Heart Chambers, Circulation, Valves & Cardiac Muscle Vocabulary

Vocabulary flashcards summarizing key anatomical and physiological terms related to heart chambers, circulation pathways, valves, and unique features of cardiac muscle.

Pulmonary Circulation

Circuit that carries deoxygenated blood from the right heart to the lungs and returns oxygenated blood to the left heart.

Systemic Circulation

Circuit that delivers oxygen-rich blood from the left heart to the body and returns oxygen-poor blood to the right heart.

Right Atrium

Receiving chamber for systemic, deoxygenated blood.

Left Atrium

Receiving chamber for oxygenated blood returning from the lungs.

Right Ventricle

Low-pressure pump that sends blood to the pulmonary arteries and lungs (≈40 mmHg).

Left Ventricle

High-pressure pump that propels blood into the aorta and systemic circulation (≈120 mmHg at rest).

Aorta

Largest artery; begins systemic circulation and gives rise to the coronary arteries.

Coronary Arteries

First branches of the aorta that supply the myocardium; fill mainly during diastole.

Septum

Thick muscular wall separating right and left sides of the heart, preventing blood mixing.

Atrioventricular (AV) Valves

One-way valves between atria and ventricles that prevent backflow into the atria.

Tricuspid Valve

Right AV valve with three cusps between right atrium and right ventricle.

Bicuspid (Mitral) Valve

Left AV valve with two cusps between left atrium and left ventricle.

Semilunar Valves

Pocket-shaped valves between ventricles and great arteries (pulmonary and aortic valves).

Pulmonary Valve

Semilunar valve separating right ventricle from pulmonary trunk.

Aortic Valve

Semilunar valve separating left ventricle from aorta.

Chordae Tendineae

Tendon-like cords anchoring AV valve cusps to papillary muscles, preventing prolapse.

Papillary Muscles

Ventricular projections that contract to tighten chordae tendineae during systole.

Valvular Stenosis

Pathological narrowing and stiffening of a heart valve, producing turbulent forward flow.

Valvular Regurgitation

Failure of a valve to close completely, allowing backward blood flow.

Heart Murmur

Audible sound produced by turbulent blood flow, often due to valvular defects.

Intercalated Discs

Specialized junctions linking cardiac muscle cells end-to-end for mechanical and electrical coupling.

Desmosomes

Strong cell junctions in intercalated discs that mechanically bind cardiomyocytes together.

Gap Junctions

Low-resistance channels in intercalated discs permitting ion flow and rapid electrical spread.

Functional Syncytium

Property whereby interconnected cardiac cells contract as a single coordinated unit.

Sarcomere

Basic contractile unit of striated muscle; arrangement less orderly in cardiac than skeletal muscle.

T-Tubules (Cardiac)

Large, branched invaginations of the sarcolemma that aid excitation-contraction coupling.

Sarcoplasmic Reticulum (Cardiac)

Less extensive Ca²⁺ store; about 10 % of trigger calcium enters from extracellular fluid.

Mitochondrial Density (Cardiac)

Mitochondria occupy up to one-third of cardiomyocyte volume, supporting continuous aerobic metabolism.

Oxygen Extraction by Heart

Cardiac muscle removes 70-80 % of oxygen from coronary blood at rest, leaving little reserve.

Preferred Fuels of Cardiac Muscle

Primarily fatty acids; also uses glucose and oxidizes lactate during exercise for ATP.