week 4 patho: the heart Flashcards
which side of the heart pushes blood through pulmonary circulation
The right side
which side of the heart contains bicuspid valves
the left side
which artery of the heart (in coronary circulation) would be the most lethal if there was an issue
the left anterior descending
which two arteries in coronary circulation will contribute to dysrhythmias if there was an issue
the left anterior descending and the circumflex artery
which arteries of the heart supply blood to the SA node
50% right coronary artery and circumflex
define cardiac output
how well the heart pumps blood to tissues
what is end diastolic pressure
the volume of blood in the ventricles at the end of diastole
what issues would increase preload
hypervolemia, regurgitation of cardiac valves, heart failure
define afterload
resistance left ventricle must overcome to circulate blood
which issues can increase afterload
hypertension, vasoconstriction
what are the important electrolytes of the heart
Na, K, Ca
what is collateral circulation
hypasses the arteries have to help with blockage, basically rerouting of arteries around narrowing of arteries so blood can get where it needs to go (kind of like varies)
out of the two factors that determine collateral circulation (genetic predisposition/hypercholesteralemia and chronic ischemia) which is more likely to survive
chronic ischemia necasse they have years to develop good collateral circulation
what is artherosclerosis
formation of gunk in arterial wall, primary cause of coronary artery disease
how occluded does an artery have to be (artherosclerosis) for an individual to show symptoms
75% occluded, to which they will show signs of ischemia with exertion
what is the inner most layer of the heart wall called
the tunica intima
what are some important things about the endothelium of the heart wall
it separates the blood stream from the artery wall, protects the artery wall from toxins
what happens if there is injury to the endothelium of the heart wall
injury to the endothelium will release cytokines which trigger inflammatory response, resulting in atherosclerosis
what are the four stages of atherosclerosis (simplified)
1) tear in lining damages endothelial layer
2) monocytes enter tear and eat LDLs (which also enter tear) making fatty streaks in lining
3) platelets and LDLs release platelet derived growth factor which makes a collagen cap that takes up space and blocks flow
4) collagen can can rupture which blocks artery with thrombus
how does tobacco use trigger inflammatory process in the heart
tabacco triggers epinephrine which elevates heart rate, LDLs, and causes vasoconstriction
how does homocysteinemia cause inflammatory process in the heart
it is an inherited metabolic defect that leads to high levels of homocysteine which is a metabolite of methionine, which is toxic to the endothelium
why are women not as high of a risk for CAD
estrogen is a cardioprotective hormone so females are lower risk of CAD till menopause
what is the frenningham risk score
its a score that shows your risk for a cardiac event
what is the good cholesterol lipoprotein carrier and what is the bad
LDL= bad, HDL= good
cholesterol binds to these
why is HDL good for you
it reduces risk of CAD by removing cholesterol from LDL and stabilising plaques, moves the fat back into the liver to be processed
what are foam cells
dead macrophages that sit on artery walls after they eat all LDL’s, blocking blood flow
what causes angina
an imbalance of the arteries ability to supply O2 to the heart muscle and the hearts need for 02
what does angina feel like
pressure, aching, heaviness, or squeezing (as well as disorientation and acute confusion)
what’s the difference between chronic stable angina and vasospastic angina
chronic: temporary, reversible, predictable, associated with stable plaque
vasospastic: due to spasms in the artery wall, lumen narrows which reduces blood flow to areas (usually from cocane), its acute and life threatening
how does ischemia from CAD cause dyspnea
blood can back flow and enter pulmonary circulation
what is acute coronary syndrome
prolonged ischemia that isn’t immediately reversible, associated with unstable plaque which ruptures and forms a thrombus
usually artery is 90% occluded
what differentiates angina from ACS from CAD?
this chest pain occurs at rest, usually lasts 15-20 mins and isn’t responsive to rest or medication
what usually causes angina for ACS
rupture of stable atherosclerotic plaque and partial occlusion by thrombus
define myocardial infarction
sustained ischemia causing irreversible cell death
what’s the difference between a STEMI and an NSTEMI
STEMI is a full thickness MI, you can tell because it elevates the ST wave of an EKG
NSTEMI is partial thickness
how long can the heart tolerate ischemia during a MI
20 minutes before cell death begins
what would heart rate and blood pressure look like in a person experiencing MI
initially high HR and BP, but as cardiac output decreases then so will BP
what clinical manifestations would you see in an older adult experiencing acute MI
sudden onset confusion, fatigue, anxious, dizziness (atypical symptoms)
why would someone experiencing MI have dyspnea
due to pulmonary edema from backup of blood into pulmonary circulation
which cardiac enzyme is the most helpful in detecting MI
Troponin is elevated in STEMI and NSTEMI, it rises 3-12 hours after onset of MI
how to cardiac enzymes help with identifying an
MI
Cardiac enzymes are released everytime we have organ damage and cel death and tell us if there’s cardiac damage and how bad it is
what happens to necrotic tissue after MI
neutrophils and macrophages remove all necrotic tissue, it is replaced with scar tissue after 2-3 months
which coronary artery feeds pacemakers of the heart in most people
the right coronary artery, circumflex feeds blood to the other half of AV node
