AP Psychology Unit 4

Heredity

the genetic transmission of traits from parents to offspring

Environmental factors

all non-genetic influences that shape behavior and development

Nature vs nurture

the debate over whether genetics or environment has a greater influence on behavior

Eugenics

a discredited movement that sought to improve human genetics through selective breeding

Evolutionary perspective

explains behavior as adaptations that helped ancestors survive and reproduce

Twin studies

research comparing identical and fraternal twins to assess genetic influence

Family studies

studies that examine how traits appear among biological relatives

Adoption studies

research comparing adopted individuals to their biological and adoptive families

Central nervous system

the brain and spinal cord, which process and coordinate information

Peripheral nervous system

all nerves outside the CNS that connect the brain and spinal cord to the body

Autonomic nervous system

controls involuntary bodily functions such as heart rate and digestion

Somatic nervous system

controls voluntary movement of skeletal muscles

Parasympathetic nervous system

calms the body and restores energy after stress

Sympathetic nervous system

prepares the body for action in stressful situations

Neurons

specialized cells that transmit information through electrical and chemical signals

Glial cells

cells that support, insulate, and protect neurons

Reflex arc

the neural pathway that controls automatic, involuntary responses

Sensory neurons

neurons that carry information from sensory receptors to the CNS

Motor neurons

neurons that transmit signals from the CNS to muscles or glands

Interneurons

neurons that process and relay information within the CNS

All-or-nothing principle

neurons fire completely or not at all once threshold is reached

Depolarization

the process by which a neuron’s charge becomes positive, triggering firing

Refractory period

the brief time after firing when a neuron cannot fire again

Resting potential

the neuron’s stable negative electrical charge when inactive

Reuptake

the reabsorption of neurotransmitters by the sending neuron

Threshold

the minimum level of stimulation required to fire a neuron

Multiple sclerosis

an autoimmune disease that damages myelin and slows neural signals

Myasthenia gravis

an autoimmune disorder causing muscle weakness and fatigue

Excitatory

increases the likelihood that a neuron will fire

Inhibitory

decreases the likelihood that a neuron will fire

Dopamine

a neurotransmitter involved in reward, motivation, and movement

Serotonin

a neurotransmitter involved in mood regulation and sleep

Norepinephrine

a neurotransmitter involved in alertness and arousal

Glutamate

the primary excitatory neurotransmitter in the brain

GABA

the primary inhibitory neurotransmitter that calms neural activity

Endorphins

neurotransmitters that reduce pain and increase pleasure

Substance P

a neurotransmitter involved in pain perception

Acetylcholine

a neurotransmitter involved in muscle movement and memory

Hormones

chemical messengers released into the bloodstream by glands

Adrenaline

a hormone that increases arousal and prepares the body for action

Leptin

a hormone that signals fullness and suppresses appetite

Ghrelin

a hormone that stimulates hunger

Melatonin

a hormone that regulates sleep-wake cycles

Oxytocin

a hormone involved in bonding, trust, and childbirth

Psychoactive drugs

substances that alter perception, mood, or behavior

Agonist

a substance that increases a neurotransmitter’s action

Antagonist

a substance that blocks or reduces a neurotransmitter’s action

Reuptake inhibitor

a drug that prevents neurotransmitter reabsorption

Stimulant

a drug that increases nervous system activity

Caffeine

a stimulant that increases alertness by blocking adenosine

Cocaine

a stimulant that increases dopamine by blocking reuptake

Depressant

a drug that slows nervous system activity

Alcohol

a depressant that reduces inhibitions and slows brain function

Hallucinogen

a drug that alters perception and sensory experience

Marijuana

a hallucinogen that affects memory, perception, and coordination

Opioid

a drug that reduces pain and produces euphoria

Heroin

an opioid that produces intense pleasure and high addiction risk

Tolerance

the need for increasing amounts of a substance to achieve the same effect

Addiction

compulsive substance use despite harmful consequences

Withdrawal

physical and psychological symptoms after stopping drug use

Brain stem

controls basic life functions like breathing and heart rate

Medulla

controls vital autonomic functions such as breathing

Reticular activating system

regulates alertness and arousal

Cerebellum

coordinates balance, movement, and motor learning

Cerebral cortex

the outer brain layer responsible for higher thinking

Left and right hemisphere

the two halves of the brain with specialized functions

Thalamus

the brain’s sensory relay station

Hypothalamus

regulates hunger, thirst, temperature, and hormones

Pituitary gland

the “master gland” controlling other endocrine glands

Hippocampus

involved in forming new memories

Amygdala

processes emotions, especially fear and aggression

Corpus callosum

connects the brain’s left and right hemispheres

Occipital lobe

processes visual information

Parietal lobe

processes touch and spatial awareness

Temporal lobe

processes hearing and language

Frontal lobe

involved in decision-making and impulse control

Somatosensory cortex

processes touch and body sensations

Prefrontal cortex

responsible for planning, judgment, and self-control

Motor cortex

controls voluntary muscle movements

Split brain research

studies of patients with severed corpus callosum

Broca’s area

controls speech production

Wernicke’s area

controls language comprehension

Contralateral organization

each brain hemisphere controls the opposite side of the body

Aphasia

impairment of language ability

Brain plasticity

the brain’s ability to change and reorganize

EEG

records electrical brain activity

fMRI

measures brain activity using blood flow

Lesioning

studying brain function by removing or damaging tissue

Mirror neuron

a neuron that fires when performing or observing an action

Pons

involved in sleep, arousal, and facial expressions

Synapse

the gap between neurons where communication occurs

Dendrites

receive incoming signals from other neurons

Axon

carries signals away from the neuron’s cell body

Axon terminal

releases neurotransmitters into the synapse

Terminal buttons

structures at axon ends that release neurotransmitters

Myelin sheath

fatty covering that speeds up neural transmission