Anatomy: Chapter 10, Blood

Vocabulary flashcards covering the composition, cellular anatomy, physiology, and homeostatic imbalances of blood.

Hematocrit

The percentage of erythrocytes (red blood cells) in whole blood, normally comprising approximately $45\%$ of total blood volume.

Buffy coat

The thin layer that forms between plasma and erythrocytes in centrifuged blood, making up less than $1\%$ of total volume and containing leukocytes and platelets.

Plasma

The liquid portion of blood comprising $55\%$ of total volume; it is $90\%$ water and distributes heat, nutrients, electrolytes, gases, hormones, wastes, and proteins.

Erythrocytes

Anucleated, biconcave disk-shaped red blood cells that transport oxygen, live approximately $120\text{ days}$, and have a normal count of $4,200,000 - 6,200,000/\text{mL}$.

Hemoglobin

An iron-containing, oxygen-binding pigment that makes up one-third of an erythrocyte and gives blood its red color.

Anemia

A homeostatic imbalance resulting in a decrease in the oxygen-carrying ability of the blood, caused by a lower-than-normal RBC count or deficient/abnormal hemoglobin.

Sickle Cell Anemia

A genetic condition where abnormal hemoglobin causes RBCs to become spiky and sharp, leading them to rupture easily, interfere with oxygen delivery, and cause extreme pain.

Polycythemia

An excessive or abnormal increase in the number of erythrocytes, causing blood to become more viscous, flow sluggishly, and impair circulation.

Neutrophil

A type of leukocyte that phagocytizes small particles.

Eosinophil

A leukocyte that kills parasites and helps control allergic reactions and inflammation.

Basophil

A leukocyte that releases histamine and heparin to trigger responses in the immune system.

Monocyte

A large type of leukocyte that phagocytizes large particles.

Lymphocyte

A leukocyte, encompassing B and T cells, that provides immunity; formed in red bone marrow.

Leukopenia

An abnormally low total white blood cell count, generally indicating the onset of a bacterial or viral infection.

Leukocytosis

A total white blood cell count above the normal range of $5,000 - 10,000/\text{mL}$, generally indicating an active bacterial or viral infection.

Leukemia

A cancer of the bone marrow leading to the rapid overproduction of huge numbers of immature, nonfunctional white blood cells.

Platelets

Anucleated cell fragments derived from megakaryocytes that live for approximately $10\text{ days}$ and are essential for blood clotting.

Megakaryocytes

Large, multinucleated bone marrow cells whose pinched-off cytoplasmic fragments form platelets.

Hemostasis

A localized physiological response meaning 'blood standing still' that acts to stop blood loss from a broken vessel through vascular spasms, platelet plug formation, and coagulation.

Vascular Spasms

The immediate response during hemostasis where a damaged blood vessel constricts to reduce blood loss.

Platelet Plug

A structure formed when platelets become sticky and spiky, adhering to collagen fibers of a broken vessel and attracting more platelets via positive feedback.

Coagulation

The third step of hemostasis in which blood is transformed from a liquid into a gel, producing a fibrin clot.

Thrombus

A persistent blood clot that develops in an unbroken blood vessel, potentially blocking circulation if large enough.

Embolus

A thrombus that breaks free from a vessel wall and floats through the bloodstream, presenting a risk if it lodges in a narrow blood vessel.

Thrombocytopenia

A bleeding disorder caused by an insufficient number of platelets, leading to spontaneous bleeding from small vessels and small purplish blotches on the skin.

Hemophilia

A group of hereditary bleeding disorders resulting from a lack of factors necessary for clotting, leading to prolonged bleeding.

Hematopoiesis

The process of blood cell formation that takes place in red bone marrow, such as in flat bones and the proximal epiphyses of the humerus and femur.

Hemocytoblast

The common stem cell, or 'blood cell former,' in red bone marrow from which all formed elements of blood develop.

Antigen

A substance recognized as foreign by the body that stimulates the immune system to release antibodies against it.

Rh factor

A group of red blood cell membrane antigens (most commonly C, D, and E); an individual whose erythrocytes carry the antigen is considered Rh+.

Fetal Hemoglobin

A specialized form of hemoglobin present before birth that possesses a greater affinity for picking up oxygen than adult hemoglobin.

Jaundice

A condition occurring in newborns when fetal hemoglobin is broken down at a rapid rate and the immature liver cannot excrete the resulting bile pigments fast enough.