Blood Physiology and Hematology Practice Flashcards

Vocabulary practice flashcards generated from the blood physiology and hematology lecture transcript.

Blood

A fluid connective tissue forming part of the extracellular fluid within the cardiovascular system, comprising cellular constituents suspended in an acellular yellowish plasma and accounting for approximately $8\,\%$ of adult body weight.

Albumin/Globulin (A/G) Ratio

The ratio between the plasma levels of albumin and globulin, which acts as an important indicator of liver or kidney diseases and has a normal value of $2.1$.

Starling's Hypothesis

The principle stating that net filtration through a capillary membrane is proportional to the hydrostatic pressure difference across the membrane minus the oncotic pressure difference.

Red Blood Cells (Erythrocytes)

Anucleate, biconcave discs lacking mitochondria and organelles, measuring $7.2\,\mu\text{m}$ in diameter and $2.2\,\mu\text{m}$ in thickness, whose main function is to transport hemoglobin carrying oxygen and carbon dioxide.

Rouleaux Formation

The phenomenon in which red blood cells pile up one above the other and settle at the bottom of a tube when an anticoagulated blood sample is left standing.

Packed Cell Volume (Haematocrit)

The proportion of total blood volume occupied by red blood cells (normally $45\,\%$) after anticoagulated blood is centrifuged.

Erythrocytosis

An increase in the number of red blood cells in circulation.

Polycythemia Vera

A pathological condition caused by genetic aberration in hemocytoblastic cells, resulting in abnormally high RBC count and PCV, which increases blood viscosity up to 10 times that of water.

Haemopoiesis

The process of forming new blood cellular components, producing approximately $10^{11}$ to $10^{12}$ new blood cells daily in adult humans to maintain steady state levels.

Haemopoietic Stem Cell Lineage

The differentiation pathway originating from pluripotent stem cells, branching into lymphoid stem cells and colony-forming blastocytes (CFU-E, CFU-M, CFU-GM) to form mature blood cells.

Erythropoietin

A glycoprotein hormone (MW $33,000$) secreted mainly by the kidneys ($90\,\%$) and liver ($10\,\%$) in response to tissue hypoxia to stimulate erythropoiesis in red bone marrow.

Proerythroblast (Pronormoblast)

The first recognizable erythrocyte precursor in bone marrow, measuring $20\,\mu\text{m}$ in diameter, containing a large nucleus and basophilic cytoplasm, but lacking hemoglobin.

Reticulocyte

An immature, basophilic red blood cell that is larger than a mature RBC and contains remnants of a reticular network, Golgi apparatus, and mitochondria, normally constituting $2\,\%$ to $6\,\%$ of circulating red blood cells.

Haemoglobin

A chromoprotein (MW $68,000$) forming $95\,\%$ of dry weight ($30\,\%$ to $34\,\%$ wet weight) of RBCs, composed of two $\alpha$ and two $\beta$ globin chains, each bound to an iron-containing heme group.

Oxygen Dissociation Curve

A sigmoidal graph showing the relationship between oxygen saturation and partial pressure of oxygen ($\text{PO}_2$), demonstrating Hb affinity for oxygen relative to myoglobin.

HbS

An abnormal hemoglobin variant associated with sickle cell anaemia, caused by a gene mutation where valine replaces glutamine in the 6th position of the $\beta$-chain of globin.

Normocytic Normochromic Anaemia

A classification of anaemia where the size and hemoglobin content of individual red blood cells are normal, but the total number of RBCs in circulation is reduced.

Aplastic Anaemia

Anaemia caused by red bone marrow damage or replacement by fatty tissues, associated with radiation exposure, bacterial toxins, HIV, hepatitis, tuberculosis, or chemical agents like benzene.

Neutrophils

Polymorphonuclear granulocytes measuring $10\,\mu\text{m}$ to $12\,\mu\text{m}$ with 2 to 5 nuclear lobes and violet-staining fine granules containing defensins ($\alpha$ and $\beta$), NADPH oxidase, catalase, and myeloperoxidase.

Eosinophils

Leukocytes measuring $10\,\mu\text{m}$ to $14\,\mu\text{m}$ with a spectacle-shaped bilobed nucleus and coarse granules that stain pink/red with eosin, functioning in allergic defense and detoxification.

Basophils

Granulocytes measuring $8\,\mu\text{m}$ to $10\,\mu\text{m}$ with coarse granules staining purple-blue with methylene blue, accounting for $0\,\%$ to $1\,\%$ of circulating WBCs and secreting IgE, heparin, histamine, serotonin, and IL-4.

Monocytes

The largest circulating leukocytes ($14\,\mu\text{m}$ to $18\,\mu\text{m}$ in diameter) with clear or finely granular cytoplasm, acting as motile phagocytes and precursors to tissue macrophages.

Innate Immunity

Inborn, non-specific natural defense mechanisms present from birth, including epithelial skin barriers, stomach acid, lysozyme, and phagocytic leukocytes.

Acquired Immunity

Adaptive immunity developing specific resistance against pathogens through humoral immunity (mediated by B-lymphocytes and antibodies) and cellular immunity (mediated by T-lymphocytes).

Natural Killer (NK) Cells

Non-T, non-B large granular lymphocytes containing hydrolytic granules that recognize and destroy tumor cells, infected cells, or foreign organisms without prior sensitization.

Complement System

A system of approximately 20 plasma proteins (primarily C1 through C9) that undergo sequential enzymatic cascade activation to mediate opsonization, cell lysis, agglutination, virus neutralization, and chemotaxis.

Platelets (Thrombocytes)

Small, non-nucleated biconvex discs ($2\,\mu\text{m}$ to $4\,\mu\text{m}$ in diameter) derived from bone marrow megakaryocytes with a normal circulating lifespan of 8 to 10 days and concentration of $150 \times 10^9/\text{L}$ to $400 \times 10^9/\text{L}$.

Haemostasis

The complex physiological process that arrests bleeding from injured blood vessels through four interlinked steps: vasoconstriction, platelet plug formation, blood coagulation, and fibrinolysis.

Coagulation Cascade Pathways

The series of enzymatic reactions divided into intrinsic and extrinsic pathways that lead to Factor X activation, converting prothrombin to thrombin and soluble fibrinogen into a crosslinked fibrin clot.

Fibrinolysis

The enzymatic degradation of insoluble fibrin into fibrin degradation products (FDP) by plasmin to clear clots and maintain blood vessel patency.

Landsteiner's Law

The rule of transfusion reaction stating that if a specific agglutinogen antigen is present on an individual's RBC membrane, the corresponding agglutinin antibody must be absent from their serum.

ABO Blood Group System

The human blood classification scheme based on the presence or absence of A and B oligosaccharide surface antigens on red blood cells and corresponding anti-A or anti-B antibodies in plasma.

Erythroblastosis Fetalis

A hemolytic disease of the newborn occurring when an Rh-negative mother is sensitized by an Rh-positive fetus, causing maternal anti-D antibodies to cross the placenta and destroy fetal red blood cells in subsequent pregnancies.