Heart External Anatomy Overview

Overview

This lecture covers the external anatomy of the heart, focusing on its chambers, major blood vessels, and the coronary circulation system.

The heart has four chambers: right atrium, left atrium, right ventricle, and left ventricle.
Atria are the upper chambers that collect blood; ventricles are larger lower chambers that eject blood.
"Auricles" are ear-like flaps on each atrium.
Grooves on the heart's surface are called sulci; the atrioventricular sulcus is between atria and ventricles, and the interventricular sulcus is between ventricles.
The heart appears twisted so the right side is more anterior and the left more posterior.

The aorta (ascending, arch, descending) carries oxygen-rich blood from the left ventricle to the body.
Three branches from the aorta arch: brachiocephalic trunk, left common carotid artery, and left subclavian artery.
The brachiocephalic trunk splits into the right subclavian artery and right common carotid artery.
The pulmonary trunk carries oxygen-poor blood from the right ventricle to the lungs via the left and right pulmonary arteries.
Pulmonary veins (from both lungs) return oxygen-rich blood to the left atrium.
Superior vena cava returns blood from above the heart, and inferior vena cava returns blood from below the heart, both to the right atrium.

Left and right coronary arteries arise from the base of the aorta and supply heart muscle with oxygen-rich blood.
The left coronary artery branches into the anterior interventricular artery (in the anterior interventricular sulcus) and the circumflex artery.
The right coronary artery travels in the right atrioventricular sulcus and gives rise to the posterior interventricular artery.
The great cardiac vein (anterior) and small cardiac vein drain into the coronary sinus (posterior), which empties into the right atrium.
The middle cardiac vein (posterior) also drains into the coronary sinus.

Atrium — heart chamber that collects blood.
Ventricle — heart chamber that ejects blood.
Sulcus (sulci) — groove on the heart's surface marking chamber boundaries.
Aorta — major artery that carries blood from the left ventricle to the body.
Pulmonary trunk — artery that carries blood from the right ventricle to the lungs.
Vein — vessel returning blood to the heart.
Artery — vessel carrying blood away from the heart.
Coronary arteries — vessels supplying blood to heart muscle.
Coronary sinus — sac-like vein draining heart muscle oxygen-poor blood into the right atrium.
Ligamentum arteriosum — connective tissue between the aorta and pulmonary trunk (remnant of fetal circulation).

Know and identify the major heart chambers, arteries, veins, and coronary vessels discussed.
Review diagrams of heart anatomy for spatial understanding.
Prepare for a review of blood flow through the heart in the next lesson.