Chapter 14: Blood and its Characteristics

Vocabulary-style flashcards covering the components, characteristics, production, and clinical aspects of human blood based on Chapter 14 lecture notes.

Blood

A type of connective tissue suspended in a liquid matrix that transports substances, maintains interstitial fluid stability, and distributes heat.

Formed elements

The solid components of blood that form mostly in red bone marrow, including red blood cells, white blood cells, and platelets.

Hematocrit (HCT)

The percentage of red blood cells (RBCs) in a centrifuged blood sample, also known as packed cell volume (PCV); it typically accounts for $45\%$ of blood.

Plasma

The clear, straw-colored liquid portion of blood that makes up about $55\%$ of blood volume and is consisting of $92\%$ water.

Universal Precautions

Safety measures assumed by healthcare workers where all patients are treated as potential carriers of bloodborne pathogens like HIV and Hepatitis B.

Hematopoiesis

The formation of blood cells which originate in red marrow from hematopoietic stem cells or hemocytoblasts.

Erythrocytes

Red blood cells (RBCs) characterized by a biconcave disc shape and the presence of hemoglobin, but lacking nuclei and mitochondria.

Oxyhemoglobin

A form of hemoglobin that is combined with oxygen ($O_2$).

Deoxyhemoglobin

A form of hemoglobin that is without oxygen ($O_2$).

Erythropoietin (EPO)

A hormone released by the kidneys and liver that stimulates red blood cell production in response to low blood $O_2$ levels.

Anemia

A condition in which the $O_2$-carrying capacity of the blood is reduced due to a deficiency of RBCs or hemoglobin.

Biliverdin and Bilirubin

Bile pigments secreted in bile that result from the decomposition of the heme portion of hemoglobin during RBC destruction.

Granulocytes

A category of white blood cells with granular cytoplasm and short lifespans, including neutrophils, eosinophils, and basophils.

Neutrophils

The most abundant leukocytes ($54-62\%$) that have lobed nuclei and act as strong phagocytes at infection sites.

Eosinophils

Leukocytes ($1-3\%$) that moderate allergic reactions and defend against parasitic worm infestations; they stain deep red in acid stain.

Basophils

Leukocytes representing less than $1\%$ of the total that release histamine for inflammation and heparin to inhibit blood clotting.

Monocytes

The largest white blood cells ($3-9\%$) which leave the bloodstream to become macrophages and phagocytize bacteria and debris.

Lymphocytes

Agranulocytes ($25-33\%$) consisting of T cells, which attack pathogens directly, and B cells, which produce antibodies.

Diapedesis

The process by which white blood cells squeeze between cells of a capillary wall to leave the blood vessel and migrate toward an infection site.

Positive chemotaxis

The attraction of white blood cells toward an infection site by chemicals released by damaged cells.

Leukocytosis

A high white blood cell count exceeding $10,500/\mu L$, often indicating acute infection or vigorous exercise.

Leukopenia

A low white blood cell count below $3,500/\mu L$, associated with conditions like typhoid fever, flu, and AIDS.

Platelets (thrombocytes)

Cellular fragments of megakaryocytes that lack a nucleus and help control blood loss in damaged vessels.

Nonprotein Nitrogenous Substances (NPNs)

Molecules in plasma containing nitrogen that are not proteins, such as urea, uric acid, and creatinine.

Hemostasis

The process of stopping bleeding through vascular spasm, platelet plug formation, and blood coagulation.

Fibrin

An insoluble thread-like protein formed from fibrinogen during blood coagulation that traps blood cells to create a clot.

Serum

The liquid portion of blood that remains after a clot forms, consisting of plasma minus fibrinogen and most clotting factors.

Thrombus

An abnormal blood clot that forms in a blood vessel.

Embolus

A blood clot that breaks loose and moves through the blood vessels.

Agglutination

The clumping of red blood cells that occurs when an antibody in the recipient's plasma reacts with a specific antigen on donor RBCs.

Rh positive

The presence of Antigen D (or other Rh antigens) on the red blood cell membranes.

Erythroblastosis fetalis

A hemolytic disease of the newborn that occurs when maternal anti-Rh antibodies attack the RBCs of an Rh-positive fetus.