intro to psych ch 3

neurons

cells that receive, process, and transmit information throughout the nervous system

cell body (soma)

contains nucleus and maintains cell

dendrite

RECEIVE signals from other neurons, carrying info towards cell body

axon

carries electrical signals (action potentials) AWAY from soma to other cells

myelin sheath

fatty layer around axons, protecting and increasing speed of action potentials

break points between clumps of myelin on the axon are called “nodes of Ranvier”

glial cells

non-neuronal nervous system cells that support and protect neurons; they can digest parts of dead neurons, provide support, and form the myelin insulating the axons for protection/efficiency

synapse

junction between neurons where info is transmitted (in beteween axon of neuron and dendrites or cell body of another)

terminal buttons

at ends of axon branches, store/release neurotransmitters into synapse when action potential arrives

sensory neurons (AFFRENT neurons)

neurons that carry info from external sensory receptors to CNS

receive info from external world, carry to brain and spinal cord

have specialized endings on their dendrites that receive signals for different senses

motor neurons (EFFERENT neurons)

neurons that carry commands from brain and spinal cord to outer muscles/glands, producing movement/response

long axons

interneurons

neurons mainly in CNS, processing info and connecting sensory with motor neurons or between interneurons

make up the majority of the nervous system

resting potential

electrical state when NOT firing
inside is NEGATIVE 70 mV

threshold = -55 mV

action potential

rapid, temporary change in voltage when a neuron reaches threshold and travels down axon (all-or-none)

refractory period

short period after action potential; neuron can’t fire again, or needs stronger stimulation

terminal buttons

structures at the ends of axon branches; store and release neurotransmitters into synapse when action potential arrives

neurotransmitters

receptors

specialized proteins that bind specific neurotransmitters

agonists

substances that increase or imitate a neurotransmitter’s effects

antagonists

substances that block or decrease a neurotransmitter’s effects

nervous system

body’s communication network of neurons and supporting cells

central nervous system

brain and spinal cord

peripheral nervous system

all nerves outside the brain and spinal cord

somatic nervous system

part of PNS: VOLUNTARY movement, carrying sensory info to CNS

autonomic nervous system

part of PNS: AUTOMATIC/INVOLUNTARY body functions

sympathetic nervous system

part of ANS: fight or flight response

parasympathetic nervous system

part of ANS: calming and conserving energy

spinal reflexes

fast automatic responses coordinated by spinal cord without waiting for brain (knee jerk reaction)

hindbrain

brain region involved in basic survival functions, movement and arousal (MPC - medulla, pons, cerebellum)

medulla

controls ESSENTIAL functions: breathing, heart rate, blood pressure

reticular formation

network involved in arousal, alertness, attention, sleep/wake states

cerebellum

helps control balance, coordination, movement, and motor learning

pons

regulates sleep, arousal, acts as info relayer between diff. brain regions

cerebral cortex

brain’s outer layer, responsible for higher-level functions like thought, language, voluntary movement

subcortical structures

brain structures below cerebral cortex involved in emotion, memory, motivation, movement

thalamus

SENSORY RELAY STATION, sending most sensory info to appropriate areas of cortex

hypothalamus

maintains homeostasis, regulating thirst, hunger, body temp, arousal, hormones

hippocampus

area of brain for forming new memories and learning

amygdala

area of brain for emotion, fear, threat detection, and emotional learning

basal ganglia

group of structures important for movement, habits, and learning actions

endocrine system

system of glands that release hormones into the bloodstream

pituitary gland

MASTER GLAND: endocrine gland controlled by hypothalamus, releases hormones affecting growth

corpus callosum

large bundle of nerve fibers connecting the hemispheres, allowing COMMUNICATION ACROSS HEMISPHERES

occipital lobe

responsible for vision and visual processing

parietal lobe

processes touch and body sensations, also spatial awareness

temporal lobe

important for HEARING, language, memory, and recognizing faces

frontal lobe

THINK/PLAN/ACT: involved in planning, decision-making, and voluntary movement

association areas

areas of cerebral cortex, integrating information, supporting complex functions like thinking, memory

mirror neurons

neurons that respond to another action

cultural neuroscience

study of how culture and the brain interact to influence behavior

gene

segment of dna containing info that can influence traits and biological functions

chromosomes

structures made of dna and proteins, humans have 23 pairs

epigenetics

study of changes in gene activity/expression without changing dna sequence itself, INFLUENCED BY ENVIRONMENTAL FACTORS

electroencephalograph (EEG)

graph = DEVICE using electrodes on scalp to record brain’s electrical activity

gram = RECORDING

graphy = PROCESS

order of neural communication

stimulus —> dendrite —> soma (cell body) —> axon —> terminal buttons —> neurotransmitter released across —> synapse —> receptor

depolarization

NA GOES IN, VOLTAGE GOES UP

repolarization

K GOES OUT, VOLTAGE GOES DOWN (rekout down)

CT/CAT scan

x-rays from different angles put together for physical structure

MRI

uses magnetic field and radio waves to create detailed image of structure

fMRI

measures changs in blood oxygenation to determine location of brain activity

PET scan

uses a tracer to measure metabolic or chemical activity in brain

TMS (transcranial magnetic stimulation)

delivers a magnetic pulse through the skull, deactivating neurons in the cerebral cortex temporarily, mimicking brain damage