Exam 2 Study Guide 6 Flashcards
How is the SC organized?
by region (cervical, thoracic, lumbar, sacral, cauda equina)
How are SC segments identified?
by same designation as their corresponding spinal nerves
1 segment = 2 vertebrae and the disc between them
What are SC segments named for?
vertebral level where they exit the vertebral canal
What structures comprise the spinal region?
all neural structures contained within the vertebrae
- spinal cord
- dorsal roots
- ventral roots
- spinal nerves (brief)
- meninges
What structures comprise the spinal cord?
- columns
- horns
- grey matter
- white matter
- rexed lamina
- fissure
- sulci
- blood supply
CSF located here
subarachnoid space
organization of motor axons exiting the spinal cord
ventral rootlets form a ventral root
dorsal root contains
sensory axons that bring info to the SC and enter it via rootlets
large diameter sensory fibers (function)
proprioception and touch info
Where are large diameter sensory fibers found?
medially
small diameter fibers (function)
pain and temperature
Where are small diameter sensory fibers found?
laterally
Dorsal horn processes:
sensory info
Lateral horn processe:
autonomic info
Ventral horn processes:
motor info
Most of the gray matter of the SC is composed of
spinal interneurons
Where are lateral horns found?
T1-L2 segments
What is a spinal nerve?
joining of a dorsal and ventral root in the IV foramen
carry all sensory and motor of a single spinal segment
What are Rexed’s laminae?
functionally and structurally distinct areas of spinal cord gray matter
tract: Contralateral fractionation of movement, particularly of hand movements
lateral CST
tract: Control of neck, shoulder and trunk muscles
medial CST
tract: Facilitates contralateral upper limb extensors
rubrospinal
tract: Facilitates postural muscles and gross limb movements
reticulospinal
tract: Adjusts activity in neck and upper back muscles
medial vestibulospinal
tract: Ipsilaterally facilitates LMN’s to extensors, inhibits LMN’s to flexors
lateral vestibulospinal
tract: Enhances the activity of interneurons and LMN’s in SC
ceruleospinal/raphespinal
recurrent inhibition causes inhibition of these groups
- agonists
- synergists
Loss of Renshaw cells creates
loss of fine motor skills
