Neuron and resting potential Flashcards
parts of a neuron and description
- dendrites - many branched aspects
- body (soma) - genetic and metabolic center of the cell
- axon - fiber for transmission
- terminals - chemicals come out
2 types of transmission in nerve and where
- electrical - dendrite, body, axon
2. chemical - terminal
direction of transfer in nerve
unidirecitonal from dendrites to terminal
3 types of neurons and descriptions
- multipolar - numerous dendrites, single axon
- bipolar - two processes arise from body - one to dendrites, one to terminal
- pseudounipolar - single process arises from body and splits into the two directions
2 processes of pseudounipolar
- periperhal - joins peripheral nerve
2. central - goes to CNS
where are different neurons located
- multipolar- most common - interneurons and motor
- bipolar - special senses
- pseudounipolar - somatic and visceral sensory neurons
what is electrical communication within a cell
transmembrane potential
what is general voltage
-70 to ECF
what is graded potential and where does it occur
- amplitude based on strength of stimulation
- dendrites and cell bodies
what is fixed amplitude and where
- fixed amplitudes, stength based on frequency
- in axon
how do dendrite increase surface area
increase in spines
what does cytoplasm contain
cytoskeletal proteins, mitochondria, ER, ribosomes
what is stim. from sensory neurons and what does it produce
response to stim. generates receptor potentials
what is stim in non-sensory neurons and what is generated
response from NT binding - causes synaptic potential
what demarcates the beginning of an axon
spike initiations zone
where is spike initiation zone in various neurons (2)
- multipolar neurons - axon hillock next to cell body
2. pseudounipolar - where the dendrites coalesce
where are ribosomes located and what is the significance of this
not in axon - means they cannot produce their own proteins and must be transported from cell body
what is name of terminal branching of axons
axon collaterals
what is bidirectional axon transport called
axonal transport
what is direction of anteriograde transport
body to terminal
what are 2 types of anterior transport
- fast - 400mm/day
2. slow - 50mm/day
what does fast transport move
membrane bound substances, mitochondria, macromolecules
what directs fast transport
kinesin - ATP microtubules
what does slow transport move
diffusion of cytosolic and cytoskeletal proteins
what does retrograde transport move (3)
- old garbage - endosomes and mitochondria
- NGF during development
- can move viruses etc - bad
what is movement source of retrograde
dynein
what are 2 conditions for an ion to move through channel
- external force must induce - electrochemical gradient (electric+concentration)
- channel must be permiable
what are 2 types of channels
- nongated - always open
2. gated - only open in certain conditions
3 types of gated ion channels
- voltage gated
- ligand gated
- mechanically gated -
what ions are greater in and out of cells
out - Na, Cl, Ca
in - A and K
what is leak channel
allows slow leak of K out of cell so ICF is -ve
what 3 ways can a charge become more postive
- more Na conductance
- more Ca conductance
- Less K conductance
what 1 way may the charge become more -ve
K conductance increased - causes hyperpolarization
