Lecture 18 Flashcards
What is the former magnum and what is its purpose?
The hole in the skull which connects the spinal cord to the brain.
Between what levels of the vertebrae column does the spinal cord exist?
Cervical 1 and lumbar 1 (C1-L1).
What is the spinal cord surrounded by?
A cavity (meningeal sack) filled with fluid and a layer of fat.
What is the tapered cone shaped structure at the end of the spinal cord (L1/L2 region)?
conus medularis.
What is the spinal cavity and where is it located?
A spinal cavity exists between the end of the lumbar level and sacral level, where there are no vertebrae located.
What is the Filum Terminale and what does it do?
A long section of bone that extends down from the conus medularis all the way to the end of the spinal cavity.
- It anchors the spinal cord
Where do the spinal nerves exit and where do they go?
- some spinal nerves exit between the cervical and thoracic levels and go to the arms and thorax.
- The spinal nerves in the L1/2 levels and below, descend down into the spinal cavity and hang there, these nerves go to the legs, pelvis and abdomen.
What is the collection of spinal nerves in the spinal cavity called that descend down from the lumbar, sacral, and coccygeal vertebral column levels called?
Cauda equina (horse’s tail).
What is the posterior and anterior parts of the vertebrae called?
Anterior = Ventral Posterior = Dorsal
What is the central nervous system of the vertebrae made up of?
Grey matter (cell bodies) + white matter (axons).
What is the peripheral nervous system of the vertebrae made up of?
Dorsal root ganglion + spinal nerve.
What is the dorsal and ventral sections of white matter called and what do they do?
White matter are axons.
Dorsal white matter - dorsal columns
Ventral white matter - ventral columns
These axons run both up and down from the brain.
What is the dorsal and ventral sections of grey matter called?
Grey matter are cell bodies.
Dorsal grey matter - dorsal horn.
Ventral grey matter - ventral horn.
Where does the peripheral nervous system start in the vertebrae?
The dorsal and ventral nerve roots.
What kind of information does the dorsal side of the vertebra take in and in which direction does it go?
- Sensory information - flowing into the CNS of the vertebrae and up towards the brain (ascending)
What kind of information does the ventral side of the vertebra take in and in which direction does it go?
- Motor information - flowing out from the brain to the CNS of the vertebrae and to muscles (descending).
Which directions does the posterior, lateral and anterior columns flow?
Posterior (dorsal) columns - flows upwards to the brain (ascending)
Anterior (ventral) columns - flows downwards (descending).
Lateral columns - flows both up and down (ascending and descending).
What kind of motor neurons are in the ventral horns and lateral/ventrolateral horns?
Ventral horns - somatic motor neurons.
Lateral/ ventrolateral - autonomic motor neurons.
What would happen if there was damage done to the somatic motor neurons in the ventral horns?
Paralysis of muscles supplied by the spinal nerves from this level, on the same side only.
What end of the spinal nerve does afferent information (sensory) enter the spinal cord?
The dorsal root.
What is the dorsal root ganglion?
Where the cell bodies of sensory neurons are located.
What would happen if the dorsal horn (grey matter) was damaged?
Loss of sensation in regions of the body innervated by neurons from this level, on the same side only.
Describe the spinal nerve and how to is split into 2 parts.
The spinal nerve is both the ventral and dorsal roots combined.
The ventral nerve root - flow of information out of the CNS.
The dorsal nerve root - flow of information into the CNS.
What happens to spinal nerves once they leave the spinal column (CNS)?
They branch off into a dorsal ramus and ventral ramus (plural= rami).
The ventral ramus communicates with the sympathetic chain via two sympathetic rami.
Describe the structure of a peripheral nerve.
- Axon
- Myelated / not myelated
- Covered by endoneurium
- A bunch of endoneurium covered axons form a fascicle
- Fascicles are covered by perineurium
- Fascicles are bundled with each other and with blood vessels to form a nerve.
- Nerves are then covered by the epineurium.
Bundles of axons in the CNS are called a tract.
