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34 terms

Nervous system

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resting potential
electrical charge across the cell membrane of a neuron
threshold
minimum level of stimulus needed to activate a neuron
action potential
reversal of charges across the cell membrane of a neuron as an impulse passes
brain stem
connects brain to the spinal chord; controls information going in and out of the brain; controls involuntary actions
thalamus
recieves messages from sensory receptors and relays to proper part of cerebrum
spinal chord
controls reflexes; carries signals from brain to the rest of the body
sensory division of peripheral nervous system
transmits impulses from sensory neurons to CNS
motor division of the peripheral nervous system
transmits impulses from CNS to muscles and glands
somatic nervous system
part of motor division; regulates voluntary activities
autonomic nervous system
part of motor division; regulates involuntary activities
impulse
the electrical discharge that travels along a nerve fiber
hormones
chemical "messengers" of the endocrine system that are released into the blood
protein hormones
class of hormones that cannot pass through the cell membrane; less likely to be stored in the body
steroid hormones
class of hormones that can pass through the cell membrane; can be stored in the body
prostaglandins
local hormones that do not enter the bloodstream
positive feedback
Process that amplifies a small change (Reinforce change)
negative feedback
a response that opposes the original stimulus
acetylcholine
Neurotransmitter chemical released at the ends of some nerve cells
motor nerves
Carry messages away from the brain and spinal cord to muscles and organs
sensory neurons
type of neurons that usually has long dendrites and short axons, and carry messages from the body to the CNS
motor neurons
usually has long axons and short dendrites, and transmits messages from the central nervous system to the body
interneurons
found only in the CNS where they connect neuron to neuron and gives quick responses
saltatory conduction
process of impulses jumping from node to node
sodium potassium pump
maintains unequal concentration by actively transporting ions against concentration gradients
stimulant
makes membrane more permeable to sodium and increases synaptic transmission of impulses in brain (eg. caffeine, cocaine, mescaline, nicotine)
depressants
inhibit an impulse at synapse (eg. anesthetics, botulin, curare, serotonin)
psychedelic drug
affects role of serotonin and alter perception (eg. LSD, marijuana)
analgesics
they relieve pain by interfering with transmission of pain impulses to cerebral cortex.
cerebral cortex
controls intelligence, reasoning, learning, memory
hypothalamus
regulates homeostasis, links nervous system to endocrine system
cerebellum
controls muscles, posture, balance, causes continuous state of muscle contraction
medulla oblongata
involved with regulation of heartbeat, breathing, vasoconstriction, reflex
cranial nerves
takes impulses to and from CNS (in PNS)
spinal nerves
takes impulses to and away from spinal chord