Blood Components & Hemostasis – Lecture Review

13 question-and-answer flashcards covering key blood physiology topics from the lecture notes.

What is the average lifespan of a red blood cell (erythrocyte)?

About 120 days before it is removed by macrophages in the spleen and liver.

How do antigens determine an individual’s blood type?

Blood-group antigens (A, B, Rh, etc.) are glycoproteins on the surface of RBCs; the combination present dictates the ABO/Rh blood type and which antibodies the person naturally produces.

List the three major steps that restore hemostasis after a small vessel injury (e.g., paper cut).

1) Vascular spasm (vessel constriction), 2) Platelet plug formation, 3) Coagulation cascade leading to fibrin clot formation.

Which leukocytes are classified as granulocytes?

Neutrophils, eosinophils, and basophils (contain visible cytoplasmic granules).

Which leukocytes are classified as agranulocytes?

Lymphocytes and monocytes (lack prominent cytoplasmic granules).

State four main functions of blood.

Transportation (gases, nutrients, wastes, hormones), regulation (pH, temperature, fluid volume), protection (hemostasis and immunity), and communication (hormone distribution).

Name the five types of white blood cells and indicate when each is typically most active.

Neutrophils – first responders to bacterial infection; Lymphocytes – viral infections and adaptive immunity; Monocytes/Macrophages – chronic infections, phagocytosis; Eosinophils – parasitic worms, allergies; Basophils – release histamine in allergic and inflammatory reactions.

Define hemoglobin and state its primary role.

A globular protein in RBCs that binds oxygen (via iron in its heme groups) for transport and carries ~20% of blood CO₂ back to the lungs.

What is the role of fibrinogen in the blood?

Soluble plasma protein that is converted by thrombin into insoluble fibrin strands, forming the structural mesh of a blood clot.

Define chemotaxis in the context of leukocyte function.

Directed movement of white blood cells toward higher concentrations of chemical signals released from damaged tissues or pathogens.

Define diapedesis.

Process by which leukocytes squeeze through capillary walls to leave the bloodstream and enter tissues at sites of inflammation or infection.

Differentiate leukopenia, leukemia, and lymphoma.

Leukopenia – abnormally low WBC count; Leukemia – cancer of blood-forming tissues causing excessive, abnormal WBCs in blood; Lymphoma – cancer of lymphoid tissues producing tumor masses of lymphocytes.

State the primary functions of albumin, globulins, and fibrinogen.

Albumin – maintains osmotic pressure and transports small molecules; Globulins – include antibodies (immunoglobulins) and transport proteins; Fibrinogen – precursor to fibrin, essential for clotting.