CH 3 A: Biology and Behavior – Nervous System & Brain

Vocabulary flashcards covering key structures, functions, and mechanisms of the nervous system and brain as outlined in the lecture notes.

Central Nervous System (CNS)

Comprised of the brain, spinal cord, and retina; the core of information processing.

Peripheral Nervous System (PNS)

All nerve cells outside the CNS; includes somatic and autonomic divisions.

Somatic Nervous System

PNS branch that conveys sensory information to the CNS and motor commands to muscles.

Autonomic Nervous System

PNS branch regulating involuntary bodily functions; subdivided into sympathetic and parasympathetic systems.

Sympathetic Nervous System

Autonomic division that prepares the body for fight-or-flight reactions.

Parasympathetic Nervous System

Autonomic division that conserves energy and restores the body to resting state.

Neuron

Basic unit of the nervous system that receives, integrates, and transmits information using electrical and chemical signals.

Dendrite

Branch-like neuron extension that detects and receives information from other neurons.

Cell Body (Soma)

Neuron region where incoming information is collected and integrated.

Axon

Long projection that carries neural impulses away from the soma toward other cells.

Myelin Sheath

Fatty insulating layer around many axons that speeds electrical conduction.

Node of Ranvier

Gap between myelin segments where action potentials are regenerated.

Terminal Buttons

Small knobs at an axon’s end that release neurotransmitters into the synapse.

Synapse

Junction between a sending axon and a receiving dendrite where chemical communication occurs.

Sensory Neuron

Neuron that detects information from the physical world and relays it to the brain.

Motor Neuron

Neuron that directs muscles to contract or relax, producing movement.

Resting Membrane Potential

Electrical charge (≈ –70 mV) of a neuron when inactive; inside is more negative than outside.

Polarization

State of a neuron with more negative ions inside than outside, creating electrical potential energy.

Action Potential

All-or-none electrical impulse that travels down the axon and triggers neurotransmitter release.

Depolarization

Phase in which membrane potential becomes less negative as Na⁺ ions rush in.

Repolarization

Return of the membrane potential toward the resting level after an action potential.

Refractory Period

Brief time after an action potential when a neuron cannot fire again.

Na⁺/K⁺ Pump

Active transporter that moves 3 Na⁺ out and 2 K⁺ into a neuron, restoring resting potential.

Myelin

Glial-derived insulation that increases action-potential speed along axons.

Neurotransmitter

Chemical messenger released at synapses to stimulate or inhibit neighboring cells.

Synaptic Transmission

Process of chemical communication across a synapse using neurotransmitters.

Reuptake

Reabsorption of released neurotransmitter back into the presynaptic neuron.

Glutamate

Primary excitatory neurotransmitter in the nervous system; increases cell firing.

GABA

Primary inhibitory neurotransmitter in the nervous system; decreases cell firing.

Selective Serotonin Reuptake Inhibitor (SSRI)

Drug class that blocks serotonin reuptake, enhancing synaptic serotonin signaling.

Meninges

Protective three-layer membrane covering the brain and spinal cord.

Cerebrospinal Fluid (CSF)

Fluid that cushions the brain and spinal cord, providing additional protection.

Brainstem

Extension of the spinal cord housing survival functions like breathing and heart rate.

Medulla Oblongata

Brainstem structure controlling heart rate and blood pressure.

Pons

Brainstem structure involved in sleep and arousal regulation.

Midbrain

Brainstem region containing sensory relay nuclei such as the thalamus and hypothalamus.

Reticular Formation

Brainstem network important for sleep and arousal.

Thalamus

“Gateway to the cortex”; relays sensory information to the cerebral cortex.

Basal Ganglia

Group of subcortical structures governing voluntary movement and reward; degenerates in Parkinson’s disease.

Cerebellum

Structure essential for balance, motor coordination, and motor learning.

Limbic System

Interconnected structures that initiate, control, and regulate emotions.

Hypothalamus

Limbic structure regulating motivation, homeostasis, and the four F’s (fight, flight, feeding, sex).

Hippocampus

Limbic structure critical for forming long-term memories.

Anterior Cingulate Cortex (ACC)

Cingulate region involved in decision-making, emotion, reward anticipation, and empathy.

Posterior Cingulate Cortex (PCC)

Cingulate region implicated in memory and visual processing.

Amygdala

Limbic nucleus important for fear, aggression, and emotional processing.

Nucleus Accumbens (NAc)

Key reward-circuit structure activated during pleasurable experiences and drug use.

Ventral Tegmental Area (VTA)

Midbrain source of dopamine neurons projecting to reward circuitry.

Corpus Callosum

Massive bundle of axons connecting the left and right cerebral hemispheres.

Split Brain

Condition in which the corpus callosum is severed, isolating the two hemispheres.

Cerebral Cortex (Neocortex)

Folded outer brain layer responsible for complex thought, perception, and behavior.

Frontal Lobe

Cortical lobe for planning, movement, and higher cognition; houses primary motor cortex.

Parietal Lobe

Cortical lobe processing touch and spatial relations; contains primary somatosensory cortex.

Temporal Lobe

Cortical lobe for hearing and memory; includes primary auditory cortex and face recognition areas.

Occipital Lobe

Cortical lobe housing primary visual cortex for vision processing.

Prefrontal Cortex (PFc)

Anterior frontal region involved in planning, attention, and judgment.

Orbitofrontal Cortex

PFc area linked to smell and emotion regulation.

Primary Motor Cortex

Frontal-lobe strip controlling voluntary muscle movements.

Primary Somatosensory Cortex

Parietal-lobe strip that localizes touch, pain, and body position.

Primary Visual Cortex

Occipital-lobe area receiving visual input from the eyes.

Primary Auditory Cortex

Temporal-lobe area processing sound information.

Gustatory Cortex

Region in parietal lobe dedicated to taste perception.

Olfactory Cortex

Temporal-lobe region responsible for smell processing.

Electroencephalograph (EEG)

Technique measuring brain’s electrical activity; high temporal, poor spatial resolution.

Positron Emission Tomography (PET)

Imaging method using radioactive tracers to assess metabolic brain activity; good spatial resolution.

Magnetic Resonance Imaging (MRI)

Technique using strong magnets to produce high-quality static images of brain anatomy.

Functional MRI (fMRI)

Imaging method tracking blood-oxygen changes to map brain activity; good spatial, poor temporal resolution.

Transcranial Magnetic Stimulation (TMS)

Non-invasive technique that briefly disrupts neural activity with strong magnetic pulses to study brain function.