Neuroanatomy, Neurotransmitters, and Nervous Systems

Neurons

Individual nerve cells that make up our entire nervous system

Dendrites

Rootlike parts of the cell that stretch out and grow to make connections to other neurons

Soma

Contains the nucleus and other parts of the cell needed to sustain its life

Axon

Wirelike structure ending in the terminal buttons that extends from the cell body

Myelin Sheath

Fatty covering around the axon that speeds neural impulses

Terminal Buttons

The branched end of the axon that contains neurotransmitters

Neurotransmitters

Chemicals that enable neurons to communicate; fit into receptor sites like a key in a lock

Synapse

The space between terminal buttons of one neuron and dendrites of the next

Action Potential

Electric message firing that travels down the neuron when enough neurotransmitters are received

All-or-None Principle

A neuron fires completely or not at all

Acetylcholine

Involved with motor movement; lack is associated with Alzheimer’s

Dopamine

Involved with motor movement and alertness; low = Parkinson’s, high = schizophrenia

Serotonin

Involved with mood control; lack is associated with depression

Sensory Neurons

Take information from the senses to the brain (afferent)

Interneurons

Take messages and send them elsewhere in the brain/spinal cord

Motor Neurons

Take information from the brain to the rest of the body (efferent)

Central Nervous System

Brain and spinal cord (nerves housed in bone)

Peripheral Nervous System

All nerves not encased in bone; includes somatic + autonomic

Parasympathetic Nervous System

Slows the body down after a stress response

Autonomic Nervous System

Controls heart, lungs, organs; regulates stress responses

Sympathetic Nervous System

Mobilizes body for stress; “fight or flight”