Psych Mod 1.1-1.4

Psychology

Scientific study of behavior and mental processes.

Heredity

Passing of traits from parents to offspring through genes.

Environment

Every non-genetic influence: nutrition, culture, family, experiences.

Nature

The influence of biology and genes.

Nurture

The influence of experience and surroundings.

Interaction

Genes and environment work together; a genetic predisposition may only show up in certain environments.

Genes

DNA segments that code for proteins and traits.

Genome

The complete set of genetic instructions in an organism.

Evolutionary Perspective

Explains behaviors by how they helped ancestors survive and reproduce.

Natural Selection

Traits that improve survival and reproduction become more common over generations.

Mutations

Random gene changes; the raw material for evolution. May be harmful, neutral, or helpful.

Behavior Genetics

Studies how genes and environment influence individual differences.

Epigenetics

Environment switches genes on or off without changing the DNA sequence.

Eugenics

Discredited movement to “improve” humans through selective breeding.

Identical (Monozygotic) Twins

One fertilized egg splits; 100% shared genes.

Fraternal (Dizygotic) Twins

Two eggs; about 50% shared genes, like any siblings.

Twin studies

Identical twins more alike than fraternal twins (or alike when raised apart) suggests heredity.

Family studies

Compare relatives; closer genetic relatedness with more similarity suggests genetic influence.

Adoption studies

Adoptees resembling biological parents suggests heredity; resembling adoptive family suggests environment.

Nervous System

Body’s electrochemical communication network.

Central Nervous System (CNS)

Brain and spinal cord; the decision maker.

Peripheral Nervous System (PNS)

All nerves outside the CNS; connects CNS to body.

Nerves

Bundles of axons carrying information between the CNS and body.

Reflex

Automatic response to a stimulus, often routed through the spinal cord without the brain.

Somatic Nervous System

Voluntary control of skeletal muscles; carries sensory info to CNS.

Autonomic Nervous System

Controls involuntary functions (heart, digestion, glands).

Sympathetic Nervous System

Arouses the body; fight-or-flight.

Parasympathetic Nervous System

Calms the body; rest and digest.

Neurons

Nerve cells that receive, process, and transmit information.

Cell Body

Contains the nucleus; keeps the cell alive.

Dendrites

Branches that receive messages from other neurons.

Axon

Long fiber that sends the signal away from the cell body.

Myelin

Fatty insulation on axons that speeds up transmission.

Synapse

Tiny gap between the sending neuron’s terminal and the receiving neuron.

Glial Cells

Support, nourish, insulate, and clean up around neurons.

Sensory Neurons

Carry info from senses/body to the CNS.

Motor Neurons

Carry commands from the CNS to muscles and glands.

Interneurons

Within the CNS; connect sensory and motor neurons.

Reflex Arc

Sensory neuron → interneuron (spinal cord) → motor neuron.

Resting Potential

Neuron’s stable, polarized state (about −70 mV) when not firing.

Threshold

Level of stimulation needed to trigger an action potential.

Depolarization

Positive ions rush in, making the inside less negative and starting the action potential.

Action Potential

Brief electrical charge that travels down the axon.

All-or-Nothing Principle

A neuron either fires completely or not at all; stronger stimuli fire more often, not harder.

Refractory Period

Brief rest after firing during which the neuron cannot fire again.

Reuptake

Sending neuron reabsorbs leftover neurotransmitters from the synapse.

Multiple Sclerosis

Myelin deteriorates, slowing signals and impairing muscle control.

Myasthenia Gravis

Autoimmune attack on acetylcholine receptors; muscle weakness and fatigue.

Neurotransmitters

Chemical messengers that cross the synapse.

Excitatory Neurotransmitters

Make the receiving neuron more likely to fire.

Inhibitory Neurotransmitters

Make the receiving neuron less likely to fire.

Dopamine

Movement, reward, motivation. Too little: Parkinson’s. Too much: linked to schizophrenia.

Serotonin

Mood, hunger, sleep, arousal. Low levels linked to depression.

Norepinephrine

Alertness and arousal.

GABA

Main inhibitory transmitter. Too little: seizures, anxiety.

Glutamate

Main excitatory transmitter; learning and memory. Excess: seizures, migraines.

Substance P

Transmits pain signals.

Endorphins

Natural painkillers; pleasure.

Acetylcholine

Muscle action, learning, memory. Loss linked to Alzheimer’s.

Endocrine System

Glands that release hormones into the bloodstream; slower but longer-lasting than neural signals.

Hormones

Chemical messengers carried in the blood.

Adrenaline

Boosts heart rate and energy for fight-or-flight.

Ghrelin

Hunger signal.

Leptin

Fullness (satiety) signal.

Melatonin

Regulates sleep; secreted by the pineal gland.

Oxytocin

Bonding, trust, childbirth, nursing.

Psychoactive Drugs

Chemicals that change perception and mood by altering neural activity.

Substance Use Disorder

Continued use despite significant life problems.

Agonist

Mimics or enhances a neurotransmitter’s effect.

Antagonist

Blocks a neurotransmitter’s effect.

Reuptake Inhibitor

Blocks reuptake so more neurotransmitter stays in the synapse.

Stimulants

Speed up body functions: caffeine, cocaine, methamphetamines, ecstasy.

Depressants

Slow body functions: alcohol, barbiturates (sedatives), opioids.

Opioids

Opium and derivatives (heroin); mimic endorphins, reduce pain, cause euphoria.

Hallucinogens

Distort perception: LSD, marijuana (THC), ecstasy (also a stimulant).

Near-Death Experience

Altered state after close brush with death; resembles drug-induced hallucinations.

Tolerance

Need larger doses to get the same effect.

Withdrawal

Discomfort and distress after stopping a drug.

Addiction

Compulsive drug craving and use despite harmful consequences.

Biological Psychology

Studies links between biology and behavior.

Biopsychosocial Approach

Integrates biological, psychological, and social-cultural influences.

Levels of Analysis

Different scales for studying one phenomenon (biological, psychological, social-cultural).

EEG

Records electrical activity (brain waves) via scalp electrodes.

MEG

Measures magnetic fields from neural activity.

MRI

Magnetic fields and radio waves make detailed images of brain structure.

CT

X-ray slices combined into a structural image.

PET

Tracks radioactive glucose to show which areas are active.

fMRI

Tracks blood flow to show activity and structure together.

Lesions

Tissue destruction, natural or surgical, used to learn what an area does.

Brain Plasticity (Neuroplasticity)

Brain changes with experience and can reorganize after damage.

Brain Stem

Base of the brain; automatic survival functions.

Hindbrain

Medulla, pons, and cerebellum.

Midbrain

Relays sensory info; helps with orienting and movement.

Forebrain

Cerebral cortex, thalamus, hypothalamus, limbic system.

Medulla Oblongata

Controls heartbeat and breathing.

Reticular Activating System

Network through the brainstem controlling arousal and alertness.

Cerebellum

Balance, coordination, voluntary movement, procedural memory.

Limbic System

Emotion, memory, and drives.

Thalamus

Sensory switchboard; routes info to the cortex (not smell).

Hypothalamus

Hunger, thirst, temperature, sex drive; directs the pituitary.