CNS AND NEURONES Flashcards
CNS
prim internal com system
nervous system
collect,process,respond to info
cord working of different organs and cells to body
spinal cord and brain
sc= ext connected to brain via brain stem respon for reflex actions
b= source of conscious control and decision making
2 h connected by corpus callousum, contralateral control
PNS
transmits messages to and from CNS
dendrites
axon
schwann cell
node of ranvier
axon terminal
receives neruo from neighbouring cells
carries EI away from cell body
form mylein sheath
gaps in mylein sheath
com to next neuron in the chain across a synapse
sensory
carries messages from s recepotrs along nerves in pns to cns
long dend, short axon
relay
connect to other neurones
short dend and axon
motor
cns to pns to effectors eg muscles and glands
short dendrites, long axons
hot pan reflex
touch hot pan= s receptors on skin detect pain
pass ei to cns>relay>spinal cord
motor travels away from cns to muscle
effect pulling hand away
action potential
ei move down axon to stimulate release of neuro to another neuro
-70mv so inside neg than out= polarised
so stimulus causes depolarise< more positive =reached threshold
synaptic transmission
ap arrives at end of axon terminal at pre synaptic
vesicles w neuro move towards memb of neuron
neuro released in synaptic gap
diffuse across synaptic cleft from pre to post and bind to specific receptors
reabs by pre via reuptake and broken down or enz
reabsorption
reabsorbed by uptake pump to use neuro again
enz break neuro within synaptic cleft
excitatory neuro
after bonding to receptors= more depolarise = threshold potential> inc likelihood of ap firing
inhibitory neuro
post syn= hyperpolarised= move n further away fro thresehold > red likelihood of ap firing
summation
net effect is excitatory= post sn likely to fire
inhibitory= post sn less likely to fire
