Neuroanatomy

Vocabulary flashcards covering key terms and structures from the neuroanatomy lecture, suitable for exam review.

Neuroanatomy

Study of the structure and organization of the nervous system.

Central Nervous System (CNS)

Brain and spinal cord; integrative and control centers.

Peripheral Nervous System (PNS)

All nerves outside the CNS; includes cranial and spinal nerves and sensory receptors.

Autonomic Nervous System (ANS)

Part of PNS that governs involuntary bodily functions.

Somatic Nervous System

Division of PNS controlling voluntary skeletal-muscle movement.

Sympathetic System

ANS subdivision mediating fight-or-flight responses (e.g., ↑ heart rate).

Parasympathetic System

ANS subdivision mediating rest-and-digest responses (e.g., ↓ heart rate).

Enteric System

ANS network that regulates gastrointestinal function.

Neuron

Functional nerve cell that transmits information via electrical and chemical signals.

Glial Cells

Supportive nervous-system cells that nourish, insulate, and protect neurons.

Astrocyte

Star-shaped glial cell providing nutrients, blood-brain barrier, and synapse support.

Oligodendrocyte

CNS glial cell that forms myelin sheaths around multiple axons.

Schwann Cell

PNS glial cell that myelinates a single axon segment.

Microglia

Phagocytic glial cells that remove debris and fight infection in CNS.

Soma (Cell Body)

Neuron’s metabolic center containing nucleus and organelles.

Dendrite

Branched neuron process receiving synaptic input.

Axon

Long neuron process that conducts impulses away from the soma.

Myelin Sheath

Fatty insulating layer around axons that speeds impulse conduction.

Nodes of Ranvier

Gaps between myelin segments where action potentials are regenerated.

Synaptic Cleft

Microscopic gap between communicating neurons at a synapse.

Neurotransmitter

Chemical messenger released to transmit signals across a synapse.

Excitation

Neural stimulation that increases target cell activity.

Inhibition

Neural stimulation that decreases target cell activity.

Monopolar Neuron

Neuron with one process that bifurcates into axon and dendrite.

Bipolar Neuron

Neuron with one axon and one dendrite (e.g., retina).

Multipolar Neuron

Neuron with one axon and multiple dendrites; most common type.

Mechanoreceptor

Sensor responding to mechanical deformation (touch, pressure, stretch).

Pacinian Corpuscle

Encapsulated receptor for deep pressure and high-frequency vibration.

Meissner's Corpuscle

Encapsulated receptor for fine touch and low-frequency vibration (fingertips, eyelids).

Ruffini Ending

Slow-adapting receptor responding to skin stretch.

Merkel Disc

Unencapsulated receptor for light touch in hairless skin.

Hair Follicle Receptor

Unencapsulated receptor sensing hair movement.

Muscle Spindle

Low-threshold receptor detecting muscle length and stretch.

Golgi Tendon Organ

Receptor monitoring tendon tension.

Labyrinth Hair Cell

Inner-ear mechanoreceptor for balance and hearing.

Chemoreceptor

Receptor detecting chemical stimuli (smell, taste).

Photoreceptor

Light-sensitive visual receptor in the retina.

Thermoreceptor

Receptor sensing temperature changes.

Telereceptor

Receptor activated by distant stimuli such as light or sound.

Interoceptor

Receptor monitoring internal body events (e.g., blood pressure).

Exteroceptor

Receptor responding to external stimuli (touch, vision, hearing).

Proprioception

Sense of body position and movement in space.

Basal Ganglia

Deep brain nuclei involved in background posture and smooth movement.

Cerebrum

Largest brain part; center of consciousness and voluntary movement.

Cerebellum

“Little brain” coordinating balance, posture, and fine motor control.

Cerebral Cortex

Outer gray matter of cerebrum responsible for higher brain functions.

Brainstem

Midbrain, pons, and medulla; controls basic life functions.

Midbrain

Superior brainstem region containing substantia nigra and reflex centers.

Pons

Middle brainstem region bridging cerebrum and cerebellum; houses CN V-VIII nuclei.

Medulla Oblongata

Inferior brainstem region controlling vital reflexes (heart rate, respiration).

Reticular Formation

Brainstem network regulating arousal and vital autonomic functions.

Meninges

Three protective membranes covering brain and spinal cord.

Dura Mater

Tough outer meningeal layer.

Arachnoid Mater

Web-like middle meningeal layer housing CSF.

Pia Mater

Delicate inner meningeal layer adhering to brain surface.

Subdural Hematoma

Blood pooling below dura mater, often from venous bleed.

Epidural Hematoma

Blood pooling between skull and dura mater, usually arterial.

Ventricles

CSF-filled cavities within the brain (lateral, third, fourth).

Cerebrospinal Fluid (CSF)

Clear fluid cushioning brain and spinal cord and removing waste.

Circle of Willis

Arterial ring uniting anterior and posterior cerebral blood flow.

Stroke

Rapid loss of brain function due to disrupted blood supply.

Thrombus

Stationary blood clot obstructing a vessel.

Embolism

Traveling clot or debris blocking blood flow.

Aneurysm

Balloon-like dilation of a weakened blood-vessel wall.

Thalamus

Paired relay station for almost all sensory information to cortex.

Hypothalamus

Almond-sized linker between nervous and endocrine systems; maintains homeostasis.

Subthalamus

Region beneath thalamus; lesions can cause involuntary flinging movements.

Corpus Callosum

Major commissural fiber bundle connecting left and right cerebral hemispheres.

Association Fibers

Axon bundles connecting regions within the same hemisphere.

Commissural Fibers

Axon bundles connecting the two hemispheres (e.g., corpus callosum).

Projection Fibers

Axons linking cortex with lower brain and spinal cord (e.g., internal capsule).

Broca's Area

Frontal-lobe speech-production center (Brodmann 44/45).

Wernicke's Area

Temporal-lobe language comprehension center (Brodmann 22).

Primary Motor Cortex

Precentral gyrus region initiating voluntary movement (Brodmann 4).

Homunculus

Body-map illustration of motor or sensory cortical representation.

Brodmann Areas

Numbered cortical regions defined by cytoarchitecture and related function.

Cranial Nerve I (Olfactory)

Sensory nerve for smell.

Cranial Nerve II (Optic)

Sensory nerve for vision.

Cranial Nerve V (Trigeminal)

Mixed nerve for facial sensation and mastication muscles.

Cranial Nerve X (Vagus)

Mixed nerve regulating larynx, pharynx, viscera, and parasympathetic output.

Corticospinal Tract

Descending motor pathway from cortex to spinal cord controlling limbs.

Corticobulbar Tract

Descending pathway from cortex to brainstem controlling cranial-nerve muscles.

Pyramidal System

Direct motor pathways (corticospinal & corticobulbar) for voluntary movement.

Extrapyramidal System

Indirect motor pathways controlling background tone and posture.

Automaticity

Performance of actions with minimal conscious control after practice.

Ataxia

Lack of voluntary coordination of muscle movements, often cerebellar.

Vermis

Midline cerebellar structure connecting its hemispheres.

Hemorrhagic Stroke

Brain damage due to bleeding within or around the brain.

Ischemic Stroke

Brain damage caused by lack of blood flow from clot or blockage.

Reflex Arc

Basic neural pathway producing an involuntary response to a stimulus.