Perfusion - Intro Flashcards
What is perfusion?
Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, usually referring to the delivery of blood to a capillary bed in tissue. All tissues require an adequate blood supply for health and life
heart cells AUTOMATICITY
ability to create an electrical impulse
heart cells EXCITABILITY
responds to the created electrical impulse and depolarizes
heart cells CONDUCTIVITY
passes the electrical impulse from cell to cell
heart cells CONTRACTILITY
cardiac cells respond to electrical impulse and they contract
CONDUCTION PATHWAY
SA (sinoatrial) NODE > Internodal Tract > RT & LT Atria > AV (atrioventricular) NODE > Bundle of HIS > Bundle Branches > Purkinje Fibers > Ventricle
SAN > IT > ATRIA > AVN > BHIS > BB > PF > Ventricles
Systole
contraction of myocardium to vesicles: HIGHEST PRESSURE POINT
Diastole
REST PERIOD; ventricles fill with blood
Systolic B/P
HIGHEST PRESSURE inserted against ventricle walls when heart is CONTRACTING
Diastolic B/P
regular pressure when filling with blood
Systolic/Diastolic
HIGHEST pressure/REGULAR pressure
PRESSURE OUT/filling period
Mean arterial pressure or MAP
amount of time it takes to perfuse the organs:
desired MAP = 65+ (want to keep all organs perfusing; reduces risk for organ failure)
MAP formula
systolic B/P + x2 of diastolic B/P / 3
PRELOAD
volume of blood in ventricles at the end of diastole BEFORE next contraction
Do you want high preload?
NO
What can cause high preload?
HYPOvolemia (LT ventricle)
and
HYPERvolemia (RT ventricle)
CONTRACTILITY
strength and vigor of the hearts contractibility during systole
what is the frank starling law?
The greater the stretch of the myocardial fibers = the stronger the contraction
AFTERLOAD
resistance LT ventricle must overcome to circulate the blood throughout the body
Is increased AFTERLOAD good?
No; increased afterload = increased cardiac workload
EJECTION FRACTION or EF %
end diastolic volume ejected with each contraction; will never be 100% (good EF% is 50-70%)
STROKE VOLUME
amount of blood pumped into the aorta with each contraction of the LT ventricle
What is normal cardiac output?
4-8L/min
cardiac workload w/ SYMPATHATIC NERVOUS SYSTEM STRESSORS
SYMPATHETIC NERVOUS SYSTEM = FIGHT OR FLIGHT:
INCREASES the rate of the cardiac system
cardiac workload w/ PARASYMPATHETIC NERVOUS SYSTEM STRESSORS (or lack of)
PARASYMPATHETIC NERVOUS SYSTEM = REST & DIGEST:
DECREASES the rate of the cardiac system
