The Nervous System Pt. 3 - Meninges and Ventricles Flashcards
What are cranial meninges and what makes up the cranial meninges?
Three protective, connective tissue coverings encircle the spinal cord and brain
1. Dura Mater (Outermost protection)
2. Arachnoid Mater
3. Pia Mater (Innermost protection)
What is the subarachnoid space? What is it known to hold?
Subarachnoid space is the space between the arachnoid & pia mater.
* Contains Cerebral Spinal Fluid (C.S.F.)
Why does the dura mater go through the fissure area?
So that C.S.F. (Cerebral Spinal Fluid) gets access to all parts of the brain
* Other mater can also go into the fissures of the brain
Dura Mater is the most superficial cranial meninge that forms a sac containing venous sinus
Arachnoid mater has fibrous attachments that connect it to the pia mater? This is also how the Arachnoid mater gets its name.
Trabeculae
What are dural folds?
Meninges (dura or other mater) following into a fissure of the brain
Only in the bigger fissures
Remember: Fissures are the split btwn. segments of the brain
What is the venous sinus?
Venous sinuses are areas for draining poorly oxygenated blood.
Superior sinus formed within dura mater
Where does the superior sagittal sinus run through?
Dural folds between the two cerebral hemispheres
Where are venous sinuses formed and what are their functions?
Form within dural folds
* Collect poorly oxygenated blood from around the brain
* Bring back to the heart
What are arachnoid granulations? Purpose?
Outcropping of Arachnoid Mater into venous sinus
* Send wastes products from the brain & old C.S.F. into venous system
Purpose of Cerebral Spinal Fluid in terms of its contribution to the brain?
C.S.F. runs in subarachnoid space and bathes the brain to keep it safe and also contributes to buoyancy
C.S.F. can be used as a marker to help N.S. (Spinal Taps)
How many ventricles of the brain are there? What are they?
4 ventricles:
2 lateral ventricles
Third Ventricle
Fourth Ventricle
What is the lateral ventricle and where is it found?
C-shaped; follow basal nuclei shape
* Connected to each other by the Interventricular foramen and the third ventricle on the thalamus
What is the third ventricle connected to and by what?
Connected to the 4th ventricle via the aqueduct of the midbrain
What is common amongst the 4 ventricles?
Contain choroid plexus which is composed of blood capillaries and specialized cuboid epithelial cells called ependymal cells
When C.S.F. is being made, plasma from blood goes through ependymal cells and C.S.F. goes into ventricles
Pathway of C.S.F. from the Lateral Ventricle
- C.S.F. made in L.V.
- Then travels to Interventricular Foramen (I.F.) to the third ventricle
- To the aqueduct and that goes to the fourth ventricle
From here there are a few places to go:
* Exit through subarachnoid space via 2 lateral aperature or 1 median aperature
OR
Straight down into the central canal which runs all the way down the spinal cord
If we make C.S.F. in the 4th ventricle you do not need to go through extra paths
* lateral and median aperature also sends C.S.F. to spinal cord cause there are meninges but Central canal sends more
