Term 1 - walkins Flashcards
Size of Resting membrane potential is governed by __(how many) factors:________
- The permeability of the neuronal membrane
- Unequal distribution of different ions
There is more K+ ion in ICF than ECF T/F
true
Thee is more Na+in ICF than ECF T/F
False
The electrogenic pump operate as every ___ _______ ion ____, every ___ _______ions ____
every 3 Na+ out, every 2 K+ in
3 factors that cause the unequal distribution of ions when neuronal membrane at rest
- some - ve charged proteins (Pr-) are trapped in cell because of their large size
- Operation of ATPase ( the electrongenic pump)
- Presence of special ion channels in membrane
Two types of ion channels
- Passive channels, which ions can go through continuously
- Active Channels that are gated
types of active ion channels
- membrane potential (Voltage regulated gates )
- Neurotransmitter (Chemical regulated gate)
When neuronal membrane at rest, it is impermeable to ____ ion, but permeable to ____ion
impermeable to Na+ but permeable to K+
K+ ions can’t diffuse out of neuronal membrane T/ F?
False
they can diffuse out until the equilibrium of K+ is reached
What is depolarisation ?
- 70mV changes to +40mV
What is Hyperpolarisation?
- 70mV changes to -90mV
what is Em
Membrane potential
What is repolarisation?
when membrane potential go backs to -70mV
Function of different components of a neuron
Dendrites- reception of income information
Soma- Cell body, contain nucleus & most organelles)
Nucleus
Axon- Transmit the electrical impulse (action potential)
Axon hillock- where axon originates & action potential initated
Axon terminals - Release neurotransmitter
Schwann cell
Node of Ranvier
Types of ions channel in neuron
~ Ligand - gated channel - response to ligand binding
~ Voltage- gated channel - response to change in membrane potential
~ passive Channel
Cells of Nervous system
- Neurons - excitable cell
- Glial cells - support cells
Passive channels can be found______
throughout the neuron; at resting Em
Ligand- gated channels can be found __________
Dendrites & cell body; for synaptic potential
Voltage gated channels can be found _________
- Na+ & K+ channel: throughout, but more in axon (especially in axon hillock); for action potential
- Ca- channels: Axon terminals; Release of neurotransmitter
Local potential is the results of _______ ___________ stimulation of neuron
sub- threshold stimulation
Local potential takes places because _______
the stimulus is not strong enough to generate the action potential
Size of local potential is depends on ________
the strength of the stimulus
local potential is also called ?
graded potential
local potential travel short distant and they can summate T/F
True
