AP Psychology Unit One: Biological Bases of Behavior

Comprehensive vocabulary flashcards covering the biological bases of behavior, including genetics, neural transmission, the endocrine system, brain anatomy, psychoactive drugs, and states of consciousness and sleep.

Psychology

The science of behavior and mental processes.

Nature versus Nurture Issue

The longstanding psychological debate arguing whether genetic inheritance (nature) or environmental factors (nurture) play a greater role in shaping psychological traits and behaviors.

Natural Selection

The evolutionary principle that inherited traits that better enable an organism to survive and reproduce in a particular environment will, in competition with other trait variations, most likely be passed on to succeeding generations.

Adaptation

The process by which a species becomes fitted to its environment through the mechanism of natural selection.

Mutation

A random error in gene replication that leads to a genetic change.

Behavior Geneticists

Researchers who explore the genetic and environmental roots of human differences and study the relative power and limits of genetic and environmental influences on behavior.

Evolutionary Psychologists

Psychologists who focus on what makes humans alike by exploring universal behaviors and physical or psychological predispositions using principles of natural selection.

Heredity

The genetic transfer of characteristics from biological parents to offspring.

Environment

Every nongenetic influence, ranging from prenatal nutrition to the people, culture, and objects around us.

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

DNA (Deoxyribonucleic Acid)

A complex molecule containing the genetic information that makes up chromosomes.

Genes

The biochemical units of heredity that make up chromosomes; segments of DNA capable of synthesizing proteins.

Genome

The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes.

Molecular Genetics

The subfield of biology that studies the molecular structure and function of individual genes.

Heritability

The proportion of variation among individuals within a specific group that can be attributed to genetic differences.

Identical (Monozygotic) Twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

Fraternal (Dizygotic) Twins

Twins who develop from separate fertilized eggs simultaneously; they are no closer genetically than ordinary brothers and sisters, sharing roughly $50\%$ of their genes.

Epigenetics

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

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 primary division of the nervous system composed exclusively of the brain and spinal cord.

Peripheral Nervous System (PNS)

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

Autonomic Nervous System (ANS)

The division of the peripheral nervous system that controls involuntary, self-regulated activity of internal organs and glands.

Sympathetic Nervous System

The branch of the autonomic nervous system that arouses the body to mobilize energy in stressful situations (the fight-or-flight response), accelerating heart rate, dilating pupils, and inhibiting digestion.

Parasympathetic Nervous System

The branch of the autonomic nervous system that calms the body to conserve energy (the rest-and-digest response), slowing heart rate, constricting pupils, and stimulating digestion to return the body to homeostasis.

Somatic Nervous System

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

Afferent Nerves

Sensory neurons that carry incoming information from sensory receptors toward the brain and spinal cord.

Efferent Nerves

Motor neurons that carry outgoing instructions from the brain and spinal cord to muscles and glands.

Interneurons

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

Reflex

A simple, automatic inborn response to a sensory stimulus, often mediated at the level of the spinal cord without brain involvement.

Enteric Nervous System

The division of the nervous system that directly regulates and controls the gastrointestinal tract, pancreas, and gallbladder, containing sensory neurons, motor neurons, and interneurons.

Neuron

A nerve cell; the fundamental building block of the nervous system.

Soma

The cell body of a neuron that contains the nucleus and DNA, maintaining life-supporting cellular functions.

Dendrites

The branching extensions of a neuron that receive chemical messages from adjacent cells and conduct impulses toward the cell body.

Axon

The lengthy neuron extension that conducts electrical impulses away from the cell body toward axon terminals.

Myelin Sheath

A fatty tissue layer segmentally encasing the axon of many neurons, which insulates and protects the axon while dramatically increasing transmission speed.

Axon Terminals

Knob-like endings at the tip of an axon, also known as terminal buttons, that release neurotransmitters into the synapse to communicate with the next neuron.

Schwann Cells

Specialized cells in the peripheral nervous system that wrap around axons to produce the myelin sheath.

Nodes of Ranvier

Microscopic unmyelinated gaps along an axon between adjacent Schwann cells where ion exchange occurs to facilitate rapid nerve impulses.

Glial Cells

Supportive cells in the nervous system (glia) that protect, nourish, and insulate neurons, functioning like 'worker bees' to the neuronal 'queen bees'.

Resting Potential

The baseline electrical state of an inactive neuron when it maintains a slightly negative internal charge (approximately $-70\,\text{mV}$) and polarized ions.

Threshold

The minimum level of stimulation required to trigger a neural impulse, typically around $-55\,\text{mV}$.

Action Potential

A brief electrical charge that travels down an axon, produced by the depolarization and rapid exchange of ions across the cell membrane.

All-or-Nothing Law

The principle that a neuron either fires completely at full strength or does not fire at all, with the strength of firing remaining independent of the stimulus intensity once threshold is met.

Refractory Period

A brief resting pause that occurs after a neuron has fired, during which subsequent action potentials cannot be triggered until ions are repolarized back to resting potential.

Synapse

The junction between the axon tip of a sending neuron and the dendrite or cell body of a receiving neuron, containing a minute gap known as the synaptic cleft.

Neurotransmitters

Chemical messengers that cross the synaptic gap between neurons to bind to specific receptor sites on receiving cells.

Reuptake

A neurotransmitter's reabsorption by the sending neuron's axon terminals after it has been released into the synaptic cleft.

Acetylcholine (ACh)

A neurotransmitter that enables muscle action, learning, and memory; an undersupply is linked to Alzheimer's disease, and an oversupply causes paralysis (as seen with Black Widow spider venom).

Dopamine

A neurotransmitter that influences voluntary movement, learning, attention, and emotion; undersupply is linked to Parkinson's disease, while oversupply is linked to schizophrenia.

Serotonin

A neurotransmitter that affects mood, hunger, sleep, and arousal; an undersupply is linked to depression.

Norepinephrine

A neurotransmitter that helps control alertness and physical arousal; an undersupply is linked to depression, while an oversupply is associated with anxiety and mania.

GABA (Gamma-Aminobutyric Acid)

A major inhibitory neurotransmitter serving as a natural tranquilizer involved in calming neural activity; undersupply is linked to seizures, tremors, and insomnia.

Glutamate

A major excitatory neurotransmitter involved in memory and learning; undersupply is linked to concentration problems, whereas oversupply overstimulates the brain, causing seizures and migraines.

Endorphins

Opiate-like neurotransmitters that influence the perception of pain and pleasure; undersupply is linked to depression, while oversupply can leave an individual wired and anxious.

Agonist

A molecule that increases or mimics a neurotransmitter's action by binding to receptor sites and stimulating a neural response (e.g., morphine mimicking endorphins).

Antagonist

A molecule that inhibits or blocks a neurotransmitter's action by binding to receptor sites without stimulating them (e.g., curare blocking acetylcholine receptors to cause paralysis).

Reuptake Inhibitors

Chemical substances or drugs that block the reabsorption of neurotransmitters by sending neurons, leaving them in the synaptic gap longer to stimulate receptors.

Endocrine System

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

Hormones

Chemical messengers manufactured by endocrine glands that travel through the bloodstream and affect other tissues.

Adrenal Glands

A pair of endocrine glands situated just above the kidneys that secrete adrenaline (epinephrine), noradrenaline, and cortisol to trigger the fight-or-flight response.

Pituitary Gland

The endocrine system's 'master gland', located at the base of the brain and controlled by the hypothalamus, which secretes growth hormone, oxytocin, and hormones that regulate other glands.

Pineal Gland

An endocrine gland in the brain that secretes melatonin to regulate the sleep-wake cycle.

Psychoactive Drugs

Chemical substances that alter perceptions, consciousness, and moods by disrupting neurotransmitter activity.

Substance Use Disorder

A clinical disorder characterized by continued substance craving and use despite significant life disruption, hazardous use, and/or physical risk.

Tolerance

The diminishing psychoactive effect resulting from regular use of the same dose of a drug, requiring users to take larger amounts to achieve the initial effect.

Withdrawal

The discomfort, distress, and painful physiological symptoms experienced when the body re-adjusts after discontinuing an addictive drug.

Depressants

A class of psychoactive drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity, slow down body processes, and promote relaxation.

Stimulants

A class of psychoactive drugs (such as caffeine, nicotine, cocaine, and methamphetamine) that excite neural activity, speed up body processes, and increase alertness.

Hallucinogens

A class of psychoactive drugs (such as LSD, marijuana, and MDMA) that distort perceptions and evoke vivid sensory images in the absence of actual sensory input.

Biopsychosocial Approach

An integrated psychological perspective evaluating human behavior and mental processes through the combined interaction of biological, psychological, and social-cultural factors.

Neuroplasticity

The brain's lifelong ability to adapt, reorganize, and build new neural pathways in response to experience, learning, or damage.

Neurogenesis

The biological process by which new neurons are generated in the brain.

Trephination

A prehistoric medical practice involving drilling holes into the skull, historically believed to release trapped evil spirits.

Lesion

Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue used to study function.

Electroencephalogram (EEG)

A diagnostic recording tool using electrodes placed on the scalp to measure continuous electrical waves of neural activity sweeping across the brain's surface.

Magnetoencephalography (MEG)

A brain imaging technique that uses a head coil to measure the magnetic fields generated by the brain's natural electrical currents.

Computed Tomography (CT) Scan

A brain imaging procedure where X-rays taken from multiple angles generate cross-sectional images of the head to locate structural damage.

Positron Emission Tomography (PET) Scan

A functional brain-imaging technique that tracks the consumption of a temporarily radioactive form of glucose to detect metabolic activity while a subject performs a task.

Magnetic Resonance Imaging (MRI)

A structural imaging technique that uses magnetic fields and radio waves to generate high-resolution computer images of soft tissue and brain anatomy.

Functional MRI (fMRI)

A brain imaging technique that reveals brain function and activity by comparing successive MRI scans to detect changes in blood flow and oxygenation.

Brainstem

The oldest and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival mechanisms.

Medulla

The base of the brainstem that controls involuntary life-support functions, including heartbeat and breathing.

Pons

The brainstem structure lying above the medulla that helps coordinate movements, controls respiration, connects brain regions, and regulates sleep and REM dreaming.

Reticular Formation

A nerve network traveling through the brainstem into the thalamus that plays a vital role in controlling arousal and wakefulness.

Thalamus

The brain's sensory switchboard, located atop the brainstem, which directs messages to sensory receiving areas in the cerebral cortex for all senses except smell.

Cerebellum

The 'little brain' located at the rear of the brainstem that processes sensory input, coordinates voluntary movement and balance, and supports nonverbal learning and memory.

Limbic System

A doughnut-shaped neural system located below the cerebral hemispheres (including the amygdala, hippocampus, and hypothalamus) associated with emotions, memories, and basic drives.

Amygdala

Two lima-bean-sized neural clusters in the limbic system linked directly to primal survival emotions, particularly fear and aggression.

Hippocampus

A neural structure in the limbic system essential for processing and consolidating explicit, conscious memories of facts and events for long-term storage.

Hypothalamus

A limbic structure lying below the thalamus that directs maintenance behaviors (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Corpus Callosum

A broad band of nerve fibers connecting the left and right cerebral hemispheres, allowing continuous communication between them.

Cerebral Cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres, serving as the body's ultimate control and information-processing center.

Frontal Lobes

The portion of the cerebral cortex lying behind the forehead, responsible for executive functions including planning, abstract thought, judgment, personality, and motor control.

Motor Cortex

An area located at the rear of the frontal lobes that controls voluntary movements by transmitting motor commands to muscles.

Broca's Area

A specialized region situated in the left frontal lobe that controls the physical muscle movements required for speech production.

Broca's Aphasia

A language impairment caused by damage to Broca's area, characterized by severe difficulty in producing fluent, articulate speech.

Parietal Lobes

The portion of the cerebral cortex lying at the top of the head toward the rear, receiving and processing sensory input for touch, pain, temperature, and body position.

Somatosensory Cortex

A region located at the front of the parietal lobes that registers and processes tactile sensations and body movement inputs from corresponding body regions.

Temporal Lobes

The portion of the cerebral cortex lying roughly above the ears, containing primary auditory processing areas and structures essential for memory and language comprehension.

Wernicke's Area

A brain area located in the left temporal lobe involved in language interpretation and comprehension.