Overview of Heart Anatomy and Cardiac Conduction System

Right Atrium

Receives deoxygenated blood from the body via the superior and inferior vena cava.

Right Ventricle

Pumps deoxygenated blood to the lungs through the pulmonary artery.

Left Atrium

Receives oxygenated blood from the lungs via the pulmonary veins.

Left Ventricle

Pumps oxygenated blood to the body through the aorta; thickest chamber.

Tricuspid Valve

Valve between the right atrium and right ventricle; prevents backflow.

Pulmonary Valve

Valve between the right ventricle and pulmonary artery.

Bicuspid (Mitral) Valve

Valve between the left atrium and left ventricle; prevents backflow.

Aortic Valve

Valve between the left ventricle and aorta.

Endocardium

Inner lining of the heart chambers; smooth to reduce friction.

Myocardium

Thick middle muscular layer of the heart wall; responsible for contractions.

Epicardium

Outer layer of the heart wall; also called the visceral layer of the pericardium.

Superior Vena Cava

Brings deoxygenated blood from the upper body to the right atrium.

Inferior Vena Cava

Brings deoxygenated blood from the lower body to the right atrium.

Pulmonary Arteries

Carry deoxygenated blood from the right ventricle to the lungs.

Pulmonary Veins

Bring oxygenated blood from the lungs to the left atrium.

Aorta

Largest artery; carries oxygenated blood from the left ventricle to the body.

Septum

Muscular wall dividing the left and right sides of the heart.

Chordae Tendineae

"Heart strings" that anchor valve flaps to papillary muscles.

Papillary Muscles

Muscles in the ventricles that pull on chordae tendineae to prevent valve prolapse.

Pericardium

Double-layered sac around the heart; provides protection and lubrication.

Apex

Pointed lower end of the heart, directed toward the left hip.

Base

Top of the heart where major blood vessels attach.

Sinoatrial (SA) Node

Natural pacemaker of the heart; located in the right atrium; initiates heartbeat.

Atrioventricular (AV) Node

Receives signal from SA node and delays it slightly before passing to the ventricles.

Bundle of His

Pathway of electrical fibers from the AV node down the septum to the ventricles.

Purkinje Fibers

Specialized fibers that spread the electrical impulse through the ventricles, causing contraction.