Spinal Cord/Nerves Flashcards
What are the 2 functions of the spinal nerves that are attached to the spinal cord?
- a pathway for sensory and motor impulses
- responsible for reflexes, which are our quickest reactions to a stimulus
Describe the shape of the spinal cord.
roughly cylindrical, slightly flattened posteriorly and anteriorly
What are the names of the 2 longitudinal depressions on the external surface of the spinal cord?
- posterior median sulcus
- anterior median fissure
What are the 5 parts of the spinal cord?
- cervical
- thoracic
- lumbar
- sacral
- coccygeal
The spinal cord is (longer/shorter) than the vertebral canal that houses it.
shorter
The tapering inferior end of the spinal cord is called the _____ ______.
conus medullaris
Describe the conus medullaris.
- official “end” of the spinal cord proper
- usually at the level of the first lumbar vertebra
What is the cauda equina?
groups of axons inferior to the conus medullaris that project from the spinal cord
What is the filum terminale?
thin strand of pia matter within the cauda equina that helps anchor the conus medullaris to the coccyx
The spinal cord is associated with how many pairs of spinal nerves? How are these divided?
- 31 pairs
- 8 cervical nerves (C1-C8)
- 12 thoracic nerves (T1-T12)
- 5 lumbar nerves (L1-L5)
- 5 sacral nerves (S1-S5)
- 1 coccygeal nerve (Co1)
What are spinal cord meninges?
- protects and encapsulates the spinal cord
- continuous with the cranial meninges
Where is the epidural space located and what is its functions?
- lies between dura mater and periosteum covering the inner walls of the vertebra
- houses areolar connective tissue, blood vessels, and adipose connective tissue
Where is the dura mater located and what is its functions?
- most external of the meninges
- fuses with the connective layers that surround the spinal nerves
What two things does the subdural space separate?
separates the dura mater from the arachnoid mater
Where is the arachnoid mater located?
deep to the dura mater and the subdural space
________ space is filled with CSF.
subarachnoid
Where is the pia mater located and what is its functions?
- innermost meninx that adheres directly to the spinal cord
- delicate layer composed of elastic and collagen fibres and supports some of the blood vessels supplying the spinal cord
The spinal cord is partitioned into an inner ____ matter region and an outer ____ matter region.
- gray
- white
What does gray matter consist of?
- dendrites and cell bodies of neurons
- unmyelinated axons
- glial cells
What does white matter consist of?
myelinated axons
Briefly describe the distribution of gray matter.
- centrally located in spinal cord
- sectioned shape resembles a butterfly
Name and describe the 4 subdivisions of gray matter.
- anterior horns: cell bodies, motor neurone
- lateral horns: cell bodies, autonomic motor neurons (T1-L2)
- posterior horns: axons of sensory neurons, cell bodies of interneurons
- gray commissure: unmyelinated axons, connection between left and right side
Within the gray matter are functional groups of neuron cell bodies called _____.
nuclei
What are the 3 types of nuclei within gray matter?
- sensory nuclei: posterior horns
- motor nuclei: anterior horns
- autonomic motor nuclei: lateral horns
What kind of axons are spinal nerves made up of?
- motor
- sensory
Name the connective tissue wrappings of spinal nerves.
- endoneurium
- perineurium
- epineurium
Each anterior root and its corresponding posterior root unite within the ________ ________ to become a spinal nerve.
intervertebral foramen
How are spinal nerves numbered?
according to the location of the intervertebral canal
Where do the spinal nerves exit?
- In the cervical region, the first 7 pairs of spinal nerves (C1-C7) exit the intervertebral foramen above the vertebra of the same number
- eighth pair of cervical spinal nerves (C8) exit above the first thoracic vertebra
- the remaining pairs of spinal nerves exit below the vertebra of the same number
