Chapter 13 - The Spinal Cord and Spinal Nerves Flashcards
spinal meninges/meninx
connective tissue coverings that encircle the spinal cord and brain, continuous with the cranial meninges, surround spinal cord
epidural space
The spinal cord is also protected by a cushion of fat and connective tissue located in the epidural space. a space between the dura mater and the wall of the vertebral canal.
dura mater
Thick, strong layer composed of dense irregular connective tissue.
arachnoid mater
Middle, thin, avascular, loosely arranged collagen and elastic fibers. spider web.
subdural space
between dura mater and arachnoid mater, contains interstitial fluid
pia mater
Thin, transparent connective tissue layer, adheres to the surface of the spinal cord and brain. Squamous to cuboidal cells within interlacing bundles of collagen fibers and some fine elastic fibers. many blood vessels.
subarachnoid space
Between the arachnoid mater and pia mate, contains shock-absorbing cerebrospinal fluid.
cervical and lumbar enlargements
the cervical enlargement, extends from the fourth cervical vertebra (C4) to the first thoracic vertebra (T1). Nerves to and from the upper limbs arise from the cervical enlargement. The inferior enlarge- ment, called the lumbar enlargement, extends from the ninth to the twelfth thoracic vertebra. Nerves to and from the lower limbs arise from the lumbar enlargement.
conus medullaris
tapering, conical structure ends at the level of the intervertebral disc between the first and second lumbar vertebrae (L1–L2) in adults.
filum terminale
Arising from the conus medullaris an extension of the pia mater that extends inferiorly, fuses with the arachnoid mater and dura mater, anchors the spinal cord to the coccyx.
spinal nerves
paths of communication between the spinal cord and specific regions of the body. 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
cauda equina
the lumbar, sacral, and coccygeal regions of the spinal cord do not leave the vertebral column at the same level they exit the cord. The roots of these lower spinal nerves angle inferiorly alongside the filum terminale in the vertebral canal like wisps of hair.
anterior median fissue
wide groove on the anterior (ventral) side.
posterior median sulcus
a narrow furrow on the posterior (dorsal) side.
gray commissure
forms the crossbar of the H.
central canal
center of the gray commissure is a small space , extends the entire length of the spinal cord and is filled with cerebrospinal fluid. , continuous with the fourth ventricle
anterior or ventral white commissure
connects the white matter of the right and left sides of the spinal cord.
nuclei
clusters of neuronal cell bodies form functional groups
posterior (dorsal) gray horn
contain cell bodies and axons of interneurons as well as axons of incoming sensory neurons
anterior (ventral) gray horn
contain somatic motor nuclei, which are clusters of cell bodies of somatic motor neurons that provide nerve impulses for contraction of skeletal muscles.
lateral gray horn
Between the posterior and anterior gray horns
columns
The anterior and posterior gray horns divide the white matter on each side into three broad areas called columns: (1) anterior (ventral) white columns, (2) posterior (dorsal) white columns, and (3) lateral white columns
tract
bundles of axons having a common origin or destination and carrying similar information.
sensory (ascending) tract
consist of axons that conduct nerve impulses toward the brain.
motor (descending) tract
axons that carry nerve impulses from the brain