8-27 Cell Biology Flashcards
;what are the basics of an action potential
gatedd ion chanels
hat is one of the requirement of the AP?
that it reaches a threshold potentaial
what is an refractory period
the period that it taes for the sodiums channels o ractiad after they deacivated
what if there was no calcim channel in the heart muscles cells
the action potental would look like the nerve acton potential an itawould not have that long action potential duation
what is one of the n diereces for sletal nd caraca cells n ho the are ctited?
the heart cells are electrically conneced through gap junctions at thentercalated disk and seletal cells re not connectted
describe action potential propagaton
the cell s deplored o h threshold h allows the sodium channel open and depolarize and fre an AP, and then a local current flows and this will then depolarize the surrounding tissue or cell, then the AP propergates
how is AP dfferen from a wire conducing eleccity
the cell is no very conducve and t mut propigate he wave of poteal
what would be the reslt of a sodium channel blocker
local anesthetic
how is the spacial properggationn of AP different in skeletal and cardac cells
the cardiac cell propagates in three demensions and the nerve only propagaes down the axon of the nerve
what are some conditions that decresadw tha action potenal
inactivate sodium channels; application of local anesthetics like lidocaine that block the sodium channels; close the gap junctions. decreases cell diameter. this increases the resistance
what happens durring hypercholemia
this is the sodium high condition. this will depolarize the cell and inactivates the sodium channels and then you will get a week contraction or no contraction.
how do AP cause contraction:
in the skeletal: The AP will travel down the t-tubules and thei will cause the sarcoplasmic reticulum to release the calcum that will then cause the conltraction
what is the general cycle ofexcitation-contraction coupling
AP leads to calcum rise and this leads to force
describe calcium induded calcium rrelease
a little bit of callcim comesin the ca channel and hs activates RyR and opens the SR that will release ca and this will cause contraction. SERCA will aactely pump the ca back in. and na\ca atpase will pump ca out and ca pump also pump it out.
what would happen to the rate or relaxation if SERCA is blocked
slow the contraction relaxation rate down.
what if you releases more or less ca from the T-tubules:
you will get a stronger contraction
how do you get a stronger contraction in cardioac and skeletal
more ca release due to epinephrin and neuraepinephrin and in skeletal it is thourgh recruitment of more cell contraction fibers.
what hapens if you block the ca current in cardiac celss
then you awill shorteN THE AP and you will not hget a contractionl in the cell
how is the skeletal muscle contraction different
the channel from the tubule physically blocks the calcium channel from THE SR. and there are no ca pumps out of the cells
what if he neuron to a muscl is cut
no contraction! there is only one connction per mcle
what is achemical synapse and what is the cardiac comparison
the neurons individual onctacdt the muslce cells and pass acetylcholine to the mucle cell and tat binds to ligand gated channel that oppens and allows sodium to enter and depolarizes an then the sodium ion channels open nd properate the AP. in hear use gap junction
How to remmovet the atecholine from the synapse
acetylcholeneestterae eats the signal
what is an EPP in a skeletal muscle cell
this is the end plate potentail that will be caused by release of the acytelcholine in the cell
what will epinephrin and noreepinepherin do to the skeletal muscle cell contration
nothing
