Nervous system Flashcards
Nervous System
gathers info, decides on a course of action and responds
Sensory neurons
afferent (ascending) pathways to brain
Motor neurons
efferent (descending) pathways from brain
Interneurons
link between sensory and motor neurons, found in the brain and spinal cord
Cell body
carries out basic processes of the cell, stroma ( how neuron receives input)
dendrites
receive message from nearby neurons
axon
transmits electrical impulse (action potential) from cell body down length of neuron
myelin sheath
made up of fats, insulates axon, making transmission faster and more efficient
synaptic terminals (aka axon terminals or terminal branches)
store neurotransmitters, then release them to activate (or inhibit) other neurons
action potential
when a neuron activates, or fires, it generates an electrical current that travels from the start of the axon and travels to the terminals
axon at rest
(not firing) inside of the axon is negatively charged with respect to the outside
axon firing
Inside of the axon is now positively charged
neurotransmitters
chemicals released by one neuron and binding to another. can be either excitatory (encourage firing) or inhibitory (discourage firing) on a neuron. they “duke it out” in which one to fire
serotonin
sleep regulation, appetite, anxiety, and depression. many current antidepressants increase its effects
Dopamine
Emotions, pleasure, attention, movement. Also involved in schizophrenia (too much DNA), Parkinson’s ( too little DNA) and drug abuse
Norepinephrine
emotional arousal/energy
Acetylcholine
memory and learning, muscle activity (black widow venom affects it leading to muscle spasms), alzheimer’s disease involves insufficient production of it
Glutamate
Very common excitatory NT in brain, learning and memory
GABA
very common inhibitory NT in brain, “depressant”, relaxant, effects enhanced by alcohol
Central Nervous system
one larger whole can be broken into two subunits (CNS and PNS).
PNS
has 2 subdivisions; the somatic and autonomic nervous system
Somatic nervous system
think of it as “voluntary” nervous system
Autonomic nervous system
controls autonomic processes, like breathing and body temperature
sympathetic nervous system
activates “fight-or-flight” response
