FINAL: sc and spinal nerves Flashcards
Where is the beginning/end of the s.c.? what is the end-pt called?
medulla to L2
end pt: conus medullaris
What are the 2 enlargement within the s.c.? describe each
Cervical enlargement:
- from which brachial plexus is formed
- innervated upper extremities (C5-T1)
Lumber enlargement:
- from which lumbar plexus is formed
- innervated lower extremities (L1-S4)
s.c. is divided into R/L halves by depressions called the:
- ant. (ventral) median fissure
- post. (dorsal) median sulcus
What is the H-form found when we transect the s.c.? what is it comprised of?
Grey commissures
- comprised of nuclei (grey matter)
What is the center of the grey matter of the grey commissures called? describe it.
Central canal
- continuous the length of the s.c.
- continuous w 4th ventricle
- filled w CSF
Surrounding H-form there are areas of: (describe)
white matter
- comprised of bundles of myelinated n. fibers (oligodendrocytes)
- each bundle is called a tract
Are spinal nerves within the vertebral canal?
no
What are ascending tracts? what do they relay and where?
sensory tracts
- relay impulses from periphery or spinal lvls to brain
What are descending tracts? what do they relay and where?
motor tracts
- relay impulses from brain to diff spinal lvls and periphery
The grey commissure has sets of horns:
- 2 ant. (ventral) horns
- 2 post. (dorsal) horns
- lateral horns: ONLY in T-spine and upper L-spine (T1-L2)
Dorsal roots contain which type of neurons (exiting from dorsal horn)? where are their cell bodies and what are they called?
sensory neurons (afferent)
- lie outside s.c. in the intervertebral foramen
- cell bodies: dorsal root ganglia or spinal ganglia
What do ventral roots contain (exit ventral horn)? where are the cell bodies?
axons of motor neurons (efferent)
- within ant. (ventral) and lateral horns
how many pairs of spinal nerves are there?
31
what kind of nerves are found in spinal nerves?
mixed: sensory and motor
What nervous system is associated with lateral horns?
ANS (efferent)
What NS is associated with anterior horns?
SNS (efferent)
What NS is associated with posterior horns?
SNS and ANS (afferent)
The spinal nerve divides into? (2 parts)
dorsal and ventral rami
What do dorsal rami supply?
deep vertebral muscles and skin of back
What do ventral rami supply?
ventral and lateral musculature
What is the role of meninges (what do they form the supporting framework for, what space do they enclose)?
- protect brain and s.c.
- framework for: arteries, veins, venous sinuses
- enclose subarachnoid space for circulation of CSF
Which meningeal layer covers the pituitary gland?
Dura Mater: diaphragm sellae
Where is the subarachnoid space?
Inf. to Arachnoid
What are denticulate ligaments?
extensions of Pia Mater along the s.c.
- go thru arachnoid to attach to dura
