General Characteristics and Functions of Blood

Vocabulary flashcards covering the components, functions, volume, hematocrit, viscosity, and sedimentation rate of human blood based on lecture notes.

Blood

The body's only fluid tissue; a red, viscous, and opaque liquid composed of formed elements suspended in plasma.

Erythrocytes (RBCs)

Formed elements that make up more than $99\%$ of the blood cells.

Leukocytes (WBCs)

Cells that make up less than $1\%$ of total blood volume and are responsible for immune defense.

Thrombocytes (Platelets)

Cell fragments that are vital for the blood clotting process.

Isoosmia

The maintenance of constant osmotic pressure in the blood via plasma proteins.

Isoionia

The maintenance of stable ion concentrations (anions and cations) within the blood.

Isohydria

The maintenance of a constant blood pH, typically $7.4 \pm 0.04$, using buffer systems like bicarbonate, phosphates, and hemoglobin.

Hemostasis (Function)

A protective blood mechanism that prevents blood loss through clotting when a vessel is injured.

Normovolemia

The total blood volume in a healthy adult, approximately $7-8\%$ of body weight (about $5.5$ liters for a $70\,kg$ man).

Hypervolemia

A blood volume greater than the physiological normal, occurring during conditions like pregnancy or high fluid intake.

Hypovolemia

A blood volume lower than the physiological normal, occurring after blood loss or dehydration.

Hematocrit (Packed Cell Volume)

The proportion of total blood volume occupied by red blood cells; normal values are $44 \pm 5\%$ for men and $39 \pm 4\%$ for women.

Physiological Polycythemia

A clinical condition where hematocrit increases, often associated with living at high altitudes.

Viscosity (Blood)

A measure of blood's resistance to flow relative to distilled water; whole blood has a relative viscosity of $3.0-3.6$.

Plasma Viscosity

The relative resistance of plasma to flow, ranging from $1.5-2.0$, primarily determined by plasma proteins like fibrinogen.

Fibrinogen (Viscosity)

A plasma protein that, despite making up only $4\%$ of plasma proteins, accounts for over $20\%$ of plasma viscosity due to its large, asymmetrical structure.

Erythrocyte Sedimentation Rate (ESR)

A measure of how far the top of the RBC layer falls in a vertical tube in one hour; normal values are up to $15\,mm/h$ for males and $20\,mm/h$ for females.

Westergren method

The specific laboratory procedure used to measure the Erythrocyte Sedimentation Rate (ESR).

Rouleaux Formation

The stacking of RBCs like coins due to large asymmetrical proteins bridging their negative charges, which results in a smaller surface-area-to-volume ratio and a faster sedimentation rate.