Chapter 9 - Nervous System Vocabulary

Comprehensive vocabulary flashcards covering Chapter 9 - Nervous System, including CNS/PNS divisions, neuron structures, glial cells, impulses, neurotransmitters, brain structures, spinal cord pathways, reflexes, meninges, CSF, cranial nerves, and ANS divisions.

Central Nervous System (CNS)

The brain and spinal cord; acts as the control center that processes information and makes decisions.

Peripheral Nervous System (PNS)

Nerves outside the brain and spinal cord; acts as wiring that carries messages to and from the CNS.

Sensory Pathways

Nerve pathways that carry information toward the CNS.

Motor Pathways

Nerve pathways that carry commands away from the CNS.

Somatic Nervous System

Subdivision of the PNS that controls voluntary skeletal muscle movement.

Autonomic Nervous System (ANS)

Subdivision of the PNS that controls involuntary functions, targeting cardiac muscle, smooth muscle, and glands.

Neuron Structure

The basic functional cell of the nervous system, where nerve impulses travel in sequence: dendrites → cell body → axon → terminals.

Dendrites

Neuronal structures that receive incoming signals.

Cell Body

Part of the neuron containing the nucleus that keeps the neuron alive.

Axon

Neuronal structure that carries the nerve impulse away from the cell body.

Myelin

Fatty insulation around many axons that insulates the axon and makes impulses travel faster.

Axon Terminals

Structures at the end of an axon that release neurotransmitters at synapses.

Sensory (Afferent) Neuron

Neuron type that carries information from sensory receptors to the CNS (Afferent = Arrives at CNS).

Interneuron

Neuron type that connects neurons within the CNS.

Motor (Efferent) Neuron

Neuron type that carries commands from the CNS to muscles and glands (Efferent = Exits CNS).

Glial Cells

Cells that support, protect, nourish, and insulate neurons.

Astrocytes

Glial cells that support neurons and help maintain the nervous-system environment.

Microglia

Immune-defense glial cells that remove damaged material.

Oligodendrocytes

Glial cells that form myelin in the Central Nervous System (CNS).

Schwann Cells

Glial cells that form myelin in the Peripheral Nervous System (PNS).

Action Potential

The electrical signal traveling along an axon.

Depolarization

The process where the cell membrane becomes less negative as a nerve impulse begins.

Repolarization

The process where the cell membrane returns toward its resting state.

Saltatory Conduction

Conduction pattern that occurs when the nerve impulse jumps from node to node along a myelinated axon.

Synapse

The communication point between neurons or between a neuron and an effector.

Neurotransmitters

Chemicals released by neurons at synapses that affect the next cell.

Acetylcholine (ACh)

Neurotransmitter with excitatory or inhibitory effects; involved in memory and parasympathetic effects.

Norepinephrine (NE)

Neurotransmitter with excitatory or inhibitory effects; important in sympathetic effects and emotional responses.

Dopamine

Neurotransmitter that is mostly inhibitory; involved in motor control, emotions, and moods.

Serotonin

Neurotransmitter that is mostly inhibitory; involved in sleep, emotions, and moods.

Endorphins / Enkephalins

Neurotransmitters that help block pain.

Nitric Oxide (NO)

Gaseous neurotransmitter that can diffuse directly across cell membranes.

Main Brain Divisions

The four main anatomical divisions of the brain: cerebrum, diencephalon, brainstem, and cerebellum.

Cerebrum

Largest brain division responsible for thinking, memory, sensation, voluntary movement, consciousness, and emotions.

Diencephalon

Brain division consisting of the thalamus and hypothalamus.

Brainstem

Brain division consisting of the medulla oblongata, pons, and midbrain.

Cerebellum

Brain region that coordinates movement, balance, posture, and smooth movements.

Medulla Oblongata

Part of the brainstem that controls heart rate, breathing, blood vessel control, and contains important reflex centers.

Pons

Part of the brainstem responsible for two-way conduction and helping influence respiration.

Midbrain

Part of the brainstem that relays visual and auditory impulses.

Hypothalamus

Diencephalon structure regulating temperature, water balance, appetite, sleep, emotions, and endocrine control.

Thalamus

Major sensory relay station to the cerebral cortex involved in alertness.

Pineal Gland

Gland that produces melatonin and helps regulate the body's internal clock.

Gyri

Raised ridges of the cerebral cortex.

Sulci

Grooves located between gyri of the cerebral cortex.

Fissures

Deep grooves located within the brain structure.

Corpus Callosum

Large band of nerve fibers connecting the right and left cerebral hemispheres.

Cerebral Cortex

Outer gray-matter layer of the cerebrum.

Basal Nuclei (Basal Ganglia)

Subcortical structures that help produce automatic movements and posture.

Frontal Lobe

Cerebral lobe involved in voluntary movement, planning, judgment, personality, and Broca speech production area.

Parietal Lobe

Cerebral lobe responsible for body sensations and sensory processing.

Temporal Lobe

Cerebral lobe responsible for hearing and auditory processing.

Occipital Lobe

Cerebral lobe responsible for vision processing.

Wernicke Area

Brain area responsible for understanding sensory speech and language.

Primary Motor Area

Cortical area that controls voluntary skeletal muscle movement.

Primary Somatic Sensory Area

Cortical area responsible for body-sense perception.

Spinal Cord Anatomy

Major communication pathway between brain and body containing central gray matter surrounded by white matter.

Gray Matter

Central H-shaped region of the spinal cord containing neuron cell bodies and synapses.

White Matter

Region surrounding gray matter in the spinal cord that contains myelinated nerve fibers.

Ascending Tracts

Nerve tracts in the spinal cord that carry sensory impulses up to the brain.

Descending Tracts

Nerve tracts in the spinal cord that carry motor impulses down from the brain.

Spinal Roots and Pathways

Diagram showing dorsal roots carrying sensory input in and ventral roots carrying motor output out.

Dorsal Root

Spinal nerve root responsible for carrying sensory input into the spinal cord.

Ventral Root

Spinal nerve root responsible for carrying motor output out of the spinal cord.

Dorsal Root Ganglion

Swelling on the dorsal root containing sensory neuron cell bodies.

Reflex

A rapid, automatic response to a stimulus.

Reflex Arc Pathway

The pathway of a reflex response: receptor → sensory neuron → CNS/interneuron → motor neuron → effector.

Withdrawal Reflex

A reflex that pulls a body part away from something harmful.

Knee-jerk Reflex

A common example of a jerk or stretch reflex.

Dura Mater

Tough outer layer of the meninges.

Arachnoid Mater

Spiderweb-like middle layer of the meninges.

Pia Mater

Thin inner layer of the meninges directly covering the brain and spinal cord.

Subarachnoid Space

Space located between the arachnoid and pia mater that contains cerebrospinal fluid.

Cerebrospinal Fluid (CSF)

Fluid found in ventricles and subarachnoid spaces that cushions and supports the brain and spinal cord.

Choroid Plexus

Vascular structure in the ventricles that produces cerebrospinal fluid (CSF).

Lumbar Puncture

Procedure used to obtain CSF from the lower spinal canal.

Plexus

Network where nerves from different spinal levels combine and reorganize.

Dermatome

Skin area supplied mainly by one single spinal nerve.

Olfactory Nerve (CN I)

Cranial nerve I; responsible for smell.

Optic Nerve (CN II)

Cranial nerve II; responsible for vision.

Oculomotor Nerve (CN III)

Cranial nerve III; responsible for most eye movements and pupil/lens functions.

Trochlear Nerve (CN IV)

Cranial nerve IV; responsible for eye movement.

Trigeminal Nerve (CN V)

Cranial nerve V; responsible for face sensation and chewing.

Abducens Nerve (CN VI)

Cranial nerve VI; responsible for eye movement.

Facial Nerve (CN VII)

Cranial nerve VII; responsible for taste and facial expression.

Vestibulocochlear Nerve (CN VIII)

Cranial nerve VIII; responsible for hearing and balance.

Glossopharyngeal Nerve (CN IX)

Cranial nerve IX; responsible for taste/throat sensation, swallowing, and saliva production.

Vagus Nerve (CN X)

Cranial nerve X; responsible for throat/larynx, thoracic, and abdominal organ functions.

Accessory Nerve (CN XI)

Cranial nerve XI; responsible for shoulder and neck movement.

Hypoglossal Nerve (CN XII)

Cranial nerve XII; responsible for tongue movement.

Sympathetic Division

Division of the autonomic nervous system responsible for fight-or-flight responses.