Lecture 18: Anatomy and Function of the Spinal Cord and Spinal Nerves Flashcards
Where does the spinal cord start?
At the Foramen magnum, the big hole at the base of the skull.
Where does the spinal cord end?
The inferior border of the first lumbar vertebra.
What is the spinal cord surrounded by?
It’s within a sac that fits inside the spinal cavity containing spinal fluid. (Within vertebrae)
What are the anterior and posterior sides of the spine called?
Ventral (anterior) and dorsal (posterior).
The spinal cord ends in a tapered cone. What is this called?
Conus medularis
What is the meninges?
3 layers of protective tissue surrounding the brain and spinal cord.
What is the roles of the Filium terminale?
Extends from the conus medullaris to the end of the spinal cavity, anchoring the spinal cord - an extension of the meninges.
At what vertebral level does the spinal cord end?
Around the L1 / L2 vertebral level.
What are the divisions of the spinal cord?
Cervical (C1-C7)
Thoracic (T1-T12)
Lumbar (L1-L5)
Sacral (S1-S5)
Which nerves make up the Cauda equina?
Spinal nerves that exit the spinal cavity inferior to the end of the spinal cord.
What is Grey matter and White matter?
Grey matter is cell bodies and white matter is myelinated axons.
What is a sulcus and a fissure?
A sulcus is a furrow, a fissure is a deep sulcus.
Which is deeper, the posterior median sulcus or the anterior median fissure?
The anterior median fissure.
What type of matter do the dorsal and ventral columns consist of?
White matter.
What type of matter do the dorsal and ventral horns consist of?
Grey Matter.
Are the dorsal and ventral nerve roots part of the PNS or CNS?
PNS
Which parts of the spinal cord does information travel up, and down?
(roots and horns)
Afferent, sensory info goes up the dorsal root and dorsal horn. Efferent, motor, info comes down the ventral horn and ventral root.
Are ventral root axons myelinated?
Yes.
What type of matter are the spinal cord columns made of?
White matter.
What direction is information travelling in the lateral, anterior and posterior columns of the spinal cord?
Posterior: Afferent
Anterior: Efferent
Lateral: Both.
What type of neurons leave the spinal cord by the ventral horns?
Somatic motor neurons.
What type of neurons leave the spinal cord by the lateral horns?
Autonomic
What would happen if somatic motor neurons were damaged?
Paralysis - muscles won’t contract.
What is the dorsal root ganglion?
The cell bodies of sensory neurons.
What would happen the dorsal horn of the spinal cord was damaged?
Loss of sensation. No sensory info.
What is a spinal nerve?
A combination of dorsal and ventral nerve roots - 2 way flow of information. Also called ‘mixed nerves’.
What happens to spinal nerves when the leave the spinal column?
The break back into two branches - ventral ramus and dorsal ramus.
What does ramus mean?
Branch
Are PNS nerve axons myelinated or not?
Some are, some aren’t.
Explain the structure of a peripheral nerve, in terms of their coverings and bundles.
Axons may be covered in myelin, which are covered in endoneurium. These covered axons are bundled to form fascicles, which are covered in perineurium. These fascicles are bundled, with blood vessels, to for a nerve. Nerve is covered in epineurium.
What is a tract?
Bundles of nerves in the CNS
