right ventricle characteristics
has thin walls; develops low pressure when pumping into the pulmonary circuit to and from adjacent lungs
why is low pressure necessary in the right ventricle?
because the pulmonary capillaries at the gas-exchange surfaces of the lungs are very delicate
left ventricle characteristics
has thick walls
why are thick walls in left ventricle necessary?
because it pumps blood throughout the systemic circuit
components of AV valves
1. ring of connective tissue attached to the fibrous skeleton of the heart; 2. cusps; 3. chordae tendineae; 4. papillary muscles
what are the two semilunar valves called?
aortic valve and pulmonary valve
functions of the semilunar (aortic and pulmonary) valves
guarding the exits of the left and right ventricles to maintain one-way flow of blood
backflow of blood
what prevents regurgitation?
flow of blood through valves in only one direction
what causes heart sounds?
closure of valves and rushing of blood through the heart; can be heard during auscultation
supplies blood to the muscles of the heart to meet the high oxygen and nutrient demands of the cardiac muscle cells
where do coronary arteries originate?
at the base of the ascending aorta; give rise to two branches
what does right coronary artery give rise to?
right marginal branch and posterior interventricular branch
what does left coronary artery give rise to
circumflex branch and anterior interventricular branch
what is anastomoses?
interconnections between arteries that ensure a constant blood supply
what do the great and middle cardiac veins do?
carry blood from the coronary capillaries to the coronary sinus
what do the anterior cardiac veins do?
drain the anterior surface of the right ventricle and empty directly into the right atrium