PSYCH UNIT 1

nature

genes and biology

nurture

environment and experience

identical twins share __% of their genes?

100

fraternal twins share __% of their genes?

50 (same as regular siblings)

natural selection

some mutations help you survive, those traits are the ones that get passed on and become commonThis process gradually leads to the evolution of species over time.

evolutionary pyschology

explains behaviors as traits that helped our ancestors survive and reproduceand how these traits influence modern human behavior.

epigenetics

experiences can switch genes on or off without changing the DNA itself

heritability

how much of the variation in a trait in GROUPS are due to genes

operational definition

exactly how the variable is measured, very specific

Central Nervous System (CNS)

brain + spinal cord

Peripheral Nervous System (PNS)

every nerve outside them

Somatic (PNS)

voluntary skeletal muscles + sensory info coming in

Autonomic (PNS)

automatic; heart, breathing, digestion

Sympathetic (autonomic PNS)

arouses: fight or flight; racing heart, fast shallow breathing, pupils dilate, digestion slows

Parasympathetic (autonomic PNS)

calms: rest and digest, brings you back down

sensory (afferent) neurons

carry info INTO the CNS

motor (efferent) neurons

carry commands OUT

interneurons

connect them in the brain and spinal cord

reflex arc

pathway for response to a stimulus:

1. Receptor: Detects a physical or chemical change and turns it into an electrical signal.

2. Sensory Neuron: Carries the electrical signal from the receptor to the spinal cord or brainstem.

3. Integration Center: Processes the signal. In simple reflexes, this happens directly in the spinal cord (interneuron)

4. Motor Neuron: Carries the command signal away from the central nervous system toward the target.

5. Effector: The muscle or gland that carries out the physical response.

parts of a neuron

dendrites, soma, axon, myelin, myelin sheath, terminal buttons

dendrites

recieve signal

soma

processes signal

axon

carries the signal

myelin

speeds signal up

terminal buttons

release neurotransmitters into the synapse

resting potential

inside the neuron is NEGATIVE compared to the outside; neuron is polarized (loaded and ready)

action potential

when the neuron’s membrane reaches the threshold

depolarization

positive sodium ions rush in, the inside turns positive

refractory period

the short period of time after a neuron fires where it cannot fire again

all or none

concept where a neuron either fires or doesn’t; stronger stimulus means neuron fires more often, not hardere

excitatory

neurotransmitters push the next neuron towards firing

inhibitory

neurotransmitters that push the next neuron away from firing

gilal cells

supports, nourish, protect neurons

multiple scelrosis

when the myelin breaks down and the signals slow down

myasthenia gravis

immune system attack acetylecholine receptors, causing muscle weakness

reuptake

sending neuron reabsorbs leftover neurotransmitter from the synapse

acetylcholine

muscle contraction (alzheimer’s)

dopamine

want (parkisons)s

serotonin

mood (depression)

norepinephrine

arousal

GABA

inhibitory (anxiety)

glutamate

exicitatory (seizures)

endorphins

pain relief

substance P

pain signalsad

adrenaline (epinephrine)

flight or flighto

oxytocin

lovemel

melatonin

sleepty

laptin / ghrelin

full, hungry

pituitary gland

master gland, growth hormones

agonist

mimics/boosts neurotransmitter

an

antagonist

blocks neurotransmitter

stimulants

speeds up CNS (caffeine, nicotine, cocaine)

depressents

slows down CNS (alcohol, xanax)

opiods

relieve pain (heroin, morphine, fenta)

hallucinogens

create distorted vivid images (marijuana, shrooms)

reuptake inhibitor

blocks reabsorption so neurotransmitters stays longer (agonist)me

medulla

heart beath breahtingcr

cerebellum

balance

thalamus

send senses (not smell) to the cortex

hypothalamus

hungery, thirst, body temp

amygdala

fear, aggression

hippocampus

new memories

corpus callosum

connects two hemispheresf

frontal lobe

planning, decisions

parietal lobe

touch and sensation

occiptal lobe

vision

temporal lobe

hearing

broca’s area

produce speech

wernicke’s area

language proccessing

pons

sleepre

reticular

alertness

motor cortex

movement control

somatosensory cortec

touch

contralateral control

left hemisphere → right side of the body

split brain

cutting the corpus callosum so no more seizures, left eye cannot readpl

plasticity

brain can change and adjust to be better

transduction

conversion of physical energy into neural signals

absolute threshold

weakest stimulus you can detect 50% of the time (lower threshold, more sensitive)

difference threshold

smallest change you can notice

weber’s law

change has to be a constant proportion, not a fixed amount

sensory adaptation

stop noticing a constant, unchanging stimulus

sensory interaction

one sense affects another (like eating is taste and smell)

light’s path

cornea → pupil → lens → retina → optic nerve → thalamus → occipital lobe

rods

dim light, peripheral visioncon

cones

color and fine detail

blind spot

where optic nerve leaves the eye

trichromatic theory

red, green blue; explains color vision and blindnesso

opponent process theory

colors work in pairs and explains afterimages

amplitude

loudnessf

frequency

pitch

path

outer ear → eardrum → middle ear bones → cochlea → auditory nerve → thalamus → temporal lobe

high frequencies

harder to hear as we age

taste

sweet, sour, salty, bitter, savory

smell

skips the thalamus, goes straight to olfactory bubl

vestibular sense

balance and head position

kinesthesis

know where body parts are

gate control theory

spinal cord can block pain signals, rubbing an ouchie can help block

color vision deficiency

missing one cone type

prosopagnosia

face blindness