8/20 Spinal cord Flashcards
what are the three layers of spinal meninges?
Dura mater; Arachnoid Mater; Pia mater
How are the meninges like a seatbelt?
they are between the spinal cord and the bone of the vertebral Column therefore they protect the spinal cord from the bard bone of the spine.
What is dura mater?
dense collagenous connective tissue that forms a cheath around the nurve
where is dura mater?
This is the outside laber of the meninges. found around the spinal cord - forms the epinarumas at each se. level as the nerve exists the intervertibral foraniumum
What is the arachnoid mater?
the mid-layer of the meninges, looks like spider webs to the spinal cord.
what is found in the suarachnoid space?
The crebral spinal fluid or CDF.
Where is CSF found and what is the function
in the Subarachnoid space, and it provides cushioning and immunologic protection.
what is Pia Mater?
loose connective tissue knitted to the spinal chord. The layer of the meninges that is closest to the spinal cord.
what is the function of the dentate ligaments
tether the spinal cord latterally to prevent it from jiggling back and forth. (looks like little ropes to the side of the spinal chord)
what is the function of the filum terminale?
Delicate strand of fibrous tissue of about 20 Cm, it proceeds form the Apex of the connus medullarua and gives longitudinal suppor to the spinal cord.
What is the relationship between dura mater and spinal cord
the spinal cord is within the dura matter which is whining the vetebral canal. this is a major part of the seat belt known as the meninges.
what is the conus medullaris
the bottom of the spinal cord in the Vet. Canal
what fills the space below the onus medullaris
the caadu equina and the CSF
Where in the vertebral column does the spinal cord end?
Around L1-L2
What is the name of the hole in the bottom of the skull?
the framun magnum
why is there a vertebrosegmental discrepancy between the spinal cord and vertebral column
the vertebral column develops faster than the spinal cord! The column elongates away from the spinal cord. The nerves still go down and under the associated vertibrate, they just aren’te next to each other anymore
What are the average dimendsions of the spinal cord?
lengh: 40-45 cm
weight: 35 Grams
Width: 1.75cm
why is it called gray matter?
it is gray because of the presence of cell bodies in this are of the spinal chord, and the absence of mylar sheeting. This is in the central part of the spinal chord the “butterfly”
identify the three horns of gray matter
Dorsal Horn (postier section); Ventral horn (anterior section); and lateral horn (intermediate)
what is the function of the Dorsal horn
Recieve sensory neuron input. Somatic input on the latteral part of the horn and the vissural sensory input in the more central part of the dorsal horn.
what is the function of the ventral horn
houses motor neurons: somatic towards the outside and vissural towards the center.
What is the function of the lateral horn
visceral motor neuron cell bodies innervates the visral glands and organs. t1 - l2 levels are the sympathetic and s2-s4: parasympathetic
Identify the cervical enlargement
where the horn gets bigger i the cervical region: due to the increased number of cell bodies in the gray matter.
identify the lumbar enlargment
the area in the lumbar where the dorsal/ventral horns get larger due to an increased number of neurons
what is the loolipop theory of vertibral horns
The size of the horn coorilates to the number of nuron cell boddies that are contained in the horn, which coorilates to the number of muscles/sensory nerves that are being innervated
What muscles are inervated by what regions of the vertebral colomn
cervical inervates the upper limb muscles, the thorasic innervates the abdominal and intercostal muscles (not so many). The lumbar inervates the lower limb muscles. and the sacral inervates the lower, lower limb muscles.
why dos the spinal cord swell in the cervical and lumbar vertebral regions?
Because they have more motor neuron cell bodies for upper and lower muscle control
Why is it called white matter?
the white matter consisted of myelinated tracts of nerves moving up and down the spinal cord. the oligodendrocytes the myelinate it make it look white
what is the funciton of the whit matter?
To contain tracts of axons moving up and down the spinal cord
What do the axons moving through the white matter transmit?
Transmit signals to and from the brain
Why does the white mattter get larger towards the cervical region
more tracts as you near the brain are entering the spinal chord on their way up or down from the brain
What information is in ascending tracts
sensory, pain infromation to the the brain
Dorsal column of the white matter
contains ascending ipsilateral sensory tracts for fine touch propriaception/ vibration [located between the dorsal horns of the gray matter]
What does ipsolateral mean?
that the nerves move up the same side of the spinal chord as they entered.
Anterolateral system of the white matter
ascending Info: contralateral sensory tracts for pain, temp. touch; they take info from the opposite side of the body. [located anterior of the ventral horns of the gray matter.
Corticospinal tract
located medial to the intermediate lobes of the gray matter: descending ipsolateral motor tract~ to the ventral horn gray matter and then out to the body.
what are distinguishing features of the Cervical cord segments?
Wide and flat segments, lots of whit matter and very big ventral horn enlargment since hand upper muscels and most of the neural tracts are located here.
what are distinguishing features of the Thoracic cord segments
latteral horn in the gray matter, and small ventral horns and pretty small dorsal horns too.
what are distinquinshing features of the Lumbar regions
large ventral horns and really round shape and less white matter.
what are distiquishing features fo the sacral cord sections
Large ventral horn, very little white matter and the smallest sections!
How many C,T,L and S vetebral segments are there?
C1-C7; T1-T12; L1-L5; S1-S5; 4 in cocigeal. 33 total
how many C,T,L and S spinal cord segments are there?
C1-C8; T1-T12; L1-L5; S1-S5 1 in coccigeal 31 in total
Explain the discrepancy between the cervical spine vertebra and cord numbering:
there are 7 vertibra and 8 cord sections, the occipital bone in the base of the skull is actually the first spinal bone and then the numbers would match. as it is the spinal cord segments leave the spine just above the coresponding vetebra number, until C-7/chord section C-8 where C7 cord section leaves just above C-7 vetebra and C-8 cord section leavses just below C-7 vetebra.
Describe the topographical change in the spinal cord as it descends
the sections get smaller and closer together.
describe the spinal chord in the thorasic section
The spinal chord sections exit below the corresponding vetebra, but as you descend the space between the two increases, the spinal chord section being superior to the vetebral section. {in the sacral section it is similar}
Identify the Suboccipital Triangle
Directly below and lateral of the suboccipital bone
What are the four muscles of the Suboccipital triangle
Rectus Capitaus posterior major; Rectus Capitis posterior minor muscle. Obliquus capitus superior muscle; Obliquus Capitus inferior muscle.
What is the important blood sorce through the suboccipital triangle
the Vertebral Artery
what are the two important nerves in the suboccipital region
uboccipital nerve; Greater occipital nerve
What seperates the Dorsal and Ventral roots as they exit the spinal cord
the Denticulate ligament
why is there a lumbar and cerivical enlargement?
Increased number of motor neuron and sensory neuron bodies to control more muscle regions
The ligament that runs superior to the cervical ligaments and connects to the suboccipital bone
nuchal ligament
The ligament that runs anterior of the vertebral colomn
Anterior Longitudinal ligaent
The ligament along the dorsal of the vertebral colomn
Suprasinous ligament
The ligament between the spinal processes
Interpinous ligament
The ligament below the vertebral arch
Ligamentum Flavum
The ligament just anterior the spinal cord
Posterior Longitudinal ligament.
What does nisel stain stain?
It stains rna in the er
