The Neuron Flashcards
antidromic means
AP current is travelling towards the soma, away from dendrites
orthodromic means
AP current travelling away from Soma, towards the dendrites
resting membrane potential of motor neurons
-40mV to -80mV
resting membrane potential of muscle
-90mV
summation of potentials steps (postsynaptic integration)
neurotransmitters release –> receptor binding –> ion channels open or close –> post synaptic membrane may change –> post synaptic cell integrates (sums) all the EPSPs and IPSPs –> post synaptic cell excited or inhibited –> if excited above threshold action potential generation, message transmitted
neurotransmitter releases from pre-synaptic neuron is stimulated by
voltage gated calcium channels open from AP travelling down pre-synaptic neuron, allowing calcium in, then this stimulates binding of synaptic vesicles with the membrane
what structure makes the motor end plate
membrane of the muscle across from the axon terminal
steps to triggering a muscle contraction
AP arrives at bouton –> depolarization of presynaptic membrane –> Ca enters bouton –> Aah release –> ACh diffuses and combines with nicotinic receptors (ligand gated receptors) –> Na and K move in –> end plate potential –> rapidly activated voltage gated Na channels –> na moves in (AP) –> muscle cell depolarizes –> muscle contraction
ACh with nicotinic is + or -
+
ACh with muscarinic receptor is + or -
-
complexity of nervous system allows for
regulation and flexibility of motor control
OHM’s law is (formula)
V = IR
increased resistance creates
larger voltage for same inout current
increased current produces
larger voltage for same given resistance
axonal conduction speed directly varies with
- axon diameter: increase = increase in speed
- membrane resistance: increased resistance = increased velocity (myelin increases resistance)
