Chapter 14 (Part 3) Flashcards
a premature atrial contraction will be followed by what?
premature ventricular contraction
premature atrial contraction will be followed by premature ventricular contraction. so what?
prevents proper filling of heart chambers and therefore, insufficient amount of blood pumped out of the heart
what is fibrilation?
loss of coordination of electrical activity of the heart (contractile cells are not synchronized)
what are the two types of fibrilation?
atrial and ventricular
what ensures directional flow through the heart?
cardiac cycle
what’s the big deal with the cardiac cycle?
ensures directional flow through the heart
heart valves open passively due to?
pressure
all valves closed prevents what?
backflow
what is the name of cardiac cycle phase 2?
isovolumetric contraction
what is an isovolumetric contraction?
closes AV valves before opening SL valves
what is the name of cardiac cycle phase 4?
isovolumetric relaxation
what is isovolumetric relaxation?
closes SL valves before opening AV valves
some blood is still in the _____ in isovolumetric relaxation?
ventricles
what nerve of the PNS acts on SA and AV nodes to lower heart rate?
vagus nerve
what nerve of the SNS acts at SA and AV nodes to increase HR and the ventricular myocardium contraction force to increase stroke volume
sympathetic cardiac nerve
parasympathetic control slows down heart rate: Ach binds to ____________ G protein coupled receptors that inhibit adenylate cyclase activity
muscarinic cholinergic
increasing CO by increasing stroke volume by extrinsic factors. what are they? (3)
- involves the SNS and norepinephrine increases Ca+2 influx through LTCCs
- increases contractile strength of heart = lowers end systolic volume
- NT binds to G ptn coupled receptors = cAMP = PKA = more Ca+2 through L-type Ca+2 channels = more crossbridge formation
describe Frank-Starling effect vs. alternate troponin effect?
F-S: with more blood being returned to the heart, heart muscle is stretched more and inherently contracts more forcefully = increase in stroke volume =more blood pumped out
- troponin is altered = binds Ca+2 more readily = displaces more tropomyosin = … more crossbridging and stronger contractions
“heart muscle fiber length is not at optimal length.” what does that mean?
cardiac sarcomeres are shorter
summary of factors slide
nitroglycerin treatment for heart attack causes vasodilation slide
how was functional heart muscle regenerated in de-cellularized human hearts
injected the induced pluripotent stem cells into the de-cellularized ventricle
