AP Pysch Unit 1 Pt 1

Nature vs. Nurture Debate

The longstanding debate over the relative contributions that genetics (nature) and environmental experiences (nurture) make to the development of psychological traits and behaviors.

Twin Studies

Research comparing identical (monozygotic) and fraternal (dizygotic) twins to isolate the effects of heredity versus environment on specific traits.

Family Studies

Research examining genetic similarity among family members to see if phenotypic traits cluster in families based on biological closeness.

Natural Selection

The evolutionary principle that traits promoting survival and reproduction are more likely to be passed on to succeeding generations.

Nervous System

The body's speedy, electrochemical communication network consisting of all the nerve cells of the central and peripheral nervous systems.

Central Nervous System (CNS)

The brain and spinal cord; responsible for processing sensory information and making decisions.

Peripheral Nervous System (PNS)

Sensory and motor neurons connecting the central nervous system to the rest of the body (limbs, organs, and skin).

Somatic Nervous System

A division of the peripheral nervous system that controls voluntary movements of skeletal muscles.

Autonomic Nervous System

A division of the peripheral nervous system controlling involuntary body functions (glands, smooth internal muscles, heart rate).

Sympathetic Nervous System

Branch of the autonomic nervous system that arouses the body, mobilizing energy in response to stress or danger (fight-or-flight).

Parasympathetic Nervous System

Branch of the autonomic nervous system that calms the body and conserves energy after a stressful situation (rest and digest).

Reflex Arc

An automatic, involuntary response to a stimulus where an interneuron in the spinal cord triggers a motor output before signals reach the brain.

Neuron

The basic building block and fundamental nerve cell of the nervous system, specialized for transmitting electrical and chemical messages.

Sensory Neurons (Afferent)

Neurons that carry incoming sensory information from sensory receptors to the brain and spinal cord.

Motor Neurons (Efferent)

Neurons that carry outgoing signals from the central nervous system to muscles and glands to produce action.

Interneurons

Neurons within the brain and spinal cord that communicate internally and intervene between sensory inputs and motor outputs.

Glial Cells

Cells in the nervous system that support, nourish, insulate, and protect neurons, and play a role in learning and memory.

Dendrites

Branching extensions of a neuron that receive incoming messages and conduct impulses toward the cell body.

Cell Body (Soma)

The neuron's life-support center that contains the nucleus and maintains cellular health.

Axon

The long fiber extension of a neuron that passes messages away from the soma toward other neurons, muscles, or glands.

Myelin Sheath

A fatty tissue layer segmentally encasing the axon that increases the speed of electrical impulse transmission.

Axon Terminals

The bulbous ends of an axon that release neurotransmitters across the synaptic gap to neighboring neurons.

Neural Firing

An electrochemical process in which an electrical impulse travels down an axon to communicate with other neurons.

Resting Potential

The electrical charge of an inactive neuron (~ -70 mV), with more negative ions inside the cell membrane than outside.

Depolarization

The influx of positively charged sodium ions into the neuron, making the internal charge less negative and triggering an action potential if threshold is reached.

Action Potential

A brief electrical charge/impulse that travels down the axon when a neuron fires.

Repolarization

The restoration of a negative membrane potential as potassium ions exit the cell following depolarization.

Refractory Period

A brief resting pause after a neuron has fired during which another action potential cannot be initiated until ionic balance is restored.

Threshold

The minimum level of stimulation required to trigger a neural impulse (~ -55 mV).

All-or-None Response

A neuron's reaction of either firing at full strength or not firing at all; strong stimuli increase firing frequency, not impulse size.

Synapse

The microscopic junction between the axon terminal of the sending neuron and the dendrite or cell body of the receiving neuron.

Reuptake

The reabsorption of excess neurotransmitters by the sending axon terminal after transmission of a signal.

Neurotransmitters vs. Hormones

Neurotransmitters travel fast across synaptic gaps in the nervous system; hormones travel slowly through the bloodstream via the endocrine system.

Serotonin

A neurotransmitter regulating mood, hunger, sleep, and arousal; deficits are strongly linked to clinical depression.

Dopamine

A neurotransmitter involved in voluntary movement, learning, attention, and pleasure/reward; excess linked to schizophrenia, deficit to Parkinson's.

Substance P

A neurotransmitter involved in sending pain signals to the central nervous system.

GABA (Gamma-Aminobutyric Acid)

The major inhibitory neurotransmitter in the brain; calms neural activity; deficit linked to anxiety and seizures.

Glutamate

The primary excitatory neurotransmitter in the central nervous system; critical for memory and learning; oversupply leads to excitotoxicity/migraines.

Norepinephrine

A neurotransmitter that controls alertness and physical arousal; active during fight-or-flight responses; deficit depresses mood.

Endorphins

Opiate-like neurotransmitters involved in natural pain relief and feelings of pleasure ('runner's high').

Acetylcholine (ACh)

A neurotransmitter enabling muscle action, learning, and memory; deterioration of ACh-producing neurons is linked to Alzheimer's disease.

Melatonin

A hormone produced by the pineal gland that regulates sleep-wake cycles and circadian rhythms.

Oxytocin

A hormone secreted by the pituitary gland that promotes social bonding, trust, empathy, and labor contractions during childbirth.

Ghrelin

A hunger-stimulating hormone secreted by an empty stomach that signals the hypothalamus that it is time to eat.

Leptin

A satiety hormone produced by fat cells that signals the brain to decrease appetite and increase metabolism.

Adrenaline (Epinephrine)

A hormone secreted by adrenal glands during stress that increases heart rate, blood pressure, and energy supplies in flight-or-fight response.

Parietal Lobe

Brain lobe located at the top rear of the head; contains the somatosensory cortex and processes touch, temperature, pressure, and spatial awareness.

Occipital Lobe

Cerebral lobe at the back of the head containing the primary visual cortex; processes visual stimuli.

Frontal Lobe

Front portion of cerebral cortex responsible for executive functions (decision making, planning, impulse control) and voluntary motor movement.

Temporal Lobe

Cerebral lobe located near the ears containing the primary auditory cortex; processes hearing, language comprehension, and memory encoding.

Brainstem

The oldest central core structure of the brain beginning where the spinal cord swells; controls automatic survival functions.

Medulla

The base of the brainstem controlling vital involuntary autonomic functions such as heart rate, breathing, and blood pressure.

Reticular Formation / RAS

A nerve network in the brainstem that plays an essential role in controlling arousal, alertness, and consciousness.

Cerebellum

The 'little brain' at the rear of the brainstem; coordinates voluntary movements, balance, posture, and implicit muscle memories.

Amygdala

Two lima-bean-sized neural clusters in the limbic system linked to emotion, particularly fear, aggression, and threat detection.

Thalamus

The brain's sensory switchboard located atop the brainstem; routes incoming sensory signals (except smell) to cerebral cortex regions.

Hypothalamus

Neural structure below the thalamus directing maintenance activities (eating, drinking, body temperature) and controlling the pituitary gland.

Limbic System

A donut-shaped neural system (including amygdala, hypothalamus, hippocampus) associated with emotions, motivation, and memory drive.

Broca's Area

Region in the left frontal lobe controlling muscle movements involved in speech production; damage causes expressive aphasia.

Wernicke's Area

Region in the left temporal lobe involved in language comprehension; damage causes receptive aphasia (meaningless speech).

Hippocampus

Limbic system structure responsible for processing and consolidating explicit, declarative long-term memories.

Cerebrum

The major, outer portion of the brain divided into two hemispheres; enables high-level cognitive function, perception, and voluntary action.

Pituitary Gland

The endocrine system's 'master gland,' regulated by the hypothalamus, secreting growth hormone and influencing other endocrine glands.

Corpus Callosum

A thick band of axon neural fibers connecting the left and right cerebral hemispheres, enabling communication between them.

Left vs. Right Hemisphere Lateralization

Left hemisphere specializes in language, logic, math, and analytical detail; Right hemisphere specializes in spatial tasks, facial recognition, and artistic creativity.

Split-Brain Condition

A condition resulting from surgery severing the corpus callosum; isolates the hemispheres, preventing direct communication between them.

Right Visual Field Processing

Visual information from the right visual field travels to the left cerebral hemisphere, allowing split-brain patients to name objects verbally.

Left Visual Field Processing

Visual information from the left visual field travels to the right cerebral hemisphere; split-brain patients cannot speak the word but can draw/point to it with their left hand.

Plasticity (Neuroplasticity)

The brain's ability to reorganize, form new neural pathways, or adapt following damage or through learning and experience.