Chapter 9: timeline of events and structures involved Flashcards
diastolic volume (EDV)
total amount or volume of blood in a ventricle before it contracts
ensystolic volume (ESV)
residual (what remains) after contraction
frank startling law of heart
more filling= more stretching
more stretching= greater blood ejection
cardiac output
volume of blood pumped per minute
sympathetic tone
fight or flight
would increase heartrate and increase venous return
parasympathetic tone
rest and digest
decrease in heart rate
decrease in venous return
diastole 0s-.4s
atria are relaxed
ventricles relaxed
ventricular filling
atrial systole .4 - .6s
atria contract
ventricles relaxed
EDV (total amount or volume of blood in a ventricle before it contracts
ventricular systole .6-.8
ventricles contract
blood enters the arteries
ESV
if stroke volume SV = EDV - ESV what would decrease SV?
decrease EDV
increase ESV
Bachmans bundle
branch that goes from the SA node to the left atrium
- a fiber like structure that conducts electricity or depolarizing event
- main way to depolarize the left atrium
main important part of depolarization
-getting the ventricles to contract forcefully, efficiently, and at the same time
why are the right and left bundle branches insulated?
they are insulated so they do not come in direct contact with the work cardiomyocytes, this is way contraction of the work cardiomyocytes only happens once the purkinje fibers come in direct contatct with the work cardiomyocytes to make them contract from the BOTTOM UP!!
conduction velocity of the SA node
.05 meters/ second
-kind of slow
-
conduction velocity of the VA node
.05 meters /second
-really slow because it gives the atria time to fully contract while the ventricles are still relaxed, before it ever comes streaming down causing the ventricle to contract
what happens if there is no delay of the sa and av nodces meaning what would happen if ventricular and atrial contraction happened at the same time?
your valve would not be able to remain closed because they would be fighting two different pressures that are similar so you could have blood go back into the atria
conduction velocity of bundle of his
2 m/s
conduction velocity of bundle branches
2 m/s
why are perkinje fibers the fasted at 4 m/s
because by the time you get the action potential down to the bottom or apex there is no reason for delay
why are work cardio myocytes slower to depolarize?
their intracellular RMP is -80 mV
the SA nodal cells depolarize quicker ttherefore preventing the work cardiomyocytes from setting up their own beat
spontaneous depolarization
SA nodal cells do not need an outside factor telling them to depolarize , they just do it all on their own
-the dip down to -60 but do not stay at RMP
how many work cardiomyocytes share gap junctions with eachother?
about 11!
this means you can have 11 different work cardiomyocytes sending depolarization to on cell
stroke volume
amount of blood pumped per ventricle per beat
- sv= edv-esv
- refers to how much came out of the ventricle
what would decrease stroke volume?
a decrease in EDV or increase in ESV
-if you decrease EDV less could eject so SV goes down
-if you increase ESV it will decrease SV because it means there is more remaining in the chamber stil
(this is bad because it could be a sign that the heart was unable to handle the amount that was put in there for whatever reason)
