Chordae tendineae – attach cusps of tricuspid valve. Originate from papillary muscles on walls of ventricles. R ventricle pumps blood through pulmonary artery to lungs. Pulmonary valve leads into artery.
* L atrium receives blood from lungs through pulmonary vein. L atrium and L ventricle separated by bicuspid (mitral) valve. L ventricle pumps through aorta to entire body. Aortic valve leads into aorta.
Blood flow Blood low in O 2, high in CO 2 enters R atrium. R atrium passes blood into R Ventricle. R ventricle contracts, blood flows into pulmonary artery (to lungs) Pulmonary vein brings blood high in O 2 back to L atrium.
Blood passes to L ventricle. Pumped through aorta to body. 1 st 2 branches of aorta – R,L coronary arteries – supply blood to heart tissue. Cardiac veins – drain blood, join together to form coronary sinus – dump into R atrium.
Cardiac cycle Heart sounds made from opening and closing of valves. 1 st sound made from recoil of blood against closed AV valves (“lub”) 2 nd sound made from recoil of blood against semilunar valves. (“dup”) Heart murmurs result of incomplete valve closure resulting in swishing noise.
Hormones regulate b.p. Epinephrine, norephinephrine – rise, fall of b.p. Antidiuretic hormone – rise in b.p. Kidneys aid in regulation – drop in b.p. releases renin; renin causes formation of angiotensin.
Circulatory Pathways 1 Pulmonary circulation – pulmonary trunk carries blood from R ventricle. Divides into R and L pulmonary artery, into capillaries. O 2 picked up in lungs, brought back to heart via pulmonary veins.
Arteries 2 Systemic – blood leaves L ventricle into ascending aorta. Branches into R, L coronary arteries (supply heart wall). Aorta curves to back (aortic arch) 3 branches – brachiocephalic, L common carotid, L subclavian.
Inferior vena cava – longest vein in body – great saphenous vein, joins with femoral vein. Abdomen – hepatic portal system – blood from capillaries of digestive tract to liver only. Dumps blood into superior, inferior mesenteric veins.
Diseases 1 Congestive heart failure – can’t pump blood to body. Bad circulation to body increased pressure, fluid leaking in lungs. Caused by damage to cardiac muscle. Symptoms – shortness of breath, swelling in lower legs.
3 Endocarditis – infection of lining of heart due to bacterial infection. Can cause embolus (blood clot) 4 Aneurysm – sac formation in vessel or heart chamber; can produce tear in vessel (hemorrhage)