1.3 neural firing

action potential

all-or-none electrical impulse, carries a message away from the cell

axon

extends from cell body and passes electrical signal to other neurons, muscles, or glands

axon terminal

end of an axon, neurotransmitters are stored and released into the synapse

dendrite

detects the signal

myelin sheath

fatty tissue that insulates the axon, speeds up travel time

glial cells

support neurons through insulation, waste removal, create myelin sheath

multiple sclerosis

myelin degrades or is not produced

excitatory neurotransmitters

cause action/movement

inhibitory neurotransmitters

slowing down/less likely to cause action potential

dopamine

reward system,influences movement, learning, attention, emotion, both excitatory & inhibitory

oversupply —> schizophrenia

undersupply —> parkinson’s

serotonin

affects mood, hunger, sleep, arousal, can be both excitatory & inhibitory

undersupply —> depression

norepinephrine

controls alertness & arousal during stress or fight-or-flight, can be both excitatory & inhibitory, glucose levels, blood flow

undersupply —> depressing mood

glutamate

most abundant excitatory neurotransmitter, involved in memory

oversupply —> overstimulates the brain, causes migraines or seizures

GABA (gamma-aminobutyric acid)

inhibitory, regulates muscles, relaxation into sleep, balance, calms neural firing

undersupply —> seizures, tremors, insomnia

endorphins

produced by CNS, natural pain killers, feeling of well being, natural opiate

undersupply —> more sensitive to pain

substance P

transmits pain signals from the body to the brain

acetylcholine

excitatory/inhibitory, learning, memory, muscle action

undersupply —> alzheimer’s

oversupply —> muscle spasms/convulsions

adrenaline (epinephrine)

triggers fight or flight, adrenal glands, stress response

leptin

produced by fat cells, promotes satiety, suppresses appetite

ghrelin

stimulates appetite

melatoin

regulates sleep-wake cycle/circadian rhythm

oxytocin

bonding hormone, sexual reproduction, breast milk production

agonists

activation, molecule that increases a neurotransmitters action

antagonist

inhibition, molecule that blocks a neurotransmitters action

psychoactive drugs

drugs that change your perceptions and moods by altering brain chemistry

stimulants

drugs that speed up the body’s functions & excite neural activity

caffeine

mild stimulant, blocks sleep-promoting receptors

nicotine

body develops high tolerance, agonist for acetylcholine

amphetamines

speed up body functions cause significant mood changes/energy increases, treat ADHD

cocaine

addictive stimulant derived from coca plant, produces fast rush of euphoria, blocks reuptake of dopamine, serotonin, and norepinephrine

ecstasy

synthetic stimulant & mild hallucinogen, releases dopamine & serotonin, blocks their reuptake, emotional warmth and social connectedness

depressants

reduce neural activity & slow down body functions, lowers heart rate, decreased blood pressure, slowed breathing

alcohol

disinhibitor, slows brain activity, boosts GABA, lowers inhibitions, impairs judgement

barbiturates

tranquilizers, prescribed to induce sleep & reduce anxiety, impair memory & judgement

large doses —> respiratory depression, coma, death

opiates

endorphin-mimicking pain killers, lessen pain and anxiety, euphoric, causes brain to stop producing endorphins

hallucinogens

psychedelic drugs, distort perceptions, evoke sensory images without input

LSD

synthetic hallucinogen, “acid”, alters serotonin receptor action, emotional & visual trip, geometric patterns, vivid colors, separation from body