Ch.3: Biology

central nervous system

brain and spinal cord

peripheral nervous system

all nerve cells in the body that aren’t part of the central nervous system

somatic and autonomic

autonomic nervous sytem

involuntary action

somatic nervous system

voluntary action, controls movement and senses

neruons

basic unit of the nervous system that receives, integrates, and transmits information

parts of a neuron

cell body, nucleus, dendrites, myelin, axon, axon terminal, synapse

nerve cells are powered by _______ and communicate with other nerve cells through ________

electrical impulses

chemical signals

3 basic phases

reception- signals received

integration- signals assessed

transmission- pass on signal

sensory neurons

detect info from the physical world and pass it to the brain

somatosensory

give info from skin and muscles

motor neurons

direct muscles to contract/relax, producing movement

interneurons

communicate within local/ short distance circuits

action potential (neural firing)

electrical signal passing along axon causing release of chemicals from terminal buttons

resting membrane potential

Na+ and K+ contribute to neuron’s resting membrane potential

ions pass through membrane channels, flow of ions controlled by gating mechanisms

sodium- potassium pump

contributes to polarization, 3Na+ out, 2K+ in

active low transporting system

ion channel and gate

ions only travel in their own channels and gates and ion pumps

“leaky” vs voltage gated channels

corresponding ion passes through

gates open/ close depending on level of electrical charge of a neuron

a neuron needs to be more _____ than the outside when at rest

negative

relative refractory period

time period following action potential when a neurons membrane potential is more negative, making it harder to fire again

action potential is generated between ______ and _________

cell body

axon

myelin acts as ________,…

membrane , blocking in ions

nodes of ranvier

unmyelinated sections of axon, ion channels present where the action potential occurs

excitatory signals

depolarize cell membrane, increasing likelihood that the neuron will fire

inhibitory signals

hyperpolarize the cell, decreasing the likelihood that the neuron will fire

all or none principle

when a neuron fires, it fires with the same potency each time, cannot partially fire, although the frequency of firing can vary