PT 7311 – Neuroanatomy Fundamentals

Vocabulary flashcards covering key neuroanatomical structures, pathways, and reflex concepts from the PT 7311 lecture notes.

Somatic (voluntary) motor system

Portion of the motor system that commands skeletal muscles under conscious control.

Visceral (autonomic) motor system

Motor division that regulates smooth muscle, cardiac muscle, and glands without conscious control.

Somatosensory

Sensory modality conveying pain, temperature, touch, and proprioception from the body.

Visceral sensory

Sensory input originating from internal organs (viscera).

Special sensory

Sensory modalities of hearing, taste, vestibular balance, vision, and smell.

Central Nervous System (CNS)

Composed of the brain and spinal cord; contains sensory, integrative, and motor neurons plus glial cells.

Peripheral Nervous System (PNS)

All neural structures outside the CNS; includes nerves, ganglia, sensory receptors, and glia.

Cerebral cortex

1⁄8-inch layer of neuronal cell bodies covering the cerebrum responsible for high-level functions like decision making and language.

Gyrus

Raised ridge on the cerebral surface that increases cortical surface area.

Sulcus

Groove between gyri on the cerebral surface.

Fissure

Deep groove on the brain surface; e.g., the longitudinal cerebral fissure separating hemispheres.

Frontal lobe

Cerebral lobe for executive functions and voluntary motor control of body, head, eyes, and speech.

Pre-central gyrus (primary motor cortex)

Frontal-lobe ridge anterior to central sulcus containing upper motor neurons that initiate contralateral voluntary movement.

Parietal lobe

Lobe involved in sensory processing, integration, and visual–spatial functions.

Post-central gyrus (primary somatosensory cortex)

Parietal-lobe ridge posterior to central sulcus receiving contralateral body somatosensory input from thalamus.

Occipital lobe

Posterior cerebral lobe housing the primary visual cortex.

Temporal lobe

Lobe containing language systems, memory centers, and visual processing areas.

Limbic lobe

Cortical region governing survival drives, emotions, and memory.

Basal nuclei (basal ganglia)

Subcortical gray matter group that selects movements and stores learned motor patterns.

Hippocampus

Limbic structure essential for memory formation.

Amygdala

Limbic structure mediating emotion, especially fear and aggression.

Thalamus

Bilateral relay station that filters and distributes all sensory information (except smell) to the cortex.

Midbrain

Superior brainstem division located caudal to the thalamus.

Pons

Middle brainstem division situated caudal to the midbrain and rostral to the medulla.

Medulla

Inferior brainstem segment continuous with the spinal cord; houses autonomic centers.

Brainstem

Collective term for the midbrain, pons, and medulla; lies anterior to the cerebellum and contains cranial nerve nuclei III–XII.

Cerebellum

‘Little brain’ posterior to the brainstem that modulates limb movements and supports motor learning.

Vermis

Midline cerebellar region that modulates trunk movements.

Neuron soma (cell body)

Metabolic center that synthesizes macromolecules and integrates electrical/chemical signals.

Dendrite

Neuron process that receives and collects synaptic information; can number from none to thousands.

Axon

Cylindrical neuron process that conducts action potentials away from the soma toward targets.

Upper Motor Neuron (UMN)

Motor neuron with its soma in the pre-central gyrus; its axon descends to influence lower motor neurons.

Lower Motor Neuron (LMN)

Neuronal cell body in the ventral horn whose axon exits the CNS to innervate skeletal muscle.

Pseudo-unipolar neuron

Sensory neuron with one process dividing into peripheral and central branches; found in dorsal root ganglia.

Gray matter

CNS regions composed mainly of neuronal cell bodies responsible for processing information.

White matter

CNS regions consisting of myelinated axons that carry information between areas.

Nucleus (neuroanatomy)

Cluster of neuronal cell bodies located within the CNS.

Ganglion

Cluster of neuronal cell bodies located in the PNS.

Tract

Bundle of axons connecting two distinct CNS regions, e.g., corticospinal tract.

Fasciculus

Bundle of axons traveling together within the CNS, e.g., fasciculus cuneatus.

Funiculus

Large white-matter column in the spinal cord comprising multiple tracts and fasciculi.

Nerve

Bundle of myelinated axons located in the PNS.

Spinal cord

CNS structure within the vertebral canal extending from foramen magnum to conus medullaris; has 31 segments.

Conus medullaris

Tapered terminal end of the spinal cord located at vertebral level L2.

Cauda equina

Bundle of lumbosacral nerve roots descending below the conus medullaris.

Dorsal horn

Gray-matter region receiving sensory afferent input.

Ventral horn

Gray-matter region housing lower motor neuron cell bodies.

Dorsal root

Bundle of sensory axons entering the spinal cord from a dorsal root ganglion.

Ventral root

Bundle of LMN axons exiting the spinal cord to supply muscles.

Dorsal Root Ganglion (DRG)

PNS ganglion containing cell bodies of pseudo-unipolar sensory neurons.

Monosynaptic Stretch Reflex (MSR)

Spinal reflex involving one synapse between sensory afferent and LMN at a single spinal level.

Muscle spindle

Intramuscular sensory receptor detecting muscle length and rate of length change; initiates the MSR.

Corticospinal tract

Descending UMN pathway from cortex to spinal cord that controls voluntary movement.

Spinothalamic tract

Ascending sensory pathway transmitting pain, temperature, and light touch to the thalamus.

Dorsal columns

Ascending pathway conveying discriminative touch, vibration, and conscious proprioception to the medulla.

Hyperreflexia

Exaggerated reflex response indicating intact reflex arc but loss of UMN inhibitory modulation.

Areflexia

Absence of reflex pointing to damage within the reflex arc itself, not necessarily UMN involvement.

Knee jerk (patellar tendon) reflex

Clinical test of the L2–L4 MSR; tendon tap stretches quadriceps, causing reflex contraction.

4-neuron somatosensory pathway

Sequence DRG → dorsal horn/medulla → thalamus → post-central gyrus conveying body sensation to cortex.

2-neuron motor pathway

UMN in cortex and LMN in ventral horn required to produce voluntary skeletal muscle contraction.