Advanced Anatomy and Physiology: Circulatory System

Vocabulary flashcards based on lecture notes covering the cardiovascular system, including heart chambers, cardiac cycle, conduction, blood vessels, formed elements, and blood typing.

Myocardium

The muscular middle layer of the heart wall composed of cardiac muscle responsible for contracting to pump blood.

Endocardium

The innermost lining layer of the heart chambers.

Epicardium

The outermost tissue layer of the heart wall.

Pericardium

An outer double-walled sac surrounding the heart that prevents friction during contraction.

Interatrial septum

A thin wall of tissue separating the right atrium and the left atrium.

Interventricular septum

A muscular and membranous wall dividing the right ventricle and the left ventricle.

Tricuspid valve

The right atrioventricular valve situated between the right atrium and the right ventricle.

Pulmonary valve

The right semilunar valve situated between the right ventricle and the pulmonary artery.

Mitral valve

The left atrioventricular valve, also called the bicuspid valve, located between the left atrium and the left ventricle.

Aortic valve

The left semilunar valve located between the left ventricle and the aorta.

Sinoatrial (SA) node

The natural pacemaker of the heart located in the upper chamber that generates electrical signals to initiate each heartbeat.

Atrioventricular (AV) node

A structure in the heart's conduction system that conducts electrical impulses from the atria down to the ventricles.

Purkinje fibers

Specialized conductive fibers that distribute electrical impulses throughout the ventricles, causing them to contract.

Systole

The contraction phase of the cardiac cycle in which the ventricles pump blood into the pulmonary artery and aorta.

Diastole

The relaxation phase of the cardiac cycle during which the ventricles fill with blood from the atria.

Bradycardia

A resting heart rate that is below $60\,\text{beats per minute}$.

Tachycardia

A resting heart rate that is above $100\,\text{beats per minute}$.

Tunica adventitia

The thick outer connective tissue layer of a blood vessel that protects against rupture caused by increased pressure.

Tunica media

The middle layer of a blood vessel composed of smooth muscle and elastic fibers that helps maintain normal blood pressure.

Tunica intima

The smooth inner endothelial cell lining of a blood vessel that prevents abnormal blood clotting.

Plasma

The liquid component of unclotted whole blood, accounting for approximately $55\%$ of blood volume ($2.8\,L$), which contains fibrinogen and clotting factors.

Serum

The liquid portion of blood left behind after clotting, which lacks fibrinogen and clotting factors.

Erythrocytes

Red blood cells filled with hemoglobin that transport oxygen and carbon dioxide, having a average lifespan of $120\,\text{days}$.

Neutrophils

The most abundant white blood cells ($45\text{--}70\%$) that serve as first responders to bacterial or viral infections.

Eosinophils

Leukocytes ($0\text{--}5\%$) involved in allergic responses and defense against parasitic infections.

Basophils

Leukocytes ($0\text{--}1\%$) that release histamine during inflammation to dilate blood vessels and play a role in asthma.

Lymphocytes

Leukocytes ($20\text{--}40\%$) consisting of T cells (which destroy foreign cells) and B cells (which produce antibodies).

Monocytes

The largest leukocytes ($4\text{--}10\%$), acting as phagocytes to engulf and clean up cellular debris and dead cells.

Thrombocytes

Platelets with a lifespan of $9\text{--}12\,\text{days}$ that mediate blood clotting, form temporary vascular patches, and contract after clot formation.

Antigen

A foreign substance that triggers an immune response and stimulates the formation of specific antibodies.

Antibody

A protective protein produced by B lymphocytes in response to an antigen to neutralize or destroy it.

Rhogam

A medication given to Rh-negative mothers around $28\,\text{weeks}$ of pregnancy and within $72\,\text{hours}$ post-delivery to prevent immune sensitization against an Rh-positive fetus.

Human leukocyte antigen (HLA)

A group of surface cell proteins involved in self/non-self immune recognition, tested to evaluate tissue compatibility in organ and bone marrow transplants.