Chapter 9: timeline of events and structures involved Flashcards Preview

Human Body Lecture > Chapter 9: timeline of events and structures involved > Flashcards

Flashcards in Chapter 9: timeline of events and structures involved Deck (25):

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


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)


How would an increase in sympathetic tone impact cardiac output

-cardiac output has to match the oxygen demand of its tissues that will be detected by the brain and the brain with then increase the HR
-Sympathetic tone increases the Heart Rate and Increases venous return also INCREASING EDV then increasing CO