| A | B |
|---|
| neurons | basic cell that makes up the nervous system |
| neuron parts | dendrites, soma, axon |
| glial cells | grey fatty cells that provide support for neurons, deliver nutrients to neurons, produce myelin to coat axons, clean up waste products |
| myelin | fatty substances produced by certain glial cells that coat the axons of neurons to insulate, protect, and speed up neural impulse |
| ions | charged particles |
| resting potential | state of the neuron when not firing a neural impulse |
| action potential | release of the neural impulse consisting of a reversal of the electrical charge within the axon, allows positive sodium ions to enter cell |
| all or none | refers to the fact that a neuron either fires completely or does not fire at all |
| axon terminals | branches at the end of the axon |
| synaptic knob | rounded areas on the end of axon terminals |
| synaptic vescicles | sack-like structures found inside the synaptic knob containing chemicals |
| neurotransmitters | chemical found in the synaptic vescicles which, when released, has an effect on the next cell |
| synapse or synaptic gap | microscopic fluid-filled space between the synaptic knob of one cell and the dendrites or surface of the next cell |
| receptor sites | holes in the surface of the dendrites or certain cells of the muscles and glands, which are shaped to fit only certain neurotransmitters |
| excitatory neurotransmitter | neurotransmitter that causes the receiving cell to fire |
| inhibitory neurotransmitter | neurotransmitter that causes the receiving cell to stop firing |
| agonists | chemical substances that mimic or enhance the effects of a neurotransmitter on the receptor sites of the next cell, increasing or decreasing the activity of that cell |
| antagonists | chemical substances that block or reduce a celll's response to the action of other chemicals or neurotransmitters |
| acetylcholine | excitatory to vertebrate skeletal muscles; excitatory or inhibitory at other sites |
| reuptake | process by which neurotransmitters are taken back into the synaptic vesicles |
| enzyme | a complex protein that is manufactured by cells; one type breaks up acetylcholine because muscle activity needs to happen rapidly |
| sensory neuron | a neuron that carries information from the senses to the central nervous system |
| motor neuron | a neuron that carries messages from the central nervous system to the muscles of the body (also called efferent neuron) |
| interneuron | a neuron found in the center of the spinal cord that receives info from sensory neurons and sends commands to muscles through motor neurons; make up bulk of neurons in the brain |
