W2 - Barriers Flashcards
What is the bone where the brain sits in it’s depression?
Cranial fossae
What 3 bones are a part of the anterior cranial fossae?
Frontal, ethmoid, sphenoid
What 2 bones are a part of the middle cranial fossae?
Sphenoid + temporal
What 4 bones are a part of the posterior cranial fossae?
Sphenoid, temporal, parietal and occipital
What part of the cranial fossa does the brainstem/cerebellum sit in?
Posterior
What part of the cranial fossa does the temporal lobes/pituitary gland sit in?
Middle
Which part of the cranial fossa does the frontal lobes/olfactory nerves sit in?
Anterior
The dura mater is the most external + hardest meninge, how many layers does it have and what does it connect to in places?
2 - periosteal and meningeal, connects to skull in places
Which meninges have blood supply?
Dura and arachnoid maters
Where is the CSF stored and then secreted into?
Stored in ventricles and secreted into subarachnoid space
Which meninge follows all the contours of the brain and attaches to the basement membrane of the brain’s glial lining?
The pia mater`
Which dural reflection is longitudinal (vertical) and which is transverse (horizontal)?
Falx cerebri - longitudinal from cranial roof to between hemispheres, Tentorium cerebelli - transverse between cerebrum and cerebellum to side of cranium
Which out of the two dural layers is closer to the bone?
Periosteal
What is the incisure called where the brainstem (+ cerebellum) passes through?
Tentorial incisure
CSF is similar to plasma, what makes it different?
CSF has less proteins
Where do you take a sample of CSF from in a lumbar puncture?
Lumbar cistern
What 3 parts of the choroid plexus work together to produce CSF?
Endothelium, pia cells + ependymal cells
What are the four main functions of CSF?
Waste elimination, chemical communication, spatial buffer, support/protection
Why does CNS float within the CSF?
It is less dense than water/the CSF
If there is a growth on the brain, the CSF can be displaced to decrease pressure, what function of the CSF does this relate to?
Spatial buffer
CSF provides a medium for the movement of chemicals and hormones, which function of the CSF does this relate to?
Chemical communication
What is the word that describes the fact that CSF moves in phase with heart rate?
Pulsatile
What are the two things that propel movement of CSF?
Contraction/pulsation of the arteries, negative pressure in thorax during inspiration = decreased intracranial pressure so CSF moves up into space
What does the glymphatic system do?
Moves excess fluid and waste into blood
What spaces and cells do the glymphatic systems consist of?
Interstitial and perivascular spaces and astrocytes
During slow wave sleep, what happens to the interstitial space, astrocytes and waste clearance?
Astrocytes contact (decrease volume), interstitial space = 60% larger and waste clearance increases
What are two examples of toxic molecules that are drained by the glymphatic system?
Free radicals + amyloids
What two components make up the BBB?
Astrocyte end feet action and endothelial tight junctions
What are arachnoid villi?
1 way valves that allow CSF into the dural sinuses if the subarachnoid pressure is greater than in the sinuses
What causes the cisterna magna, lumbar and interpeduncular cisterns to form?
Irregularities in surface of CNS mean that pockets of CSF form
What can cross the BBB barrier unaided?
Any liposoluble substance
What are the 3 horns called in the lateral ventricles?
Frontal, occipital and temporal
Describe the pathway of CSF in ventricles
Lateral - foramina monro - 3rd vent - cerebral aqueduct - 4th vent - 2 lateral + 1 mid foramen - subarachnoid space - arachnoid villi - dural sinuses
What are the 3 cisterns called?
Interpeduncular cistern, lumbar cistern, cisterna magna
