AP Psychology Unit 1: Biological Bases of Behavior Terms List

Comprehensive vocabulary flashcards for Unit 1: Biological Bases of Behavior covering heredity and environment, the nervous system, and the neuron and neural firing.

Heredity

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

Nature

The genetic, biological, and innate influences that shape human development and behavior.

Nurture

The environmental, social, cultural, and experiential factors that influence human development and behavior.

Genetic predisposition

An increased biological likelihood or susceptibility to developing a particular trait, disease, or behavioral pattern based on inherited genes.

Evolutionary perspective

A psychological approach focusing on how natural selection, adaptation, and inherited traits have shaped modern human behavior and mental processes.

Natural selection

The evolutionary principle that inherited trait variations contributing to survival and reproduction are more likely to be passed on to future generations.

Eugenics

A historical movement and set of practices aimed at improving the genetic qualities of the human species, often through selective breeding or forced sterilization.

Twin studies

Behavioral genetic research comparing identical (monozygotic) and fraternal (dizygotic) twins to assess the relative influences of heredity versus environment.

Family studies

Research examining blood relatives across generations to determine the degree of hereditary transmission of specific traits or psychological disorders.

Adoption studies

Research comparing adopted individuals with their biological and adoptive relatives to disentangle the effects of genetic inheritance from rearing environment.

Central nervous system (brain and spinal cord)

The complex of nerve tissues consisting of the brain and spinal cord that controls, integrates, and coordinates bodily activities.

Peripheral nervous system

The division of the nervous system consisting of all nerves outside the central nervous system, connecting the brain and spinal cord to limbs and organs.

Autonomic nervous system

The division of the peripheral nervous system responsible for regulating involuntary physiological processes such as heart rate, digestion, and respiration.

Sympathetic nervous system

The branch of the autonomic nervous system that arouses the body and mobilizes energy in stressful situations, initiating the fight-or-flight response.

Parasympathetic nervous system

The branch of the autonomic nervous system that calms the body, conserves energy, and supports routine rest-and-digest functions.

Somatic nervous system

The division of the peripheral nervous system that controls voluntary movements of skeletal muscles and conveys sensory information to the central nervous system.

Neurons

Specialized nerve cells that serve as the basic functional building blocks of the nervous system, transmitting electrical and chemical messages.

Glial cells

Non-neuronal cells in the nervous system that provide structural support, nutrition, protection, and myelin insulation for neurons.

Reflex arc

A neural pathway mediating a rapid, involuntary reflex action directly through the spinal cord without requiring prior input from the brain.

Sensory neurons

Afferent neurons that transmit incoming sensory information from sensory receptors toward the central nervous system.

Motor neurons

Efferent neurons that carry outgoing signals from the central nervous system to effector organs such as muscles and glands.

Interneurons

Neurons located entirely within the central nervous system that communicate between and process information from sensory and motor neurons.

Neural transmission

The electrochemical process through which nerve impulses travel along a neuron and are communicated across synapses to target cells.

Action potential

A brief electrical impulse that travels down the axon of a neuron when stimulated past its firing threshold.

All-or-nothing principle

The rule stating that a neuron fires at full strength or does not fire at all once the stimulation threshold is reached, with no graded intensity of a single impulse.

Depolarization

The change in electrical charge across a neural membrane toward zero or a positive charge, caused by an influx of positively charged ions.

Refractory period

A brief period of time following an action potential during which a neuron cannot generate another action potential until it resets to its resting state.

Resting potential

The electrical polarization of an inactive neuron when it is not firing an impulse, typically measured at approximately $-70\,\text{mV}$.

Reuptake

The reabsorption of excess neurotransmitter molecules back into the presynaptic neuron after release into the synaptic cleft.

Threshold

The minimum level of stimulation required to trigger an action potential in a neuron.

Multiple sclerosis

An autoimmune disorder in which the immune system damages the myelin sheath of nerve cells in the central nervous system, disrupting neural transmission.

Myasthenia gravis

A chronic autoimmune neuromuscular disease where antibodies block or destroy acetylcholine receptors, leading to skeletal muscle weakness and fatigue.

Excitatory neurotransmitters

Chemical messengers that depolarize the postsynaptic membrane, increasing the likelihood that the receiving neuron will generate an action potential.

Inhibitory neurotransmitters

Chemical messengers that hyperpolarize the postsynaptic membrane, decreasing the likelihood that the receiving neuron will fire an action potential.

Dopamine

A neurotransmitter that influences voluntary movement, reward-motivated behavior, attention, learning, and emotional arousal.

Serotonin

A neurotransmitter primarily involved in the regulation of mood, sleep, appetite, arousal, and emotional states.

Norepinephrine

A neurotransmitter and hormone that plays a critical role in vigilance, physical arousal, alertness, and the fight-or-flight stress response.