week 9 Flashcards
the spinal cord is covered/protected by the …
vertebral bones, meninges, and cerebrospinal fluid, produced within the brain
the spinal cord is situated within the ______ ________
vertebral column
the spinal meninges are continuos with the …
cranial meninges
dura matter extends from …
foramen magnum to 2nd sacral vertebrae
the epidural space is filled with…
fat and connective tissue which are also protective to spinal cord
the middle meningeal layer is …
arachnoid matter, continuous with the arachnid of brain
what is the thin layer between dura and arachnoid, and it contains?
subdural space
interstitial fluid
the innermost meningeal layer is …, which adheres to the spinal cord surface.
It consists of ….
contains…
pia matter
consists of fine elastic and collagen fibers
contains blood vessels, supplying spinal cord with oxygen and nutrients
what is between arachnoid and pia matter?
it contains…
subarachnoid space
contains CSF
what are denticulate ligaments?
function?
pia matter forms triangular extensions called denticulate ligaments, which suspends the spinal cord in the middle of dural diameter
function is to protect against shock/sudden displacement
in adults, the spinal cord extends from
medulla oblongata to superior border of 2nd lumbar vertebrae
in newborns the spinal cord extends from…
3rd to 4th lumbar vertebra
*at the age of 4-5 yrs, growth of spinal cord stops, but the vertebral column continues to elongate.
eventually, the spinal cord ends at the horixontal level of L1 - L2 intervertebral disk
cervical enlargement extends from…
which nerves arise from them?
C4 - T1
nerves to and from upper limbs arise
lumbar enlargement extends from…
which nerves arise from them?
T9 - T12
nerves from lower limbs
inferior to lumbar enlargement, the spinal cord tapers into …,
which ends where in adults?
conus medullaris
ends at the level between L1 and L2
what arises from conus medullaris and what is its function?
filum terminale is an extension of pia matter that anchors the spinal cord to coccyx
what are cauda equina?
“horse’s tail”
nerves that exit/enter from the inferior part of the spinal cord leave the vertebral column not at the same vertebral level as spinal cord exit but angle inferiorly in the vertebral canal “like wisps of hair”.
the roots of these nerves are collectively called cauda equina
spinal cord is anatomically divided into …
how many are there?
transverse segments according to spinal nerves that are formed at each level
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal segment
31 total
the posterior/dorsal roots contain…
only afferent / sensory axons (somatic and visceral)
conducting nerve impulses from sensory receptors in the skin, muscles, and internal organs into the CNS
each posterior root has a “swelling” called…
posterior/dorsal root ganglion
which contains cell bodies of sensory neurons
anterior / ventral roots contains axons of …
efferent / motor neurons (somatic and visceral)
which conduct nerve impulses from CNS to effector organs and cells
the spinal nerves split into…
dorsal and ventral rami
the posterior rami supply…
innervate motor
the erector spinal muscles (efferent), joints (afferent), and overlying skin of trunk (afferent)
anterior rami supply…
innervate sensory
the muscles and the skin of the side and front of trunk, including the muscles and skin of the limbs (efferent and afferent)
they also supply sensory (afferent) fibers to the parietal pleural / parietal peritonenum
* the cervical, brachial and lumbosacral plexi (plexuses) derived from anterior rami, which from the roots of the plexi, therefore the term “root” has 2 different applications
the peripheral nerves comprise the…
cranial/spinal nerves linking the brain and spinal cord to the peripheral tissues
1) the first 7 cervical nerves emerges _____ corresponding vertebra
2) the C8 emerges between ____ and ____ vertebrae
3) the rest emerges _____ the corresponding vertebrae
1) ABOVE
2) C7 and T1
3) BELOW
1) the penetrating grooves divide the spinal cord into right / left sides, they are called?
2) which is less deep?
1) anterior median fissure and posterior median sulcus
2) posterior median sulcus
the gray commissure is the …
the center of the gray commissure is ….
crossbar of the “H”
central canal
where is white commissure and its function is?
situated anterior to gray commissure, and it connects the white matter of the right and left sides
the gray matter on each side of the spinal cord is subdivided into…
horns
anterior / ventral gray horns contain…
somatic and autonomic sensory nuclei
lateral gray horns are present only in…
contains…
present only in thoracic- lumbar- sacral segments)
contain the cell bodies of autonomic motor neurons (regulate activity of smooth muscle, cardiac muscle, and glands)
the white matter of the spinal cord is divided by the posterior and anterior gray horns into …
columns (funiculi)
each column contains
distinct bundles of axons - tracts (sensory/ascending, and motor/descending)
[within dorsal column]
1. fasciculus gracilis -
- fasciculus cuneatus -
- discriminative touch and conscious proprioception from the lower extremities
- same from upper extremities
[within lateral and ventral columns]
lateral and ventral corticospinal tracts
somatic motor
[within lateral and ventral columns]
anterior-lateral spinothalamic tracts
pain, temperature, and crude/light touch
[within lateral and ventral columns reticulospinal tracts (lateral, ventral)
subconscious motor neuron activity
[within lateral and ventral columns]
spinoreticular tracts
pass information to Reticular Activating System (RAS)
[within lateral columns only]
dorsal & ventral spinocerebellar tracts
subconscious proprioceptions/stereignosis
[within lateral columns only
hypothalamospinal tracts
controls ANS
[within ventral columns]
vestibulospinal tracts
somatic motor for equilibrium reflex
[within ventral columns]
medial longitudinal fasciculus
head movement to maintain equilibrium
each column contains distinct bundles of sxons - tracts (sensory/ascending, and motor/descending)
the major tracts within the spinal cord are…
- within dorsal column: fasciculus gracilis, fasciculus cuneatus
- within lateral and ventral columns: lateral and ventral corticospinal tracts; anterior-lateral spinothalamic tracts; reticulospinal tracts (lateral and ventral); spinoreticular tracts
- within lateral columns only: dorsal & ventral spinocerebellar tracts; hypothalamospinal tracts
- within ventral columns: vestibulospinal tracts; medial longitudial fasciculus
