CIRCULATORY System Structure of the Heart

Size, Shape, and Location Size of closed fist 5 inches long and 3.5 inches wide, weighs less than 1 pound (12-13 oz.) In _____________ cavity Apex Conical tip Lies on the diaphragm and points to the left of the body Where the heartbeat is most easily felt and heard Four chambers Which are what? *SEE FIGURE 13.3 PG 263*

Layers FIGURE 13-2 pg 264 Pericardium Myocardium Surrounds the heart Double layer of fibrous tissue b/t the 2 layers is a space filled with _________ fluid Thin inner layer called: Tough outer layer called: Myocardium Cardiac muscle tissue Makes up a major portion of the heart

Layers continued Endocardium Septum Smooth tissue Covers the heart valves and lines the blood vessels Provides a smooth transit for the flowing blood Septum Thick, muscular wall separating it into right and left halves *SEE FIGURE 13-4a PG 265*

Structures to and from the Heart Superior and inferior vena cava Large venous blood vessels which bring deoxygenated blood to the right atrium from all parts of the body Coronary sinus From the heart muscle to the right atrium Pulmonary artery and vein Artery: takes blood away from the right ventricle to the lungs for oxygen Vein: bring oxygenated blood from the lungs to the left atrium Aorta Takes blood away from the left ventricle to the rest of the body

Chambers Atria (atrium) Ventricles (ventricle) Upper 2 chambers of the heart Aka auricle Ventricles (ventricle) Have a right and left Lower chambers of the heart *See figure 13-4 pg. 265*

Valves 4 valves which allow the blood to flow in only one direction Tricuspid valve b/t the right atrium and right ventricle 3 points of attachment (cusps) Chordae tendinae: small fibrous bands connecting the edges of the valve to the papillary muscle; prevents inversion of the tricuspid valve Mitral (bicuspid) valve Located b/t left atrium and left ventricle 2 points of attachment

Valves continued Semilunar valves are located where the blood leaves the heart Pulmonary semilunar valve Found at the opening of the pulmonary artery Allows blood to travel from right ventricle into the artery and then into the _____________. Aortic semilunar valve At the opening of the ___________. Allows blood to pass from the left ventricle into the aorta