Lecture 18 Flashcards
Where is the spinal cord found? Where does it begin and end?
Found within the spinal cavity (within the vertebrae), begins at foramen magnum at the base of the skull and ends at the inferior border of the L1 vertebrae
How can you differentiate the two sides of the spinal vertebrae?
Dorsal(posterior) side is bumpy, ventral(anterior) side is more rounded.
What is the spinal cord surrounded by and what are its end and extension parts known as?
The spinal cord is enclosed within a meningeal sack filled with cerebrospinal fluid, it ends in a tapered cone known as the conus medularis, the filium terminale then extends from this cone to the end of the spinal cord (coccygeal area). Also has the Cauda Equina axons extending from the bottom.
What are the major purposes of the Filium Terminale
- Anchors the spinal cord
2. Extends the meninges.
How many nerves are in each section? compare this to the amount of vertebrae which make up these regions. At what point do the nerve regions begin and end?
Cervical = 7, Thoracic = 12, Lumbar = 5, Sacral = 5, the vertebrae have C = 8, Thoracic = 12, Lumbar = 5, Sacral = 5.
The cervical starts at C1 and ends at C8.
The thoracic starts between T1 and T2 and ends at T10 (the axons leave between T1 and L1).
The Lumbar starts at T10 and finishes at T12 (axons betwen L1 and L5).
Sacral starts at T12 and end at L1 (axons from S1 to coccygeal zone).
What spinal nerves are found after the conus medularis?
Those found within the Cauda Equina, these spinal nerves exit at the lumbar, sacral and coccygeal level.
What is the difference between a sulcus and a fissure?
A fissure is a deep sulcus.
What are the main(unspecific) internal features of the spinal cord?
Grey matter(the cell bodies), white matter(the axons), a posterior median sulcus, an anterior median fissure, and the central canal, these are in the CNS. Also has a dorsal root ganglia on either side laterally, which are in the PNS.
What structures do the grey matter and white matter make up?
Grey matter forms the horns of the spinal cord and the white matter forms the Columns, these both have a dorsal and ventral side.
Nerves extending out from the horns have their cell bodies in the _________ nervous system and their axons in the _______ nervous system
Nerves extending from the horns have their cell body in the central nervous system and their axons in the peripheral nervous system
Where do afferent nerves have their cell bodies and what is the typical morphology?
The cell body is in the dorsal root ganglia, these neurons are typically unipolar.
Which part of the horns receives signals and which part outputs signals?
The dorsal horns receive signals as they are the afferent(sensory) part of the spinal cord grey matter, the ventral horns output signals as they are the efferent(motor) part of the spinal cord grey matter.
what direction does information flow through the white matter?
The lateral columns send signals in both directions (afferent and efferent), the dorsal sends only afferent, the ventral sends only efferent.
Where do the two types of efferent signal (somatic and autonomic), leave the spinal cord
Somatic: motor neurons in ventral horns of spinal cord
Autonomic: motor neurons in the lateral/ventrolateral horns of the spinal cord.
What happens to the spinal nerves once they leave the spinal column?
Breaks into two branches, a dorsal side(dorsal ramus) and a ventral side (ventral ramus), also splits off into two sympathetic rami, one on each side (these allow communication with the sympathetic chain ganglia).
