CARDIOVASCULAR SYSTEM By: Ivanna Sorensen Lucia Tata Agustin Primak Joaquin Mingrone

Heart Arteries Veins Capillaries STRUCTURES

HEART CHAMBERS Atria: upper two chambers of the heart. Ventricles: lower two chambers of the heart. HEART WALL Epicardium: the outer layer of the wall of the heart. Myocardium: the muscular middle layer of the wall of the heart. Endocardium: the inner layer of the heart. HEART

HEART CARDIAC CONDUCTION Atrioventricular Bundle: bundle of fibers that carry cardiac impulses. Atrioventricular Node: a section of nodal tissue that delays and relays cardiac impulses. Purkinje Fibers: fiber branches that extend from the atrioventricular bundle. Sinoatrial Node: a section of nodal tissue that sets the rate of contraction for the heart. HEART

ARTERIES THE THREE LAYERS Tunica Adventitia: This is the strong outer covering of arteries and veins, which consists of connective tissues, collagen and elastic fibers. Tunica Media: This is the middle layer and consists of smooth muscle and elastic fibers. Tunica Intima: This is the inner layer, which is in direct contact with the blood flowing through the artery. It consists of an elastic membrane and smooth endothelial cells. The hollow center through which blood flows is called the lumen. The endothelium has long been viewed as an inert cellophane-like membrane that lines the circulatory system with its primary essential function being the maintenance of vessel wall permeability. ARTERIES

THE THREE LAYERS Tunica Adventitia: the strong outer covering. It is composed of connective tissue as well as collagen and elastic fibers. These fibers allow the veins to stretch to prevent overexpansion due to the pressure that is exerted on the walls by blood flow.
 Tunica Media: the middle layer of the walls. It is composed of smooth muscle and elastic fibers. This layer is thicker in arteries than in veins.
 Tunica Intima: the inner layer. In some veins the tunica intima layer contains valves to keep blood flowing in a single direction. VEINS

Form the connection between veins and arteries Form the connection between veins and arteries. The capillary bed is a vast expanse of very small vessels forming a network throughout the muscle. However, their main function is not transporting blood. They are specially designed to allow the movement of substances. Capillaries walls: are one cell thick, comprised only of endothelial cells, which allows substances to move through the wall with ease. The cross-sectional area of capillaries within an average size muscle would be very large. This allows a fast and efficient transfer of oxygen-carrying red blood cells. CAPILLARIES