UNIT 1 LESSON 3

THIS IS ONLY UNIT 1 LESSON 3 - THE NEURON & NEURAL FIRING

neurons

specialized cells that transmit electrical signals

function: carry out MOST of the brain’s communication

action: sends messages from the brain to the body & back

glial cells

the brain’s “support staff”

function: protect, nourish, and clean up after neurons

action: maintains the environment for neurons to function properly

cell body (soma)

the neuron’s control center

function: houses the nucleus and produces energy for the cell

dendrites

the “listeners” of the neuron

function: receive incoming signals from other neurons

axon

the “talker” of the neuron

function: sends signals to other neurons or muscles

myelin sheath

fatty layer around the axon

function: speeds up electrical signal firing

synapse

small gap between neurons where communication occurs

function: transfers signals using neurotransmitters between neurons

action: allows the brain to process complex information by connecting neurons

central nervous system

brain and spinal cord

role: process information and control actions

neurons: inter neurons

peripheral nervous system

nerves outside the CNS

role: transmits signals to and from the CNS

neurons: sensory neurons & motor neurons

reflex arc

a rapid, automatic response to a stimulus; bypass the brain for a quicker reaction

action potential

a brief electrical charge that travels down the axon; triggered when the neuron reaches the threshold

all-or-nothing principle

a neuron either fires or it doesn’t, there’s no halfway

depolarization

when a neuron’s charge becomes less negative, leading to firing

refractory period

after firing, the neuron needs time to reset before firing again

resting potential

the state of a neuron when it’s ready to fire but hasn’t yet

neurotransmitters

chemica messengers that transmit signals across the synapse

excitatory neurotransmitters

encourage neurons to fire

dopamine

involved in reward and motivation

norepinephrine

arouses alertness and energy

glutamate

the most common excitatory neurotransmitter, linked to learning and memory

substance p (the pain messenger)

neurotransmitter involved in sending pain signals to the brain; released by sensory neurons in response to injury or stress & increases blood flow to the area, causing inflammation

effects of substance p

too much: chronic pain

too little: reduced sensitivity to pain

inhibitory neurotransmitters

prevent neurons from firing

GABA

calms the nervous system

effects of GABA

too much: overly tired, overly sedated, normal functions are impaired

too little: cause anxiety and insomnia

seratonin

regulates mood and sleep

effects of serotonin

too much: hallucinogens

too little: associated with depression, mood disorders, and ocd

endorphins

natural painkillers

effects of endorphins

too much: body ignoring signals of pain, risking injury

too little: feeling significant pain

multiple sclerosis

the myelin sheath being damaged, slowing down or blocking signals

myasthenia gravis

an autoimmune disorder where acetylcholine receptors are attacked, leading to muscle weakness

endocrine system

a slower communication system that uses hormones instead of neurotransmitters

hormones

chemical messengers that travel through the blood stream and affect behavior and mood

adrenaline

increases heart rate & energy

oxytocin

influences bonding and social behaviors

leptin

regulates hunger and fat storage

melatonin

regulates sleep-wake cycles

ghrelin

stimulates hunger

effects of dopamine

too much: addictions starting, schizophrenia

too little: parkinson’s and depression

effects of norepinephrine

too much: anxiety

too little: depression and mood disorders

effects of glutamate

too much: overstimulate the brain, causing migraines & seizures

too little: insomnia, concentration problems, mental exhaustion

effects of acetylcholine

too much: severe muscle spasms

too little: alzheimer’s and dementia

psychoactive drugs

substances that affect brain activity and lead to changes in perception, mood, or consciousness

neurotransmitter effects

psychoactive drugs change how neurotransmitters operate by either enhancing or inhibiting their function

agonists

drugs that mimic neurotransmitters or enhance their actions

example: opioids (such as heroin) act as agonists for endorphins, reducing pain

antagonists

drugs that block neurotransmitter activity

example: some antipsychotics block dopamine receptors to reduce hallucinations

reputake inhibitors

drugs that prevent the reabsorbtion of neurotransmitters, increasing their activity

example: cocaine blocks dopamine reuptake, causing an intense “high”

stimulants

speed up body functions and enhance energy

examples: caffeine, cocaine, methamphetamines, and ecstasy all boost dopamine, norepinephrine, and seratonin levels, creating heightened alertness and energy

caffiene

worlds most widely used stimulant, often consumed in coffee

effects: produces dopamine, seratonin, and norepinephrine in the brain

cocaine

the worlds most powerful natural stimulant now known (central active ingredient of cocoa plant)

effects: makes users feel excited, energetic, talkative, and even euphoric

amphetamines

a stimulant drug that is produced in the laboratory

function: stimulate the CNS by increasing the release of dopamine, norepinephrine, and seratonin

methamphetamines

a powerful amphetamine drug, illegal substance (crystal meth), super stimulant, which can include roughly 8 hours of heightened energy or euphoria

effects: increases dopamine, seratonin, and norepinephrine

depressants

slow down bodily functions and neural activity

functions: alcohol and barbiturates enhance gaba, reducing anxiety but impairing motor skills

alcohol

any beverage containing ethyl alcohol including beer, wine, and liquor

effects: binds to GABA to relax the drinker, depresses areas of the brain that control jugement and inhibition

sedative-hypnotic drugs

a drug used in low doses to reduce anxiety and in higher doses to help people sleep (barbituates and benzo)

barbituates (major tranquilizers)

addictive sedative-hypnotic drugs that reduce anxiety and help people sleep

effects: reduce a person’s level of excitement by attaching to GABA and helping GABA operate at those neurons

benzodiazepines (minor tranquilizers)

the most common group of anti-anxiety drugs, which include valium, xanax, and klonopin

effects: calm people by binding to receptors on neurons that receive GABA by increasing GABA activity at those neurons, relieve anxiety without making people as drowsy as other kinds of sedative hypnotics

opioids

opium or any of the drugs derived from opium, including morphine, heroin, and codeine

effects: depresses CNS, particularly the centers that help control emotion, attach to brain receptor sites that ordinarily receive endorphins

hallucinogens

alter perception and can cause visual or autditory hallucinations

function: affect serotonin or endocannabinoid systems, leading to distorted reality or mood shifts

LSD

powerful synthetic hallucinogen drug; also known as acid

effect: produces symptoms primarily by binding to some of the neurons that normally receive serotinin

cannabis AKA zaza AKA Mary Jane AKA marijuana AKA weed

drugs produced from the variety of the hemp plant Cannabis sativa

effect: cause a mix of hallucinogen, depressant, and stimulant effects

tolerance

they need to take more of a drug to achieve the same effect; you brain adjusts to, reducing the impact the drug’s affects over time

addiction

a compulsive craving for a substance despite harmful consequences; linked to changes in the drugs reward system, particularly dopamine

withdrawal

physical and psychological symptoms when stopping the drug; include nausea, anxiety, tremors, or intense cravings

substance use disorder

when drug use becomes uncontrollable and interferes with daily life; impacts behavior, relationships, and mental health

physiological effects

physical health problems such as liver problems from alcohol or lung damage from smoking

psychological effects

depression, anxiety, or paranoia can develop due to long-term drug use

biological influences

researchers believing that drug misuse may have biological causes

psychodynamic views

theorists believe people with substance use disorders have powerful dependency that can be traced back to early years

sociocultural influences

people are most likely to develop substance use disorders when they live under stressful socioeconomic conditions

behavioral views

operant conditioning may play a role in substance use disordesr; temporary reduction of tension produced by a drug has a rewarding effect, increasing the chance that the user will seek that reaction (rewarding feeling) again

cognitive views

theorists agree that rewards eventually produce an expectancy that substances will be rewarding and this expectation motivates people to increase drug use at times of tension