Lec 4 Flashcards
what happens as the meninges continue into the spinal cord?
What about other layers?
- The periosteal layer fuses to the bone of the foramen magnum.
- Only the meningeal layer continues down spinal cord.
- Arachnoid mater and subarachnoid space continues
- Pia mater also continues in spinal cord
Periosteum vs periosteal layer of the dura
Periosteum covers outer layer of bones, it also continues in spinal cord.
Periosteal layer of the dura covers outside of brain.
Vertebral foramen vs intervertebral foramen
Vertebral foramen = where spin cord runs
Intervertebral foramen = space between vertebrae from side view
What are meninges?
Protective layer for the brain (PAD)
which is in the centre of the spinal cord grey or white mater, what about the brain?
Grey mater in middle of spinal cord but in brain, cortex (outside) is made of grey mater
In the spinal cord, is the pia mater fused to the arachnoid mater
no there is a subarachnoid space for cerebrospinal fluid
What is the denticulate ligament, what connect to?
What is its function?
part of pia mater that run through arachnoid mater and connect to dura.
holds spinal cord in place (cause otherwise floats in CSF)
what are the threads of nerves that go into the spinal cord called
ventral and dorsal rootlets (depending on where enter/exit)
what happens to meninges as follow nerve out of spinal cord
fuse together
where is CSF cerebrospinal fluid produced?
produced by Choroid plexus (cells) located in the ventricles (primarily lateral ventricles). Then circulate in subarachnoid space.
how does CFS enter the blood system?
Through the arachnoid granulations (there are some other places not as common/not a concern for the course)
What does the CSF do (5 things)
- Provide buoyancy to decrease pressure on brainstem
- Provide cushion for CNS
- get rid of waste metabolites
- transport hormones and nutrients
- Maintain intracranial pressure
What is the abnormal accumulation of CSF leading to pressure in the brain called?
Cause?
Hydrocephalus
Could be overproduction of CSF, blockage from bleeding or tumour etc.
Where are the two places that doctors will do a spinal tap and why?
The cisterna magna (large space containing CSF between spinal cord and cerebellum)
Lumbar cistern
Both have reservoir of CSF. The lumbar cisterna is below the spinal cord (below the conus).
define a spinal segment
portion of spinal cord that gives rise to a one spinal nerve
how many sections is the grey matter separated into and what is it called
what is the significance of the IXth lamina?
10 regions called the Rexed’s laminae
IX (9) contains all the motor nuclei and is divided into two regions: medial and lateral
what is somatotopic organization.
Ordered mapping of parts of brain or the spinal cord to body parts.
Parts of CNS correspond to control of body parts in an orderly way.
how are motor neurons for limbs organized in the spinal cord ventral horn.
medial motor neurons control proximal muscles (e.g. shoulder) whereas lateral neurons control distal muscles (such is in the hand)
