Nervous system I

Neurons

carry electrical signal

axon

portion of a neuron that carries the electrical signal

glial cells

supports neurons

what do olgiodendrocytes do?

they make myelin sheaths

how does function differ between myelinated axon and unmyelinated axons

myelinated are faster

resting potential of a neuron is the result of

Na+/K+ pumps

what happens at threshold potential?

axon rapidly depolarizes, action potential initiated, voltage gates Na+ channels open

action potential

dynamic wave of electricity that moves down the axon from the body to the terminal

resting potential

charge if -70mV

depolarization

raises potential, from -70mV to zero

threshold potential

when an axon does not reach a certain level

voltage gated sodium

normally closed, sodium cannot come through them

repolarization

when a nerve cell returns to its negative charge after being activated

synapse

junction between two neurons

What happens when the AP reaches the end of the axon?

as signal travels down, it stimulates the movement of vesicles filled with neurotransmitters

neurotransmitters

either inhibit or stimulate a neuron

myelin sheaths

lipid rich insulators along the axon

neurotoxins

prevent proper functioning of the nervous system

Multiple sclerosis

an autoimmune disease that targets myelin, affected neurons lose ability to carry signals, can affect speech, loss of full function of muscles