cardiac system 5 Flashcards
what is afterload
arterial blood pressure
what is afterload for the left venrticle
aortic pressure
what is afterload for the right ventricle
pulmonic pressure
what increases the pressure required for the ventricles to eject blood
either blood pressure or a stenotic valve
therefore an increase in afterload decreases stroke volume
what does an increase in afterload caues
a decrease in stroke volume
what does reducing blood pressure lead to
decrease the pressure required of the ventricle to eject blood leading the heart to try and compensate- leading to enlarged heart muscles- hypertrophy to reduce wall stress
heart failure
inability of the cardiac output to keep pace with the bodys demands for supplies and removal of wastes
what does heart failure affect
either or both of the ventricles causing them to progressively weaken and faill
what does inabiliyt of a ventricle to pump blood cause
blood to become congested or backed up, in the veins leading to the ventricle
what is heart failure caused by
heart attack or impaired coronary circulation
prolonged pumping against chronic afterload- high BP, stenotic vale
prime defect of heart failure
a decrease in cardiac contractility- a weakend heart
decompensated heart failure
- conjestive heart failure- point at which heart can no longer pump out a normal stroke volume despite compensatory measures
what happens in conjestive heart failure
cardiac muscle fibres are stretched to operating in the descending limb of the length- tension curve of the frank starling law
blood cannot enter and be pumped out and venous system dams up
what is heart muscle suppleid with
oxygen and nutrients by blood delivered to it by coronary circulatin and not from bloood within heart chambers
what blood does the heart receive- systole and diastole
most of its own blood supply that occurs during diastole
during systole- coronary vessels are compressed by contracting heart muscles
coronary blood flow- variety
normally varies to keep pace with cardiac oxygen needs
atherosclerotic coronary artery disease
pathological changes within coronary artery walls that diminish blood flow through the vessles
this is the leading cause of death in caanda
what does atherosclerotic coronary artery disease cause
myocardiac ischemia and possibly lead to acute myocardiac infractions
three mechanisms of atherosclerotic coronary artery disease
- profound vascular spasm of coronary arteires
- formation of atherosclerotic plaques
- thromoembolism
posssible outcomes of acute myocardial infraction
immediate death
delayed death from complications
immediate death of acute myocardia infraction
acute cardiac failure occuring because heart is too weka to pump effectively to support the body tissues
fatal ventricular fibrillation brough about by damage to the specialiezd conducting tissue occruing because the wekaened heart is deprived of oxygen
delayed death from complications in acute myocardial infraction
fatal rupture of the dead degenerating area of the heart wall
slowly progressing congestive heart failure where the heart becomes unable to pump out all the blood returned to it
