Hemostasis and Blood Groups Vocabulary

A comprehensive set of vocabulary flashcards covering key terms related to hemostasis, coagulation pathways, anticoagulants, and blood group compatibility for exam preparation.

Hemostasis

The overall process that stops bleeding, consisting of vascular spasm, platelet plug formation, and coagulation.

Vascular Spasm

Reflex contraction of smooth muscle in a damaged blood vessel that reduces blood flow and loss.

Platelet Plug Formation

The gathering and adhesion of platelets at a vessel injury site to form a temporary seal.

Coagulation

Conversion of blood from a liquid to a gel by a cascade of clotting factors, producing a fibrin mesh.

Fibrin

Insoluble protein threads that weave through a clot, trapping cells and strengthening the plug.

Clotting Cascade

A sequential activation of clotting factors in which each enzyme activates the next, ending with fibrin formation.

Extrinsic Pathway

Rapid clotting pathway triggered by tissue factor (thromboplastin) released from damaged tissues.

Intrinsic Pathway

Slower clotting pathway initiated when blood contacts exposed collagen or damaged endothelium.

Common Pathway

Final stage of coagulation where prothrombinase converts prothrombin to thrombin, then fibrinogen to fibrin.

Prothrombinase

Enzyme complex that catalyzes the conversion of prothrombin into thrombin.

Prothrombin (Factor II)

Plasma protein produced by the liver that is converted to thrombin during clotting.

Thrombin

Active enzyme that converts fibrinogen to fibrin and amplifies clotting via positive feedback.

Fibrinogen

Soluble plasma protein transformed into insoluble fibrin threads by thrombin.

Platelet Adhesion

Initial sticking of platelets to exposed collagen in a damaged vessel wall.

Platelet Release Reaction

Process in which activated platelets secrete chemicals (e.g., ADP, thromboxane A2) that recruit more platelets.

Platelet Aggregation

Accumulation of additional platelets that reinforces and enlarges the platelet plug.

Positive Feedback in Clotting

Mechanism by which thrombin accelerates formation of more prothrombinase and further platelet activation.

Tissue Factor (Thromboplastin)

Lipoprotein released by damaged tissues that initiates the extrinsic pathway.

Calcium Ions (Ca²⁺)

Essential cofactor required at multiple steps in both intrinsic and extrinsic coagulation pathways.

Clot Retraction

Tightening of the fibrin clot as platelets pull on threads, drawing wound edges together.

Factor XIII (Fibrin-Stabilizing Factor)

Enzyme activated by thrombin that cross-links fibrin strands, stabilizing the clot.

Vitamin K

Fat-soluble vitamin needed by the liver to synthesize clotting factors II, VII, IX, and X.

Anticoagulant

Substance that prevents or suppresses blood clot formation.

Heparin

Fast-acting anticoagulant administered clinically; enhances antithrombin III activity.

Warfarin (Coumadin)

Oral anticoagulant that antagonizes vitamin K, slowing production of clotting factors.

Citrate Phosphate Dextrose (CPD)

Additive in stored blood that chelates Ca²⁺ to prevent clotting.

Thrombolytic Agent

Drug that dissolves existing clots by activating plasminogen to plasmin.

Tissue Plasminogen Activator (t-PA)

Naturally occurring thrombolytic protein used therapeutically to break down clots.

Streptokinase

Bacterial-derived thrombolytic drug that activates plasminogen to dissolve clots.

Thrombus

A stationary clot that forms in an unbroken blood vessel.

Embolism

A traveling clot, air bubble, or fat droplet that can lodge and block a vessel.

Pulmonary Embolus

An embolus that becomes lodged in the pulmonary arteries of the lungs.

Hemophilia

Inherited deficiency of clotting factors causing excessive bleeding after minor injury.

Hemophilia A

Most common form; X-linked absence of clotting factor VIII.

Hemophilia B

X-linked disorder due to lack of clotting factor IX.

Hemophilia C

Deficiency of factor XI; affects both sexes and is usually milder.

Blood Group

Classification based on specific antigens (agglutinogens) on red blood cell surfaces.

Agglutinogen

Antigen on red blood cells that can trigger agglutination if mismatched.

Agglutinin

Antibody in plasma that reacts with specific agglutinogens not present on one’s own RBCs.

Agglutination

Clumping of red blood cells when antibodies bind to incompatible antigens.

Hemolysis

Rupture of red blood cells with release of hemoglobin into plasma.

ABO Blood Group System

Major blood typing system determined by the presence of A and/or B antigens on RBCs.

Rh Blood Group System

Blood typing system based on the presence (Rh⁺) or absence (Rh⁻) of the D antigen.

Universal Donor (O⁻)

Blood type lacking A, B, and Rh antigens; can donate to any recipient.

Universal Recipient (AB⁺)

Blood type that lacks anti-A, anti-B, and anti-Rh antibodies; can receive any compatible blood.

Hemolytic Disease of the Newborn (HDN)

Condition where maternal anti-Rh antibodies destroy Rh⁺ fetal RBCs, causing fetal anemia.

RhoGam

Anti-Rh immunoglobulin given to Rh⁻ mothers to prevent antibody formation against Rh⁺ fetal cells.

Blood Typing

Laboratory determination of ABO and Rh antigens on a person’s red blood cells.

Cross-matching

Testing donor and recipient blood together to ensure compatibility before transfusion.

Transfusion Reaction

Adverse event where incompatibility causes agglutination and hemolysis of transfused red cells.