Heart Anatomy and Physiology

Location of the Heart

Thoracic cavity in the mediastinum, obliquely situated.

Anterior Wall

Front portion containing the right atrium and both ventricles.

Inferior Wall

Bottom portion of both ventricles resting on the diaphragm.

Posterolateral Wall

Back portion, greatest portion of left ventricle; largest muscular wall.

Right vs. Left Side of Heart

Right side has oxygen-poor blood; left side has oxygenated blood.

Cycle of Blood Flow (First Half)

Right Atrium -> Right Ventricle -> Pulmonary Arteries -> Lungs.

Cycle of Blood Flow (Second Half)

Pulmonary Veins -> Left Atrium -> Left Ventricle -> Aorta.

Atrioventricular Sulcus

Groove that separates the atria from the ventricles.

Interventricular Sulcus

Grooves separating ventricles; contain interventricular arteries.

Fibrous Pericardium

Tough, dense outer sac attaching the heart to the diaphragm.

Serous Pericardium

Inner layer with parietal and visceral portions.

Pericardial Space

Space containing serous fluid between pericardial layers to reduce friction.

Pericarditis

Inflammation of the pericardium causing chest pain and breath shortness.

Epicardium

Outermost layer composed of fibrous connective tissue and adipose tissue.

Myocardium

Middle layer of the heart composed of cardiac muscle.

Endocardium

Innermost layer composed of simple squamous epithelium.

Superior and Inferior Vena Cava

Superior carries upper body blood; inferior carries lower body blood.

Pulmonary Veins

Four veins delivering oxygenated blood from lungs to left atrium.

Aorta

Transports oxygenated blood from the left ventricle to the body.

Pulmonary Trunk

Transports deoxygenated blood from the heart to the lungs.

Function of Heart Valves

Gates that prevent backflow to ensure one-way blood flow.

Bicuspid Valve

Left AV valve that prevents backflow into the left atrium.

Tricuspid Valve

Right AV valve that prevents backflow into the right atrium.

Aortic Semilunar Valve

Valve between left ventricle and aorta preventing backflow.

Pulmonary Semilunar Valve

Valve between right ventricle and pulmonary trunk.

Systole

Contraction phase of the cardiac cycle where AV valves close and blood is ejected.

Diastole

Relaxation phase of the cardiac cycle.

Papillary Muscles

Structures that prevent valve inversion and stabilize valve leaflets.

Chordae Tendineae

Connect papillary muscles to valve leaflets to keep them touching when they close.

Sinoatrial (SA) Node

Pacemaker of the heart that initiates the heartbeat and makes atria contract.

Atrioventricular (AV) Node

Receives action potential from the SA node and passes it to the ventricles.

Myocardial Infarction

Condition where a coronary vessel gets blocked by a thrombus or embolus blood clot.

Heart Sounds ("Lubb" and "Dubb")

"Lubb" is closure of AV valves and ventricular contraction; "Dubb" is closure of semilunar valves and ventricular relaxation.