Week 4-Nervous system pt2 Flashcards
What is a resting membrane potential (RMP)?
charge difference across the plasma membrane AT REST
Neg inside
pos outside
What charges are inside and
outside of the cell at rest?
I-negative
O-Positive
Why is it necessary to have a RMP in neurons?
RMP exists because of unequal electrolyte
distribution between extracellular fluid
(ECF) and intracellular fluid (ICF)
How does a resting membrane potential exist in a cell—describe the processes occurring and ions involved that result in a resting membrane potential
potassium ions leak out
Na/k pump- pumps 3 na out and 2 k in (losing positive-helps make more negative)
Negatively charged proteins stay inside cell
Level of Na and K inside/outside of cell
Na
I-small
o-large
K
I-large
o-small
action potential
electrical signal sent down axon
Describe how an action potential is generated starting with a stimulus—describe
the processes involved
1- dendrite takes in stimulus to cell body
2-allows na to enter
2-goes into depolarization
Followed by repolarization
a. What could act as a stimulus?
chemical or sensory stimuli
b. Describe what occurs during depolarization phase—describe flow of specific ions and how the membrane potential changes
A Stimulus causes membrane to become more positive
(toward zero) by letting Na+ into the cell
-Allows Na in
-Causes sodium channels to open-causing more sodium to roll into cell
-Each specific channel opens based on its specific threshold-goes down the line, has to get to a specific positivity to open
Makes inside more positive
Threshold
Amount of positivity it takes to open the channel
. Describe what occurs during repolarization phase—describe flow of
specific ions and how the membrane potential changes
occurs when the inside of the cell becomes
a certain positive number
-Na channels close at a certain positivity
-once they close, k channels open
-allow for k to escape out of cell, making cell more negative
Differentiate between continuous conduction and salutatory conduction of an action potential
c- Continuously polarizing and repolarizing until you reach the end of the axon-action potentials - Na and K gates opening and closing
s-Uses myelin- essentially get to skip over the places that are myelinated, makes polarization and depolarization faster
Give location of cell bodies of preganglionic neurons of sympathetic divisions
T1-T12
L1-L2
Give location of cell bodies of preganglionic neurons of
parasympathetic divisions
C.N. III, VII, IX, X (3,7,9,10)
in spinal cord in S2 – S4
In general—where are the ganglion located in the sympathetic versus the
parasympathetic division?
S-Generally very close to spinal cord (Pre-short and post-longer)
P-closer to tissues- (pre-longer and post-short)
