Exam2 Flashcards
neuraxis
an imaginary line drawn through the center of the length of the CNS, from the bottom of the spinal cord to the front of the forebrain
ipsilateral
located on the same side of the body
contralateral
located on the opposite side of the body
transverse sections (cross sections)
with respect to the CNS, a slice taken at right angles to the neuraxis
frontal section (coronal section)
a slice through the brain parallel to the forehead
horizontal section
A slice through the brain parallel to the ground
sagittal sections
a slice through the brain parallel to the neuraxis and perpendicular to the ground
neural tube
a hollow tube, closed at the rostral end, that forms from ectodermal tissue early in embryonic development; serves as the origin of the CNS
ventricular zone
a layer of cells that line the inside of the neural tube; contains progenitor cells that divide and give rise to cells of the CNS
progenitor cells (founder cells)
cells of the ventricular zone that divide and give rise to cells of the CNS
radial glia
special glia with fibers that grow radially outward from the ventricular zone to the surface of the cortex; provide guidance for neurons migrating outward during brain development
symmetrical division
division of a progenitor cell that gives rise to two identical progenitor cells; increases the size of the ventricular zone and hence the brain that develops from it
asymmetrical division
division of a progenitor cell that gives rise to another progenitor cell and a neuron, which migrates away from the ventricular zone toward its final resting place in the brain
apoptosis
death of a cell caused by a chemical signal that activates a genetic mechanism inside the cell
cervical vertebrae
vertebrae of the neck area; 7 vertebrae
atlas
top cervical vertebra - pivot for head
Axis
2nd cervical vertebra; includes odontoid process
odontoid process
part of axis that forms pivot point
thoracic
upper chest cavity vertebrae; 12 vertebrae
articulations
point of attachment for ribs and hip bones
lumbar
lower back vertebrae ; five vertebrae
sacral
fused vertebrae forming back of pelvic girdle; five vertebrae
coccyx
fused vertebrae forming “tail bone”; five vertebrae
transverse process
bone extensions to each side of vertebrae, anchor points
spinous process
bone extensions on dorsal aspect of vertebrae, anchor points
central foramen
opening in the bone down the core of the vertebral column
dura mater
tough, outer protective layer of meninges
arachnoid
thin middle layer of meninges, lots of vascularization
pia mater
thin inner layer of meninges, holds shape and protects brain
central gray matter
neuron somas (butterfly)
dorsal root
afferent sensory fibers entering spinal cord
ventral root
efferent motor fibers leaving cord
dorsal root ganglion
unipolar somas of cutaneous sense neurons
Bell & Magendi
developed the “Law of Roots”
central lumen
circulation of CSF
fila
finger-like branching of the roots, distribute information through cord
Rami comunicantes
send info into the sympathetic ganglion chain
spinal root
a bundle of axons surrounded by connective tissue that occurs in pairs, which fuse and form a spinal nerve
cauda equine
horse’s tail; a bundle of spinal roots located caudal to the end of the spinal cord;
dorsal horn
contains somas for sending sensory info up to brain
ventral horn
contains somas for motor neurons
gracile tract
carries ipsilateral epicritic sensory info to brain stem
cuneate tract
carries ipsilateral epicritic sensory info to brain stem
ventral spinothalamic tract
carries contralateral protopathic info to brain
lateral spinothalamic tract
carries contralateral protopathic info to brain
direct pyramidal tract
carries ipsilateral motor info from cortex (20%)
lateral pyramidal tract
- carries contralateral motor info from cortex (80%)
simple reflex arc
a simple behavior performed by spinal neurons alone
segmental reflex
a reflex involving a single vertebral level
suprasegmental reflex
a reflex involving multiple vertebral levels
cranial vascularization
supplies the brain with blood
cerebral artery
serves the outer surface of brain
carotid artery
serves the inner core of brain
arachnoid granulations
enhances transfer between CSF and blood supply