Unit 2: Cardiovascular System - Blood & Heart

Vocabulary review flashcards covering blood components, formed elements, hematopoiesis, hemostasis, heart anatomy, cardiac cycle, and cardiac electrophysiology from Chapters 19 and 20.

Hematocrit

The percentage of erythrocyte (RBC) volume compared to total blood volume.

Albumin

The most abundant plasma protein ($58\%$), responsible for maintaining osmotic pressure and serving as a carrier protein.

Globulins

Plasma proteins making up $38\%$ of total plasma proteins that function in transport and immune defense as antibodies.

Fibrinogen

A plasma protein ($4\%$ of plasma proteins) that functions as a key clotting factor.

Serum

Blood plasma from which clotting proteins have been removed.

Erythrocytes

Biconcave, anucleated formed elements lacking DNA that make up $99.9\%$ of formed elements, survive for approximately $120$ days, and transport $O_2$ while helping regulate pH.

Hemoglobin

A respiratory pigment composed of $4$ protein subunits ($2$ alpha, $2$ beta) and iron, capable of binding up to $4$ molecules of $O_2$.

Carbaminohemoglobin

Hemoglobin that is bound to carbon dioxide ($CO_2$).

Carboxyhemoglobin

Hemoglobin bound to toxic carbon monoxide ($\text{CO}$).

Bilirubin

A breakdown product of heme from broken-down RBCs that is sent to the liver for excretion in bile; its accumulation causes jaundice.

Diapedesis

The ability of leukocytes (WBCs) to squeeze through blood vessel walls into surrounding tissues.

Chemotaxis

The directed movement of leukocytes toward chemical signals released at sites of infection or tissue damage.

Neutrophils

The most abundant granulocytes ($55\text{--}70\%$ of WBCs) that act as first responders against infection through phagocytosis.

Eosinophils

Granulocytes ($1\text{--}4\%$ of WBCs) specialized in defending against parasitic infections and modulating inflammatory reactions.

Basophils

Granulocytes ($0.5\text{--}1\%$ of WBCs) involved in allergic and immune responses that release histamine and heparin.

Lymphocytes

Agranulocytes ($20\text{--}40\%$ of WBCs) mediating adaptive immunity, consisting of antibody-producing B cells and cell-mediated defense T cells.

Monocytes

The largest agranulocytes ($2\text{--}8\%$ of WBCs) that migrate into tissues to develop into macrophages and phagocytize cellular debris.

Platelets (Thrombocytes)

Cell fragments shed by megakaryocytes that circulate for $9\text{--}12$ days and participate in blood clotting and vessel repair.

Erythropoiesis

The production of red blood cells in red bone marrow, stimulated by erythropoietin (EPO) produced by the kidneys in response to low $O_2$ levels.

Rh Factor

An erythrocyte surface antigen; presence designates an individual as positive ($Rh^+$), and maternal-fetal incompatibility can cause hemolytic disease of the newborn, preventable with RhoGAM.

Hemostasis

The multi-step process that stops bleeding, progressing through the vascular phase, platelet phase, and coagulation phase.

Fibrinolysis

The physiological breakdown and removal of a blood clot carried out by the enzyme plasmin.

Thrombus

A stationary blood clot that forms inappropriately within an intact blood vessel.

Embolus

A blood clot or detached mass that travels freely through the bloodstream.

Cardiac Tamponade

A life-threatening condition in which fluid accumulates in the pericardial cavity, compressing the heart and restricting its ability to pump.

Myocardium

The thick, contractile middle layer of the heart wall composed of cardiac muscle, thickest in the left ventricle.

Endocardium

The smooth internal endothelial lining of the heart chambers that is continuous with the inner lining of blood vessels.

Chordae Tendineae

Tendinous cords anchored by papillary muscles that prevent the atrioventricular (AV) valve cusps from everting into the atria during ventricular contraction.

Stroke Volume (SV)

The volume of blood pumped out by a ventricle during a single heartbeat.

Cardiac Output

The total volume of blood pumped by the heart per minute, calculated as $\text{Cardiac output} = \text{HR} \times \text{SV}$.

Functional Syncytium

A mass of interconnected cardiac muscle cells that contract together as a coordinated, unified unit due to autoconduction across intercalated discs.

Sinoatrial (SA) Node

The primary physiological pacemaker of the heart, located in the right atrium, which spontaneously initiates electrical impulses.

Atrioventricular (AV) Node

A specialized group of autorhythmic cells that delays the cardiac electrical impulse to ensure complete atrial contraction before ventricular systole.

P Wave

The ECG deflection that represents atrial depolarization.

QRS Complex

The ECG deflection wave complex that represents ventricular depolarization.

T Wave

The ECG wave indicating ventricular repolarization.

Bradycardia

A resting heart rate slower than $60\,\text{bpm}$.

Tachycardia

An abnormally rapid resting heart rate exceeding $100\,\text{bpm}$.

Fibrillation

Rapid, uncoordinated, and chaotic contractions of cardiac muscle fibers, presenting extreme danger when occurring in the ventricles.

Heart Block

An arrhythmia characterized by impaired electrical conduction through the atrioventricular (AV) node.