lecture 19 Flashcards
Where is the foramen magnum??
at the bottom of the cranium that is a hole for the spinal cord to attach into.
Where does your spinal cord end?
The spinal cord ends at the inferior border of the 1st lumbar vertebra (L1)
What does the meningeal sack do?
That contains the spinal cord within the vertebral cavity or the canal that the vertebra form.
Is the meningeal sack filled with fluid?
Yes
At the end of the spinal cord there is a tapered cone called what?
Conus medularis which is non-neural tissue.
What is connective tissue that runs off from the Conus Medularis called?
Filum terminale which means terminal filament.
What does the filum terminale do?
It connects the tip of the spinal cord to the very end of the sack of meniges that the spinal cord sits in. It basically anchors the spinal cord.
Why does the filum terminale attach to the meningeal sack?
So the spinal cord doesn’t loosely hang around and hit the walls of the sack and damage the spinal cord, it keeps it in place.
How many segments does the spinal cord have?
31 segments
What comes of each segment in the spinal cord?
One pair (left and right) spinal nerves
How many cervical spinal nerves are there?
There are 8 cervical vertebrae
Where do spinal nerves exit the vertebral column?
Spinal nerves exit the vertebral column at the level appropriate to their origin.
What is at the end of the spinal cord?
A large collection of long nerves called Cauda Equina
What is the sulcus
Means furrow
What is fissure?
A deep sulcus
Where is the median sulcus found?
On the dorsal side in little furrows
Where is the median fissure found?
It is found on the anterior view of the spinal segment, large furrow
What is grey matter? and where is it found?
Collection of cell bodies in the cerebral cortex and its right in the middle of the spinal cord.
What is white matter? and where is it found?
White matter is made out of axons/ contains axons and is everything outside of the grey matter.
Where is the central canal?
In the centre of the spinal cord/ segment
What is the whole segment called?
CNS
What is the cords on the outside of the segment apart of?
PNS
If you split the segment through the middle, what is each half of the grey matter called?
Dorsal gray horn and lateral gray horn
What is the dorsal, lateral and ventral white columns?
They are all columns of axons.
Label the PNS roots and ganglion
Ventral and dorsal nerve root which are made out of axons, called the dorsal root ganglion which is made out of cell bodies.
Where is the spinal nerve?
Coming off the nerve roots past the ganglion where they join.
What does the dorsal side mostly concern itself with?
Afferent information so ascending or sensory information comes into the spinal cord from the outside of the body into the dorsal nerve root. PNS into CNS
What does the ventral side mostly concern itself with?
Efferent information so decesending/ motor. From CNS into PNS
Where does the efferent motor information leave from?
Leaves through ventral rods, motor commands to effectors in the body.
Where are the somatic motor neurons?
They are cell bodies in the ventral horn
Where are the autonomic motor neurons?
They are cell bodies in the lateral horn.
What would happen if the cell body was damaged?
Paralysis of muscles, supplied by spinal nerves from this level on same side only.
Where are the cell bodies of sensory neurons?
They are in dorsal root ganglion
Where are dendrites?
Out in the body they contain receptors for sensory stimulus
What does the axon for flow of information into the spinal cord look like?
Axons enters the spinal cord through dorsal roots.
What happens if you damage the spinal cord on the dorsal side?
Loss of sensation from regions of the body supplied by spinal nerves from this level, on same side only.
What happens to the spinal nerves once they leave the spinal column?
Spinal nerve splits into a dorsal ramus and ventral ramus. Also rami communicantes and symapthetic ganglion
What does dorsal ramus do?
Dorsal ramus which is efferent to back and contains both sensory and motor information to and from the back.
What does ventral ramus do?
Efferent information going out into the body and afferent coming from the ventral part of the body.
Where does the parasympathetic nervous system travel?
Through the ventral ramus
Where does the symapthetic nervous system travel through?
Goes through rami communicates, symapthetic ganglion and sympathetic nerve out into the body to make contact with the body.
Are axons unmyelinated or myelinated in a peripheral nerve?
Individual axons may be myelinated or unmyelinated, so both
What are axons covered with in peripheral nerves?
Endonerium
How are nerves protected in the body?
They are bundled into peripheral nerves.
What do endonurium covered axons bundle together to form?
Fascicle
What are fascicles covered with?
Fascicles are covered with perineurium
What are fascicles bundled with blood vessels called?
Nerve
What are nerves covered by?
Epineurium, a dense fibourus covering
What are a bundle of axons in the CNS called?
Tract
