Mammalian circulation systemic pulmonary systemic AP Biology What

Mammalian circulation systemic pulmonary systemic AP Biology What do blue vs. red areas represent?

Mammalian heart Coronary arteries AP Biology to neck & head & arms

Coronary arteries bypass surgery AP Biology

§ 4 valves in the heart u u flaps of connective tissue prevent backflow § Atrioventricular (AV) valves u u between atrium & ventricle keeps blood from flowing back into atria when ventricles contract § “lub” § Right side = tricuspid u Left side = bicuspid /mitral between ventricle & arteries prevent backflow from arteries into ventricles while they are relaxing § “dub” § Right side = pulmonary AP Biology AV AV § Semilunar valves u SL Left side = aortic

Mid Ventricular Diastole: • Atria and ventricles are relaxed • AV Valves are open • Semilunar valves are closed Mammals and Birds: • Blood returning to heart passes through the atria and goes into the ventricles passively Atrial Systole: • Atria contract and additional blood gets pushed into ventricles • Blood is pumped into the ventricles until they reach end-diastolic volume (EDV), the max amount of blood in the ventricle Isovolumetric Contraction: Early Ventricular Systole: Blood is non-compressible, so • Ventricles Contract pressure in the chamber • Increased pressure causes AV valves to close increases but volume does not. • Semilunar valves are closed

Late Ventricular Systole: • Pressure forces semilunar valves open • Blood flows out of the ventricles into arteries • Chordae Tendinae prevent AV valves from being forced open (AV valves stay closed); preventing backflow • Ventricle has reached its end systolic volume (ESV) or blood minimum Early Ventricular Diastole: • Ventricles begin to relax, pressure drops • Pressure in ventricles drops below that of the arteries • Backpressure forces semilunar valves to close

Lub-dub, lub-dub § Heart sounds u u closing of valves “Lub” SL § recoil of blood against closed AV valves u “Dub” AV AV § recoil of blood against semilunar valves § Heart murmur u AP Biology defect in valves causes hissing sound when stream of blood squirts backward through valve

Cardiac cycle § 1 complete sequence of pumping heart contracts & pumps u heart relaxes & chambers fill u contraction phase u § systole § ventricles pumps blood out u relaxation phase § diastole § atria refill with blood AP Biology systolic ____ diastolic pump (peak pressure) _________ fill (minimum pressure) 110 ____ 70

Measurement of blood pressure § High Blood Pressure (hypertension) AP Biology u if top number (systolic pumping) > 150 u if bottom number (diastolic filling) > 90