Haematology & Immunity

Vocabulary flashcards covering key terms and concepts from the hematology lecture notes, including blood composition, RBC structure and function, erythropoiesis, plasma proteins, and common disorders.

Blood

The fluid connective tissue consisting of plasma and formed elements (RBCs, WBCs, platelets) that transports gases, nutrients, wastes, and hormones and participates in immunity and hemostasis.

Plasma

The clear yellowish fluid portion of blood that contains water, electrolytes, nutrients, hormones, waste products, and plasma proteins.

Formed elements

The cellular components of blood—red blood cells (RBCs), white blood cells (WBCs), and platelets.

Erythrocyte (RBC)

Red blood cell; a biconcave, anucleate cell that carries oxygen via hemoglobin and relies on glycolysis for energy.

Leukocyte (WBC)

White blood cell; part of the immune system with several subtypes that defend the body against pathogens.

Platelet (Thrombocyte)

Cell fragment essential for hemostasis and clot formation.

Hematocrit

The percentage of blood volume occupied by red blood cells.

Biconcave disc

Shape of mature erythrocytes that increases surface area for gas exchange.

RBC diameter

Approximately 8 micrometers (µm) in humans.

RBC volume

Approx. 90 femtoliters (fL) per cell.

RBC life span

About 120 days in circulation before senescence and removal.

No nucleus in mature RBCs

Mature erythrocytes lack a nucleus and most organelles.

Hemoglobin (Hb)

Iron-containing protein in RBCs that binds O2 and CO2; composed of heme groups and globin chains.

Heme

Iron-containing porphyrin ring within Hb that binds oxygen.

Globin

Protein part of Hb; in adults consists of alpha and beta chains.

Iron (Fe) in Hb

Central metal atom in heme that binds oxygen; iron is recycled and stored.

Oxygen-carrying capacity

The ability of blood to transport oxygen, depending on Hb amount and RBC count.

Carbonic anhydrase

RBC enzyme that rapidly converts CO2 and water to bicarbonate and protons (facilitating CO2 transport).

Reticulocyte

An immature RBC released from bone marrow; matures into an erythrocyte in about 1–2 days (~1% of circulating RBCs).

Erythropoiesis

Production of red blood cells in the bone marrow.

Erythropoietin (EPO)

Hormone produced mainly by the kidneys that stimulates erythropoiesis in the bone marrow.

Iron

Iron in heme; essential for Hb synthesis and oxygen transport; stored as ferritin and transported by transferrin.

Ferritin

Protein that stores iron in tissues.

Transferrin

Plasma protein that transports iron in the blood.

Bilirubin

Yellow pigment produced from heme degradation; excreted in bile; elevated levels can cause jaundice.

Heme oxygenase

Enzyme that degrades heme to biliverdin, releasing iron.

Agranulocytosis

Very low levels of granulocytes (a type of WBC); risk of infection.

Anemia

Condition characterized by a reduced number of RBCs or reduced Hb concentration, resulting in decreased oxygen-carrying capacity.

Iron-deficiency anemia

Anemia caused by insufficient iron for Hb synthesis.

Pernicious anemia

Megaloblastic anemia due to impaired vitamin B12 absorption, often from gastric mucosa damage.

Megaloblastic anemia

Anemia with enlarged, immature RBC precursors due to faulty DNA synthesis.

Aplastic anemia

Reduced bone marrow function leading to decreased production of RBCs, WBCs, and platelets.

Hemolytic anemia

Anemia caused by premature destruction of RBCs; can be genetic (e.g., HbS, thalassemia) or acquired.

Sickle cell anemia

Hemolytic anemia caused by HbS; RBCs become rigid and sickle-shaped under low oxygen.

Thalassemia

Inherited Hb synthesis disorder causing small, fragile RBCs and anemia.

Plasma proteins

Proteins dissolved in plasma; three major types: albumin, globulins, and fibrinogen.

Albumin

Major plasma protein that maintains osmotic (colloid) pressure and transports substances.

Globulin

Plasma proteins including antibodies; participate in transport and immune defense.

Fibrinogen

Plasma protein essential for blood coagulation; converted to fibrin during clot formation.

Coagulation cascade

Sequence of proteolytic reactions leading to the formation of a fibrin clot.

Vascular spasm

Immediate vasoconstriction of a damaged blood vessel to reduce blood loss.

Platelet plug

Temporary aggregation of platelets to seal small vessel injuries before coagulation.

Fibrinolysis

Process of clot breakdown and dissolution after healing.

Blood groups

Classification of blood based on surface antigens (e.g., ABO) affecting transfusion compatibility.

Transfusion reactions

Adverse immune responses to donor blood due to incompatibility.

RBC life cycle

Development from hematopoietic stem cell to mature erythrocyte and eventual senescence.