6- Spinal Cord and Tracts Flashcards
Afferent Info Streams
Local Reflexes
To cortex
To cerebellum
Info goes to all 3 streams simultaneously
Spinal Cord Ends At
Conus Medullaris at L1/L2
Cauda Equina
Collection of nerve terminals (L3-S5) caudal to the conus medullaris
Formed from lower spinal nerves descending before exiting spinal cord
Filum Terminale
Fibrous tissue connecting conus medullaris to coccyx
Made of pia mater- anchors spinal cord to vertebrae
Dermatomes
Mesoderm—-> somites
Somites retain connectivity with originating vertebral level
Somites differentiate
Result in different regions of the body connected to different parts of spinal cord
Lissauer’s Tract
Entry point of some DRG fibers
In PH
Intermediate Gray (IG)
Contains interneurons adn tract cells , some autonomic pre-ganglionic MN
Ventral Horn (VH)
Has motor neurons
Substantia Galatinosa
Superficial zone of DH
Has nerve terminal
In PH
Rexed Laminae
Defined by cellular structure
I-X
Rexed Laminae- DH
I-VI
Rexed Laminae- IG
VII
Rexed Laminae-VH
VIII-IX
Central Canal
X
Fibers of the Spinal Cord
Long ascending—> thalamus, cerebellum, brainstem
Long descending–> from cortex to spinal cord
Local propriospinal- shorter fibers that interconnect different parts of spinal cord