The Blood - Chapter 19

Flashcards covering key vocabulary and concepts related to blood and its components.

Blood

Functions include transport of nutrients, wastes, and hormones; regulation of pH and temperature; and protection against infection and blood loss.

Constituents of Blood

Blood is approximately 5 liters of connective tissue composed of cells/formed elements (45%) and blood plasma (55%).

Blood Plasma

A salt-water-and-protein solution that is viscous, denser than water, slightly warmer than core body temperature (38°C), and slightly alkaline (pH 7.35-7.45).

Plasma

Approximately 92% water, with dissolved solutes consisting mostly of proteins, electrolytes, and gases.

Albumin

A major plasma protein responsible for osmotic pressure, viscosity, and carrier functions for hydrophobic molecules; synthesized in the liver.

Globulins

Plasma proteins that act as carriers for some hydrophobic molecules and contribute to immunity.

Fibrinogen

A clotting protein in plasma important in hemostasis.

Hemopoiesis (Hematopoiesis)

The formation of formed elements (red blood cells, white blood cells, and platelets) in red bone marrow.

Red Blood Cells (RBCs or Erythrocytes)

Form the bulk of the formed elements in blood, specialized for oxygen transport, and recycled in the spleen and liver after approximately 120 days.

Hemoglobin (Hgb)

A protein molecule adapted to carry O2 (and CO2), binds oxygen best at high pH, and unbinds oxygen at low pH.

Erythropoiesis

Production of RBCs, where hypoxia stimulates the kidneys to release erythropoietin (EPO) to speed up maturation and release of immature red cells.

Erythropoietin (EPO)

A hormone secreted by kidney cells when blood oxygen is low, targeting cells in red bone marrow to promote increased numbers of mature red blood cells.

Leukocytes

White blood cells (WBCs) with nuclei and organelles, present in 5-10 x 10^3/mm^3, and include five different types with varying functions.

Granulocytes

WBCs that contain granules when stained, including Neutrophils, Eosinophils, and Basophils.

Neutrophil

The most numerous WBC in normal blood (60-70%), functions to phagocytize bacteria.

Eosinophil

A WBC that responds to multicellular parasites and allergens.

Basophil

A WBC involved in the inflammatory response.

Agranulocytes

include monocytes and lymphocytes

Monocytes

Major group of phagocytic cells common in the peripheral tissues.

Lymphocytes

WBCs that respond to very specific foreign antigens.

Megakaryocytes

Huge cells in red bone marrow that splinter into 2000 to 3000 fragments, each fragment becoming a platelet/thrombocyte.

Platelets/Thrombocytes

More numerous than WBCs (150-400 x 10^3/mm^3), with a short life span (5 to 9 days), small mass, no organelles, and involved in hemostasis.

Hemostasis

A sequence of responses that stops bleeding, must be quick and localized; involves vascular spasm, platelet plug formation, and fibrin clot formation.

Vascular Spasm

The constriction of damaged blood vessels.

Platelet Plug Formation

Platelets adhere to damaged endothelium to form a plug.

Fibrin Clot Formation

Activation of clotting proteins in the blood leads to the formation of insoluble fibrin.

Thrombosis

The forming of a thrombus, which is a clot in an unbroken blood vessel.

Embolus

A blood clot, air bubble, piece of fat, or other debris transported by the bloodstream.

Blood Groups

Red cells have surface proteins that act as antigens; the immune system produces antibodies to bind and attack nonself antigens; the A and B antigens on RBCs are significant.

Rh Incompatibility

Rh- individuals will produce anti-Rh antibodies after exposure to the Rh antigen; a problem primarily in pregnancy where an Rh+ fetus can sensitize an Rh- mother.