Unit 1A: Biological Bases of Behavior - The Nervous System and the Brain

Comprehensive practice flashcards covering AP Psychology Unit 1A: Biological Bases of Behavior, detailing neuroanatomy, neural communication, neurotransmitters, psychoactive substances, brain structures, and cortical functions.

Nature vs. Nurture

The psychological debate examining whether human behavior, traits, and development are primarily influenced by biological and genetic factors (nature) or environmental influences and life experiences (nurture).

Heredity

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

Evolutionary Psychology

The branch of psychology that investigates how natural selection has shaped behavioral tendencies, cognitive processes, and psychological adaptations over time.

Natural Selection

The evolutionary principle that inherited physical and behavioral variations that enhance an organism's ability to survive and reproduce are most likely to be passed on to future generations.

Eugenics

A historical social and scientific movement in the late 19th and early 20th centuries that attempted to alter and 'improve' the genetic composition of human populations through selective breeding and compulsory sterilization.

Central Nervous System (CNS)

The primary control center of the body comprising the brain and the spinal cord.

Peripheral Nervous System (PNS)

The network of nerves outside the central nervous system that connects the brain and spinal cord to sensory receptors, muscles, and glands throughout the body.

Somatic Nervous System

A major division of the peripheral nervous system that governs the voluntary movement of skeletal muscles and relays sensory information to the central nervous system.

Autonomic Nervous System

The division of the peripheral nervous system that regulates involuntary bodily processes, including heartbeat, respiration, digestion, and glandular activities.

Sympathetic Nervous System

The branch of the autonomic nervous system that mobilizes energy and physiological arousal in response to perceived stress or danger, initiating the 'fight-or-flight' response.

Parasympathetic Nervous System

The branch of the autonomic nervous system responsible for calming the body and conserving energy, lowering heart rate and promoting digestion to maintain homeostatic balance.

Glial Cells (Glia)

Non-neuronal support cells in the nervous system that insulate, nourish, and protect neurons, clean up metabolic waste, and assist in signal transmission.

Neuron

The fundamental structural and functional cellular unit of the nervous system, specialized for receiving, integrating, and transmitting electrochemical impulses.

Sensory (Afferent) Neurons

Specialized neurons that detect sensory stimuli from the environment or bodily tissues and carry incoming neural impulses toward the central nervous system.

Motor (Efferent) Neurons

Neurons that convey outgoing motor commands from the brain and spinal cord to muscles and glands to trigger physical actions.

Interneurons

Neurons located entirely within the brain and spinal cord that process, interpret, and relay signals between sensory neurons and motor neurons.

Reflex Arc

A direct neural pathway controlling an involuntary, automatic response to a stimulus, typically operating through a sensory neuron, an interneuron, and a motor neuron in the spinal cord without requiring prior conscious processing by the brain.

Depolarization

The neural event where positive ions enter the axon membrane, reducing negative charge and driving the membrane potential toward the threshold required to fire an action potential.

All-or-None Principle

The neural law stating that a neuron either fires completely with full and consistent electrical intensity or does not fire at all once its excitation threshold is attained.

Refractory Period

The mandatory recovery interval following an electrical impulse during which a neuron reestablishes its resting potential and cannot immediately generate another action potential.

Threshold

The minimum level of electrical stimulation required by a neuron to trigger an all-or-none action potential.

Reuptake

The biological process in which unabsorbed neurotransmitters lingering in the synaptic cleft are reabsorbed by the presynaptic terminal buttons for recycling and reuse.

Myelin Sheath

A protective fatty tissue covering that encases segments of the axon, drastically accelerating the conduction velocity of neural impulses as they jump between nodes of Ranvier.

Multiple Sclerosis (MS)

A chronic autoimmune disorder in which the immune system degrades the myelin sheath of nerves in the central nervous system, hindering neural communication between the brain and body.

Myasthenia Gravis

An autoimmune illness marked by progressive skeletal muscle fatigue and weakness, caused by immune antibodies binding to and disabling acetylcholine receptors at neuromuscular synapses.

Neurotransmitters

Endogenous chemical messengers synthesized by neurons and released across synaptic gaps to excite or inhibit post-synaptic target cells.

Acetylcholine ($ACh$)

A vital neurotransmitter that controls voluntary muscle contraction and plays key roles in memory formation, attention, and cognitive learning.

Dopamine

A neurotransmitter regulating pleasure, reward reinforcement, motivation, and motor coordination; an undersupply is linked to Parkinson's disease, while excess activity is associated with schizophrenia.

Serotonin

A monoamine neurotransmitter responsible for modulating mood, hunger, sleep cycles, and arousal; insufficient levels are implicated in major depressive disorder.

GABA (Gamma-Aminobutyric Acid)

The primary inhibitory neurotransmitter in the central nervous system, responsible for reducing neural excitability and calming nervous tension.

Endorphins

Endogenous opiate-like peptide neurotransmitters that elevate mood, induce euphoria, and alleviate physical pain in situations of strenuous exercise or injury.

Norepinephrine

A neurotransmitter and stress hormone that increases alertness, physical vigilance, and sympathetic arousal during high-stress situations.

Substance P

A neuropeptide neurotransmitter involved in transmitting noxious pain signals into the central nervous system and mediating inflammatory processes.

Agonist

A chemical agent or psychoactive substance that binds to a neurotransmitter's receptor site, mimicking or amplifying its biological response.

Antagonist

A chemical agent or psychoactive substance that occupies receptor sites on a receiving neuron, blocking endogenous neurotransmitters from triggering an action potential.

Tolerance

The neuroadaptive state where repeated exposure to a psychoactive substance diminishes its efficacy, necessitating progressively higher doses to achieve original levels of effect.

Withdrawal

The cluster of uncomfortable, distressful physical and psychological symptoms that emerge when a physically dependent individual ceases intake of an addictive substance.

Electroencephalogram (EEG)

A non-invasive diagnostic technique that records the rhythmic electrical voltage fluctuations generated by cortical neurons via electrodes arrayed across the scalp.

Functional Magnetic Resonance Imaging (fMRI)

A neuroimaging modality that measures changes in blood flow and oxygenation to visualize both brain anatomy and real-time localized neural activation.

Brainstem

The central core structure of the hindbrain connecting the spinal cord to higher brain centers, responsible for governing automatic, vital autonomic survival functions.

Medulla Oblongata

The lowermost segment of the brainstem that directly controls basic autonomic reflexes and involuntary life-sustaining functions, including cardiac rhythm, blood pressure, and breathing.

Reticular Activating System (RAS)

A nerve network extending through the core of the brainstem into the midbrain and thalamus, playing an essential role in modulating physiological arousal, alertness, and consciousness.

Thalamus

The central sensory relay hub located atop the brainstem that filters, processes, and directs incoming sensory messages (with the exception of olfaction) to corresponding areas of the cerebral cortex.

Cerebellum

The hindbrain structure situated beneath the occipital lobes that coordinates voluntary muscular motor activity, balance, postural equilibrium, and implicit procedural memories.

Limbic System

A circuit of subcortical brain structures (including the hippocampus, amygdala, and hypothalamus) positioned below the cerebral cortex, mediating emotion, motivation, and memory consolidation.

Amygdala

A pair of almond-shaped neural clusters in the limbic system that are primarily involved in processing emotional responses, particularly acute fear, rage, and aggressive behavior.

Hippocampus

A limbic system structure integral to encoding, consolidating, and processing explicit (declarative) memories for long-term storage.

Hypothalamus

A subcortical limbic structure situated beneath the thalamus that regulates internal homeostatic systems (eating, drinking, body temperature) and governs the endocrine system via control of the pituitary gland.

Pituitary Gland

The primary 'master gland' of the endocrine system, positioned just below the hypothalamus, which synthesizes regulatory hormones that guide growth and direct the secretion of other endocrine glands.

Cerebral Cortex

The thin outer mantle of interconnected gray matter covering the cerebral hemispheres, responsible for sophisticated cognitive processing, sensory perception, motor control, and language.

Corpus Callosum

The broad, dense band of transverse axon fibers that bridges the left and right cerebral hemispheres, mediating communication between them.

Frontal Lobe

The cortical lobe located directly behind the forehead, responsible for executive cognitive functions, motor control, expressive language, reasoning, and long-term planning.

Parietal Lobe

The region of the cerebral cortex situated between the frontal and occipital lobes that integrates tactile sensations, temperature, pain, and spatial orientation.

Occipital Lobe

The cortical lobe positioned at the rear base of the skull, housing the primary visual cortex dedicated to receiving and processing visual stimuli.

Temporal Lobe

The lateral cortical lobes located near the ears, containing structures critical for auditory perception, language comprehension, and memory retention.

Prefrontal Cortex

The anterior-most cortical region of the frontal lobe that underpins high-order executive functioning, abstract judgment, prospective planning, problem-solving, and emotional self-regulation.

Motor Cortex

A strip of cerebral tissue situated along the posterior border of the frontal lobe that plans, directs, and initiates voluntary muscular movements throughout the body.

Somatosensory Cortex

A band of cortical tissue situated at the anterior border of the parietal lobe that processes incoming somatosensory signals such as touch, vibration, and temperature from bodily tissues.

Broca's Area

A specialized region within the left frontal lobe that controls the motor execution and patterns required for fluent speech production.

Broca's Aphasia

A non-fluent, expressive language impairment caused by damage to Broca's area, characterized by hesitant, laborious speech production despite relatively preserved verbal comprehension.

Wernicke's Area

A cortical language hub situated in the left temporal lobe, dedicated to interpreting and comprehending spoken and written communication.

Wernicke's Aphasia

A receptive language disorder triggered by structural lesions to Wernicke's area, resulting in fluent, syntactically intact, but nonsensical speech coupled with severe deficits in language comprehension.

Lateralization

The asymmetric specialization of distinct cognitive, linguistic, and motor operations across the left and right cerebral hemispheres.

Contralateral Control

The cross-wired organization of the nervous system wherein each cerebral hemisphere receives sensory inputs from and executes motor actions on the opposing side of the body.

Association Areas

Expansive cortical territories outside the primary sensory and motor regions that integrate distributed sensory and memory representations to sustain abstract reasoning, planning, and judgment.

Neuroplasticity

The capacity of the nervous system to dynamically reorganize its neural architecture, form novel synaptic associations, and reassign cognitive or motor functions in response to experience or brain injury.

Split-Brain Condition

A surgical or developmental state where the corpus callosum is transected, preventing interhemispheric communication and isolating independent perceptual and cognitive operations between the left and right hemispheres.