Spinal cord & Brain regions Flashcards
What are the anatomical boundaries and supporting structures of the spinal cord?
Extends from foramen magnum to L1/L2 vertebral levels
Terminates as conus medullaris
Anchored by: Filum terminale (pia mater extension from conus to coccyx)
- Denticulate ligaments (21 pairs of pia mater extensions anchoring cord to dura)
Describe in detail the gray matter organization in spinal cord cross-sections
Butterfly-shaped gray matter with: Dorsal (posterior) horns: Receive somatic/visceral sensory input via interneurons
Ventral (anterior) horns: Contain cell bodies of somatic motor neurons
Lateral horns: Present only from T1-L2, contain sympathetic preganglionic neurons
Gray commissure: Connects bilateral gray matter, contains central canal with CS
Explain the formation and components of spinal nerves
Dorsal roots: Contain afferent fibers from sensory receptors. Have dorsal root ganglia
Ventral roots: Contain efferent fibers from motor neurons
Include somatic motor and autonomic (T1-L2) fibers
Describe the organization and function of spinal white matter columns
Dorsal (posterior): Mainly ascending sensory tracts (e.g., fasciculus gracilis/cuneatus)
Lateral: Both ascending (spinothalamic) and descending (corticospinal) tracts
Ventral (anterior): Primarily descending motor tracts and anterior spinothalamic tract
Spinal cord (white matter) Run in three directions:
- Ascending – up to higher centers (sensory inputs)
- Descending – from brain to cord or lower cord levels (motor outputs)
- Transverse – from one side to other (commissural fibers)
What is the “executive suite” of the brain, and what are its functions?
The cerebral cortex. It enables consciousness, sensory perception, voluntary motor initiation, communication, memory storage, and understanding.
Where is the primary motor cortex located, and what does it do?
In the precentral gyrus of the frontal lobe; controls conscious, skilled skeletal muscle movements via pyramidal cells.
pyramidal cells allow control of skeletal muscles; long axons project to spinal
cord as pyramidal/corticospinal tracts
What are pyramidal tracts?
Long axons from pyramidal cells that form corticospinal tracts projecting down the spinal cord.
What is somatotopy?
Mapping of body muscles to specific areas on the primary motor cortex
What is the motor homunculus?
A visual map of the contralateral motor innervation of the body.
What does the premotor cortex do and location.
Location: Anterior to precentral gyrus, frontal lobe
Function: Plans and sequences complex movements; coordinates multiple muscle groups
muscle memory
Broca’s Area
Location: anterior to inferior premotor area : Frontal lobe (usually left hemisphere), overlaps Brodmann areas 44 & 45
Function: Motor speech control; planning speech and some voluntary motor functions
Frontal Eye Field
Location: Frontal lobe, Brodmann area 8
Function: Controls voluntary eye movements
Primary Somatosensory Cortex
Location: Postcentral gyrus, parietal lobe
Function: Receives sensory input from skin, ad proprioceptors for muscles, joints; spatial discrimination
Somatosensory Association Cortex
Location: Posterior to primary somatosensory cortex
Function: Integrates sensory input to understand object shape, size, texture
Primary Visual Cortex
Location: Extreme posterior tip of occipital lobe
Function: Receives visual input from retinas
Visual Association Area
Location: Surrounds primary visual cortex
Function: Interprets visual stimuli using memory (e.g., recognizing faces
Primary Auditory Cortex
Location: Superior margin of temporal lobe
Function: Interprets sound (pitch, loudness, location)
Auditory Association Area
Location: Posterior to primary auditory cortex
Function: Stores and interprets sound memories
Vestibular Cortex
Location: Posterior part of insula and adjacent parietal cortex
Function: Conscious awareness of balance and head position
Gustatory Cortex
Location: Insula, deep to temporal lobe
Function: Perception of taste
Olfactory Cortex
Location: Medial temporal lobes (piriform lobes)
Function: Conscious awareness of smells
Anterior Association Area (Prefrontal Cortex)
Location: Frontal lobe
Function: Intellect, reasoning, personality, planning, memory; mood (linked to limbic system)
Posterior Association Area
Location: Parts of temporal, parietal, and occipital lobes
Function: Integrates sensory input, recognizes faces/patterns, involved in language understanding (Wernicke’s area)
Limbic Association Area
Location: Cingulate gyrus, parahippocampal gyrus, hippocampus
Function: Emotional responses; memory formation; gives emotional significance to events
