chapter 26: meninges & CSF

Question 1

production of CSF by choroid plexus of all 4 ventricles

Answer 1

• formed by invaginations of vascular pia mater on medial surface of cerebral hemispheres
• covering layer of epithelium taken from ependymal lining of the ventricle

Question 2

the blood CSF barrier

Answer 2

formed by cells of choroid epithelium and tight junctions

Question 3

production of CSF is a complex proces

Answer 3

• water enters and leaves CSF by diffusion
• others need assistance of metabolic activity
• active transport of ions through epithelial cells
• passive movement of water to maintain osomotic equilibrium
• transporter proteins allow controlled movement of glucose and amino acids into CSF

Question 4

circulation of CSF

Answer 4

• flows from lateral ventricles into third ventricle and into fourth ventricle
• leaves ventricular systel through median and lateral apertures of fourth ventricle
• moves through spinal subarachnoid space
• flows through basal cistern and over medial and lateral surfaces of cerebral hemispheres
• movement is assisted by pulsation of arteries in subarachnoid space around spinal cord

Question 5

absorption of CSF into venous blood

Answer 5

through arachnoid villi:

• into dural venous sinuses and superior sagittal sinus
• each villi consists of thin cellular layer of endothelium of the sinus

Question 6

absorptive mechanisme of CSF into venous blood depends on …

Answer 6

• hydrostatic pressure of CSF being higher than that of the venous blood in the dural sinuses
• higher venous pressure collapses extracellular channels of villus, preventing reflux of blood into subarachnoid space

Question 7

pressure and properties of CSF

Answer 7

• volume: 80-150ml
• rate of production: total replacement several times daily
• clear and colourless
• cells = lymphocytes
• glucose level is 1/2 of that of blood
• protein content is very low

Question 8

the meninges

closest to skull -> brain

Answer 8

dura mater
arachnoid lining the dura mater
subarachnoid space with trabecula
pia mater: adheres to brain and spinal cord

Question 9

What are the dural reflections?

Answer 9

• falx cerebri
• tentorium cerebelli
• falx cerebelli
• diaphragma sellae

Question 10

periosteum

Answer 10

• cranial dura mater/ conntective tissue of dura mater is attached to it
• supplies adjoining bone

Question 11

nerve supply of the dura mater

Answer 11

• trigeminal nerve
• vagus nerve
• spinal nerves

Question 12

dural venous sinusses

Answer 12

• superior sagittal sinus
• inferior sagittal sinus
• straight sinus
• transverse sinus

Question 13

subarachnoid cisterns =

Answer 13

= regions of subarachnoid space that contain more csf

• cerebromedullary cistern : cisterna magna
• basal cisterns:
  
  • -> pontine cistern
  • -> interpeduncular cistern
  • -> cistern of the optic chiasma