Unit 1.3a: Neural Communication and the Endocrine system

neurons

nerve cells, the building blocks of the nervous system

cell body

the part of a neuron that contains the nucleus

dendrite

receives messages from other cells

axon

the long part of a neuron that sends messages to other cells

myelin sheath

a fatty covering around the axon that helps messages travel faster

glial cells

cells that support and protect neurons

action potential

a brief electrical charge that travels down an axon

threshold

the minimum amount to stimulation needed to start a nerve signal

refractory period

a short rest after a neuron fires before it can fire again

all-or-none response

a neuron either fires completely or doesn’t fire at all

synapse

the tiny space between two neurons where they communicate

neurotransmitters

carries signals from one neuron to another

reuptake

when a neuron takes back neurotransmitters

endorphins

natural chemicals in the brain that reduce pain

agonist

boosts a neurotransmitter’s effect

antagonists

blocks a neurotransmitter’s effect

endocrine system

the body’s slow communication system that uses hormones

hormones

messengers that travel through the blood and affect the body