Karius - everything Flashcards
what does the Na+/K+ pump?
3 Na out
2 K in
if nernst is greater (abs value) which gradient dominates?
chemical
what kind of channels are Cl?
what nt’s bind to open the channel?
Ligand-gated
GABA and Glycine
what controls which way ions flow through a channel?
ionic gradient
describe the ClC1 channel
open at rest
closes with depol
what are are the sodium channels like during threshold?
all of them are open
is it possible to get an AP during absolute refractory period?
NO
what happens in a relative refractory period?
harder to get 2nd AP, some Na channels back to closed state
what is a depolarization block?
voltage inactivation
something external is holding Vm more depol than normal ie. drug
how do most APs travel?
via saltatory conduction
what is the result of hyperkalemia?
high K+ in ECF, renal failure, may see a depolarization
what is conduction velocity = to?
mm / time
do AP die away with time or distance?
NO
what is used in direct electrical/chemical communication?
what is the route of transmission?
gap junctions
Intracellular fluid
what are the post-synaptic specializations?
extensive surface area
post-synaptic densities (NT receptors)
what are presynaptic specializations?
mitochondria
vesicles
increased surface area
what are the adrenergic nts?
SEND H
serotonin epi norepi dopamine histamine
excitatory a.a.?
glutamate
aspartate
inhibitor a.a.?
glycine (spinal cord, brainstem)
GABA (CNS)
describe nt release
depol of pre-synaptic term opening of VG-Ca channels Ca influx into terminal binding of Ca conformation change in proteins brings docked vesicles fusion of vesicular membrane with CM creation of fusion pore diffusion of nt into cleft
how is nt remvoed from cleft?
diffusion
natural (NO)
enzymatically via AChE
Re-uptake via Epi/NorEpi
what happens if the nt opens a Na or Ca channel?
what is the nt?
depol
then EPSP
ACh or EAA
what happens if nt opens a Cl channel?
what is the nt?
Cl enters cell
hyperpol
IPSP
GABA or glycine
describe temporal summation
axon has multiple AP traveling with it
both + or both -
describe spatial summation
2 or more synapses simulatenously active
EPSP and IPSP can be ADDED
what is located on the T-tubule?
DHP receptor
where is the ryanodine receptor located?
are they voltage gated?
terminal cisternae (SR)
NO
with depol of the t-tubule membrane, what happens?
Ca is released from the SR and diffuses to area of myofibrils
at rest what is blocking the active sites?
tropomyosin
how is tropomyosin moved out of the way?
Ca binds troponin C, it undergoes conformational change and moves tropomyosin out of the way
what happens after tropomyosin is out of the way?
Pi will dissociate from the myosin head
what happens after Pi dissociates?
ADP dissociates to create the powerstroke
what happens when ATP binds the myosin head?
conformational change so that myosin and actin dissociate
what does energy due to the myosin?
moves the head back into cocked position
when does the powerstroke process stop?
no more ATP or Ca
Ca-ATPase removes Ca from cytoplasm
mechanical forces prevent contraction
where is CrP made?
ATP production?
when is it used?
at myofibril
1:1
during exercise
failure to maintain the energy supply causes fatigue do to what?
nt at NMJ used up
inadequate ATP available
how is creatine made?
CrP + ADP –> Cr + ATP
what 2 things are required for an ionic gradient?
selective cell membrane
Na/K ATPase
