psych u2

neuron

a nerve cell, the basic building block of the nervous system, dendrites listen and axons speak to carry info to other neurons, muscles, or glands

cell body

the part of a neuron that contains the nucleus, its life-support center that integrates incoming signals

dendrites

the bushy branching extensions that receive and integrate messages and conduct impulses toward the cell body

axon

the long segmented fiber that passes the message through its terminal branches to other neurons, muscles, or glands

myelin sheath

the fatty layer segmentally encasing some axons that makes transmission vastly faster as the impulse hops between nodes, when it degenerates you get multiple sclerosis

action potential

a brief electrical charge that travels down the axon, triggered when excitatory inputs push the cell past threshold, all-or-none and followed by a refractory period

resting potential

the positive-outside and negative-inside charge of a resting axon, a loaded battery waiting to fire

depolarization

when the membrane's charge difference collapses as positive ions flood in and the neuron fires

excitatory signals

chemical pushes that make a neuron more likely to fire, the accelerator

inhibitory signals

chemical pushes that make a neuron less likely to fire, the brake

threshold

the minimum level of stimulation needed to trigger a neural impulse

refractory period

the brief pause after firing when the axon resets and cannot fire again, even a huge stimulus will not work

all-or-none response

a neuron either fires at full strength or not at all, stronger stimuli just make it fire more often

synapse

the junction between the sending neuron's axon tip and the receiving neuron's dendrite or cell body where communication jumps

neurotransmitters

chemical messengers released into the gap that bind to receptors on the next neuron and decide if it fires

reuptake

the sending neuron reabsorbing excess transmitter after release to shut the signal off, antidepressants often block this

acetylcholine (ACh)

enables muscle action, learning, and memory, its neurons deteriorate in Alzheimer's

dopamine

influences movement, learning, attention, and emotion, too little links to Parkinson's tremors, too much to schizophrenia

serotonin

affects mood, hunger, sleep, and arousal, low levels link to depression

norepinephrine

helps control alertness and arousal, low levels can depress mood

GABA

the major inhibitory transmitter that calms the brain, low GABA links to seizures, tremors, and insomnia

glutamate

the major excitatory transmitter involved in memory, too much can cause migraines or seizures

endorphins

your natural opioids, morphine within, linked to pain control and pleasure, they explain runner's high

agonist

a molecule that boosts a neurotransmitter by increasing release, blocking reuptake, or mimicking it at receptors

antagonist

a molecule that blocks a neurotransmitter by reducing release or occupying its receptors

afferent neurons

sensory neurons that carry information from receptors toward the brain and spinal cord, afferent arrives

efferent neurons

motor neurons that carry commands away from the central nervous system to muscles and glands, efferent exits

interneurons

neurons inside the brain and spinal cord that process information between sensory and motor neurons

reflex arc

a fast automatic path where sensory input, interneuron, and motor output all happen in the spinal cord, no brain needed, like pulling your hand off a hot iron

central nervous system

the brain and spinal cord, the decision center

peripheral nervous system

all the nerves outside the brain and spinal cord that connect the body to the central nervous system

somatic nervous system

the division that controls voluntary skeletal muscle movement and carries sensory info

autonomic nervous system

the division that controls involuntary functions like digestion, heart rate, and breathing

sympathetic nervous system

the arousing fight-or-flight branch, dilates pupils, races the heart, sweats, slows digestion

parasympathetic nervous system

the calming rest-and-digest branch, slows heart rate, constricts pupils, promotes digestion

spinal cord

the highway of fibers to and from the brain that also runs simple reflexes on its own

endocrine system

the slow chemical system of glands that secrete hormones into the bloodstream to affect the brain and body

hormones

chemical messengers made by endocrine glands that travel in blood and affect distant tissues including the brain

adrenal glands

glands on top of the kidneys that release epinephrine and norepinephrine in emergencies

epinephrine and norepinephrine

stress hormones that raise heart rate, blood pressure, and blood sugar to power fight-or-flight

fight-or-flight response

the emergency surge of energy in a threatening situation, driven by adrenal hormones

pituitary gland

the pea-sized master gland in the brain core, controlled by the hypothalamus, releases growth hormone and oxytocin and directs other glands

hypothalamus

the brain area that controls the pituitary, governs hunger, thirst, temperature, and emotion, and triggers stress responses

oxytocin

enables orgasm, labor contractions, and nursing milk flow and promotes bonding and trust

cortisol

the stress hormone that raises blood sugar, measured in saliva as a stress marker

psychoactive drug

any chemical that alters the brain to change perceptions and moods

substance use disorder

continued use despite major life disruption, marked by diminished control, social problems, hazardous use, and tolerance or withdrawal

tolerance

needing larger and larger doses over time to get the same effect because the brain has adapted

withdrawal

discomfort and distress after stopping an addictive drug as the brain rebounds, usually the opposite of the drug's effect

addiction

compulsive use that continues despite harmful consequences

neuroadaptation

the brain offsetting a drug's effect by adjusting its chemistry, which is what drives tolerance

depressants

drugs that reduce neural activity and slow body functions, includes alcohol, barbiturates, and opioids

stimulants

drugs that excite neural activity and speed up the body, raise heart rate, breathing, and energy, highly addictive

hallucinogens

psychedelic drugs that distort perceptions and create sensory images without input by acting at synapses

phrenology

Franz Gall's debunked idea that skull bumps reveal mental abilities and character

localization of function

the principle that different brain regions serve specific functions, supported by lesion and stimulation studies

biological psychology

the study of links between biology and psychological processes, also called biopsychology or behavioral neuroscience

biopsychosocial approach

the view that biology, psychology, and social-cultural factors all interact to shape behavior

levels of analysis

the complementary lenses from biological to social-cultural for explaining any phenomenon

neuroplasticity

the brain's ability to reorganize and build new pathways with experience or after damage, strongest in childhood but lifelong

lesion

destruction of tissue from injury, disease, or surgery, also made experimentally to study function loss

neurogenesis

the formation of new neurons, can happen in some adult regions like the hippocampus

EEG

electrodes on the scalp record the brain's electrical waves sweeping across its surface, shows function over time

CT scan

combines X-rays from many angles into a computer composite slice showing brain anatomy

PET scan

tracks where radioactive glucose goes to show which brain areas are most active during a task

MRI

uses magnetic fields and radio waves to make detailed images of soft tissue and show brain anatomy

fMRI

compares successive MRI scans to track blood flow and oxygen, revealing brain function as well as structure

brainstem

the oldest central core where the spinal cord swells into the skull, handles automatic survival functions

medulla

the base of the brainstem that controls heartbeat and breathing, damage here is often fatal

pons

just above the medulla, helps coordinate movement and regulate sleep, waking, and dreaming

thalamus

the forebrain sensory switchboard on top of the brainstem that relays all senses except smell to the cortex

reticular formation

the arousal filter network running through the brainstem to the thalamus that sifts incoming info and governs alertness, damage can cause deep coma

cerebellum

the little brain behind the brainstem that coordinates voluntary movement, balance, and nonverbal learning and memory

basal ganglia

deep structures that with the cerebellum control motor movement and skill learning

limbic system

the system under the cortex including amygdala, hippocampus, and hypothalamus that drives emotion, memory, and motivation

amygdala

two lima-bean clusters that drive fear and aggression, stimulate it and you get aggression, damage it and you cannot read fear in faces

hippocampus

the curved limbic center that processes explicit memories and spatial maps for storage, damage means no new memories

cerebral cortex

the wrinkled outer fabric of interconnected cells covering the hemispheres, the ultimate control and information center

lobes

the four divisions per hemisphere separated by deep fissures, frontal, parietal, occipital, temporal

frontal lobes

behind the forehead, handle speech, muscle movement, planning, judgment, and impulse control, site of Phineas Gage injury

parietal lobes

top and rear, register touch and body position in the somatosensory cortex and support spatial attention

occipital lobes

at the back, contain the visual cortex that receives input from the eyes, damage here causes cortical blindness even with healthy eyes

temporal lobes

above the ears, house auditory cortex and language areas that process sound and meaning

motor cortex

the strip at the rear of the frontal lobes that controls voluntary movements on the opposite side of the body, more cortex devoted to fingers and mouth

somatosensory cortex

the strip at the front of the parietal lobes that maps touch and body position from the opposite side, left arm sensation lives in the right hemisphere

association areas

the vast cortical areas beyond primary motor and sensory zones that handle learning, remembering, thinking, and speaking

prefrontal cortex

the front-most association area for judgment, planning, social behavior, and new memories

visual cortex

in the occipital lobes, receives direct input from the eyes and maps the visual field

auditory cortex

in the temporal lobes, receives input primarily from the opposite ear

Broca's area

left frontal language area that controls speech production, damage means you understand speech but cannot produce it fluently

Wernicke's area

left temporal language area that handles comprehension, damage means you speak fluently but cannot understand what is said to you

contralateral hemispheric organization

most nerves from each side of the brain cross to control and sense the opposite side of the body

corpus callosum

the huge band of axon fibers connecting the two hemispheres so they share info

split brain

when the corpus callosum is cut, the two hemispheres work independently, studied by Sperry, Myers, and Gazzaniga

lateralization

the two hemispheres specialize, left more verbal, literal, and analytical, right more visual, spatial, and inferential

hemispatial neglect

inattention to one side of space, usually the left, caused by damage to the right parietal lobe

Phineas Gage

the 1848 railroad worker whose iron rod through the frontal lobes removed his inhibitions and showed the frontal lobes guide personality

consciousness

your subjective awareness of yourself and your environment right now

dual processing

information runs on two tracks at once, a conscious deliberate high road and an unconscious automatic low road

blindsight

responding accurately to something you say you cannot see because the visual action track still processes it