19.1 Heart Anatomy

Heart anatomy and physiology

Mediastinum

The space in the thoracic cavity where the heart is located, medially between the lungs.

Pericardium

The tough membrane surrounding the heart, which separates it from other mediastinal structures.

Pericardial cavity

The space within the pericardium that contains the heart.

Apex of the heart

The inferior tip of the heart that lies just to the left of the sternum.

Base of the heart

The superior surface of the heart where large veins and arteries are attached.

Pulmonary circuit

The pathway that transports deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium.

Systemic circuit

The pathway that delivers oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium.

Epicardium

The outermost layer of the heart's wall.

Myocardium

The thick, muscular middle layer of the heart's wall responsible for pumping action.

Endocardium

The innermost layer of the heart's wall that lines the chambers.

Interatrial septum

The wall that separates the right atrium from the left atrium.

Interventricular septum

The wall that separates the right ventricle from the left ventricle.

Atrioventricular valves

Valves located between the atria and ventricles of the heart.

Semilunar valves

Valves located at the openings that lead from the ventricles to the pulmonary trunk and aorta.

Tricuspid valve

The atrioventricular valve between the right atrium and right ventricle.

Pulmonary veins

The veins that return highly oxygenated blood from the lungs to the left atrium.