AP Psych Terms 1.1 - 1.3 (55)

Nature–nurture issue

The debate over the relative contributions of genetic inheritance versus environmental factors in shaping behavior and mental processes.

Charles Darwin

The scientist who proposed the theory of evolution through natural selection.

Natural selection

The process by which inherited traits that enhance survival and reproduction become more common in a population over successive generations.

Evolutionary psychology

The study of how evolutionary principles and natural selection influence behavior, cognition, and mental processes.

Behavior genetics

The field of study focused on investigating the relative power and limits of genetic and environmental influences on behavior.

Mutation

A random change in a DNA sequence that serves as a primary source of genetic variation.

Environment

Every non-genetic external influence that acts upon an organism from prenatal development through life.

Heredity

The biological transmission of genetic traits and characteristics from parents to offspring.

Genes

The fundamental biochemical units of heredity that make up chromosomes and provide instructions to synthesize proteins.

Genome

The complete set of genetic instructions and DNA material contained within an organism.

Identical (monozygotic) twins

Twins who develop from a single fertilized egg that splits into two, resulting in genetically identical individuals.

Fraternal (dizygotic) twins

Twins who develop from two separate fertilized eggs, sharing approximately 50% of their genes like regular biological siblings.

Gene-environment interaction

The dynamic interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).

Epigenetics

The study of environmental influences on gene expression that occur without changes to the underlying DNA sequence.

Central nervous system (CNS)

The primary control network of the body consisting of the brain and spinal cord.

Peripheral nervous system (PNS)

The network of sensory and motor neurons that connects the central nervous system to the rest of the body.

Sensory (afferent) neurons

Neurons that carry incoming signals from sensory receptors inward toward the central nervous system.

Motor (efferent) neurons

Neurons that transmit outgoing signals from the central nervous system to muscles and glands.

Interneurons

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

Somatic nervous system

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

Autonomic nervous system (ANS)

The division of the peripheral nervous system that regulates involuntary bodily functions such as heart rate, digestion, and glandular activity.

Sympathetic nervous system

The branch of the autonomic nervous system that arouses the body and mobilizes energy during fight-or-flight scenarios.

Parasympathetic nervous system

The branch of the autonomic nervous system that calms the body and conserves energy during rest and digestion.

Reflex

A simple, automatic, and rapid response to a sensory stimulus, often mediated by a single spinal arc.

Neuron

The fundamental nerve cell that acts as the basic building block of the nervous system.

Dendrites

Branching extensions of a neuron that receive chemical signals from other cells and conduct them toward the cell body.

Axon

The single, elongated extension of a neuron that conducts electrical impulses away from the cell body toward terminal branches.

Myelin sheath

A fatty layer segmentally encasing axon fibers that insulates signals and increases the speed of neural impulse transmission.

Glial cells (glia)

Support cells in the nervous system that protect, nourish, and insulate neurons while maintaining synaptic connections.

Action potential

A brief electrical charge that travels down an axon when a neuron is activated.

Threshold

The minimum level of stimulation required to trigger a neural impulse.

Refractory period

A brief resting pause after a neuron has fired, during which another action potential cannot be generated until reset.

All-or-none response

The neural firing principle stating that an axon either fires at full strength or does not fire at all once threshold is reached.

Synapse

The microscopic gap across which neurotransmitters transmit signals from one neuron to another.

Neurotransmitters

Chemical messengers released from axon terminals that cross the synaptic gap to bind to receiving neuron receptors.

Reuptake

The process by which neurotransmitters remaining in the synaptic gap are reabsorbed by the sending neuron.

Endorphins

Opiate-like neurotransmitters linked to pain relief, stress reduction, and feelings of pleasure.

Agonist

A substance or drug that binds to a receptor site and mimics or enhances the effect of a neurotransmitter.

Antagonist

A substance or drug that binds to a receptor site and blocks or inhibits the effect of a neurotransmitter.

Endocrine system

The body's chemical communication system consisting of glands that secrete hormones directly into the bloodstream.

Hormones

Chemical messengers manufactured by endocrine glands that travel through the bloodstream to affect distant target organs.

Psychoactive drug

A chemical substance that alters perception, mood, consciousness, or behavior by acting on the central nervous system.

Tolerance

The diminished physiological or psychological effect of a drug after repeated exposure, requiring larger doses to produce the same effect.

Withdrawal

The uncomfortable physical and psychological symptoms that follow the sudden cessation of a habituated substance.

Barbiturates

A class of depressant drugs that reduce central nervous system activity, reducing anxiety but impairing memory and judgment.

Opioids

A category of drugs derived from or mimicking opium that depress neural activity, temporarily dulling pain and inducing euphoria.

Stimulants

A class of psychoactive drugs that excite neural activity and speed up body functions, increasing alertness and energy.

Hallucinogens

A class of psychoactive drugs that distort sensory perceptions and evoke vivid sensory images without external input.