Cardiovascular and Hematologic Systems Vocabulary

Cardiopulmonary Resuscitation (CPR)

A lifesaving procedure combining artificial respiration with rhythmic compression of the heart between the sternum and thoracic vertebrae to maintain blood flow during cardiac arrest.

Atria

The two upper receiving chambers of the heart (right and left atria).

Ventricles

The two lower discharging chambers of the heart (right and left ventricles).

Myocardium

The cardiac muscle tissue that composes the wall of each heart chamber.

Endocardium

The smooth inner lining of the heart chambers.

Endocarditis

Inflammation of the endocardium.

Pericardium

A two-layered fibrous sac with a lubricated space between the layers that covers the heart.

Visceral Pericardium (Epicardium)

The inner layer of the pericardium.

Parietal Pericardium

The outer layer of the pericardium.

Systole

The contraction phase (emptying) of the heart during which oxygenated blood is ejected out through the aorta.

Diastole

The relaxation phase (filling) of the heart during which blood flows through the coronary arteries to nourish the heart muscle.

Bicuspid (Mitral) Valve

The left atrioventricular (AV) valve located at the opening of the left atrium into the left ventricle.

Tricuspid Valve

The right atrioventricular (AV) valve located at the opening of the right atrium into the right ventricle.

Pulmonary Semilunar Valve

The semilunar valve located at the beginning of the pulmonary artery.

Aortic Semilunar Valve

The semilunar valve located at the beginning of the aorta.

Lub Sound

The first heart sound, caused by the vibration and closure of the atrioventricular (AV) valves during contraction of the ventricles.

Dup Sound

The second heart sound, caused by the closure of the semilunar valves during relaxation of the ventricles.

Coronary Circulation

The flow of blood through the right and left coronary arteries supplying oxygen and nutrients to the myocardium.

Myocardial Infarction (MI)

A heart attack caused by the blockage of blood flow through the coronary arteries.

Angina Pectoris

Chest pain caused by inadequate oxygen delivery to the heart.

Coronary Bypass Surgery

A surgical procedure where veins from other parts of the body are used to bypass blockages in coronary arteries.

Cardiac Cycle

A single complete heartbeat lasting about $0.8\,\text{second}$, composed of systole and diastole phases.

Stroke Volume

The volume of blood ejected from one ventricle with each heartbeat.

Cardiac Output

The volume of blood pumped by one ventricle per minute, averaging about $5\,\text{L}$ per minute at rest.

Intercalated Disks

Electrical connectors that join all cardiac muscle fibers in a region so they receive electrical impulses and contract nearly simultaneously.

Automaticity

The ability of pacemaker cells to generate an electrical impulse spontaneously.

Excitability

The ability of heart cells to respond to an electrical impulse.

Conductivity

The ability of heart cells to transmit an electrical impulse to adjacent cells.

Sinoatrial (SA) Node

The pacemaker of the heart, located in the wall of the right atrium near the opening of the superior vena cava.

Atrioventricular (AV) Node

A structure located in the right atrium along the lower part of the interatrial septum.

AV Bundle (Bundle of His)

A conduction path located in the septum of the ventricle.

Purkinje Fibers

Specialized conduction fibers located in the walls of the ventricles.

Electrocardiogram (ECG)

A visible tracing of electrical signals traveling through the heart's conduction system.

P Wave

An ECG deflection associated with the depolarization of the atria.

QRS Complex

An ECG deflection associated with the depolarization of the ventricles.

T Wave

An ECG deflection associated with the repolarization of the ventricles.

Arteries

Blood vessels that carry blood away from the heart toward capillaries.

Veins

Blood vessels that carry blood toward the heart and away from capillaries.

Capillaries

Microscopic exchange vessels that carry blood from arterioles to venules.

Tunica Externa

The thin outer layer of blood vessels made of fibrous elastic connective tissue (also called tunica adventitia in veins).

Tunica Media

The middle layer of blood vessels composed of smooth muscle tissue.

Tunica Intima

The inner layer of blood vessels lined by a single layer of squamous epithelial cells.

Systemic Circulation

Blood circulation carrying oxygenated blood throughout the body from the left ventricle through the aorta and back to the right atrium via the venae cavae.

Pulmonary Circulation

Blood circulation carrying deoxygenated blood from the right ventricle through pulmonary arteries to the lungs for gas exchange, returning to the left atrium via pulmonary veins.

Hepatic Portal Circulation

A unique blood route through the liver where the hepatic portal vein exists between two capillary beds to