BIO 365S Lecture Notes - Lecture 19: Atrioventricular Node, Purkinje Fibers, Heart Block
Specific pathologies to recognize:
IMC and ICU
1.Arrythmia – irregular heart beat. See all the waves. (top left). Heart
still oks, ut just tells the heat ate is’t ostat/stale.
2.Heart block – (bottom left), signal from atrium to ventricle is blocked.
Ca hae oplete = sigal does’t go though, pitue shos oplete
lok, still has P ae ut sie taffi is opletel loked, does’t go
to ventricles → still depolarize because has AV nodes and purkinje
fies ut usuall do’t do the jo eause SA ode is the doiat
one, AV node takes over, see more P waves than QRS and T = complete
block; or partial heart block = see delay b/w P and QRS, signal delayed
much longer.
3.Fibrillation – not working together, no firing together = no contracting
together; can happen in atrium and ventricle.
-Atrium fibrillation – do’t eod a suatio of P ae, lost that.
Not the end of the world. AV node can still make sure ventricles fire
togethe. You do’t see P, ut see QRS. Patiet o’t die ut ot
pleasant. With blood in atrium, because atrium contraction happens,
blood starts to go (80%) without contraction because of pressure and
gravity. Atrium contraction plays a big role in eeise. Patiet o’t die
because you still have 80% of blood going to ventricles.
-Ventricle fibrillation – Do’t see QRS, all ou see is oise otto
ight; thik usles do’t fie togethe, do’t otat togethe. The
got confused, so need to give them the BIG electrical signal a couple
times = usually they come back; body jumps because in your whole
body has skeletal muscles, and currents trigger contraction.
The heart cycles between contraction(systole) and
relaxation (diastole).
Every less than 1 second, finish 1 cycle. Your heart spend more time in
elaatio stat eause ou heat does’t take a eak, ad the ol
one they take is in b/w contraction (2/3 in relaxation, 1/3 in
find more resources at oneclass.com
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Document Summary
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