Canadian Medical Guide > Anatomy > Cardiovascular System > Heart Terms and Definitions

Heart

	Endocardium - The innermost layer of the heart, comprised of endothelial cells.
	Fetal Heart - The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.
	Heart Atria - The chambers of the heart, to which the BLOOD returns from the circulation.
	Heart Conduction System - An impulse-conducting system composed of modified cardiac muscle and having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
	Heart Septum - The thin membranous structure between the two heart atria or the thick muscular structure between the two heart ventricles.
	Heart Valves - Flaps of tissue that prevent regurgitation of BLOOD from the HEART VENTRICLES to the HEART ATRIA or from the PULMONARY ARTERIES or AORTA to the ventricles.
	Heart Ventricles - The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.
	Pericardium - The fibroserous sac surrounding the heart and the roots of the great vessels.

Heart Medical Definitions and Terms