mesh of insoluble fibrin threads to form a stable blood clot.

Plasmin

An active fibrin-dissolving enzyme formed from plasminogen via kallikrein and Factor XII that breaks down clots (thrombolysis/fibrinolysis).

Heparin

A natural anticoagulant produced by the body that interferes with the formation of prothrombin activator to inhibit blood clotting.

Warfarin (Coumadin)

A synthetic anticoagulant medication that acts as a vitamin K antagonist, reducing liver synthesis of blood clotting factors.

Hemophilia

An inherited bleeding disorder caused by a deficiency in a specific clotting factor (e.g., Hemophilia A lacking Factor VIII; Hemophilia B lacking Factor IX).

Embolus

A blood clot or intravascular debris that breaks free from its site of origin and travels in the bloodstream until it blocks a smaller vessel.