AP Psychology Unit 1.3a - The Neuron and Neural Firing: Neural Communication and the Endocrine System

Neuron

a nerve cell; the basic building block of the nervous system

Cell Body

Largest part of a typical neuron; contains the nucleus, the cells life support system

dendrites

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

Axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

glial cells

cells in the nervous system that support, nourish, and protect neurons

action potential

a neural impulse; a brief electrical charge that travels down an axon

threshold

the level of stimulation required to trigger a neural impulse

refractory period

the time following an action potential during which a new action potential cannot be initiated

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing.

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons. When released they bind to the receptor sites of the recieving neuron , influencing whether that neuron will generate a neural impulse.

Reuptake

a neurotransmitter's reabsorption by the sending neuron

Endorphins

"morphine within"--natural, opiatelike neurotransmitters linked to pain control and to pleasure.

Agonist

a molecule that increases a neurotransmitter's action

Antagonist

a molecule that inhibits or blocks a neurotransmitter's action

endocrine system

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

Hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues