CSF and Meninges

Question 1

What is the main function of the meninges?

Answer 1

PROTECTION

Question 2

What are the two layers of the dura mater?

Answer 2

Periosteal layer
inner meningeal layer

stuck together and very tightly tacked onto the skull

Question 3

Special places where two dura layers come apart to form?

Answer 3

sinuses

Question 4

What forms falx and tentorium dural infoldings?

Answer 4

meningeal layer

Question 5

Which mater layer is trabecular?

Answer 5

Arachnoid! Contains projections and space that contains CSF

Question 6

What is the pia layer consisted of?

Answer 6

Single layer of cells that wrap around entire brain…single of layer of epithelium

Question 7

Where does the dural layers end?

Answer 7

periosteal ends at foramen magnum

meningeal continues to go down with spinal cords

Question 8

Spinal cord ends? Dural sac?

Answer 8

Spinal ends at L1
dural sac ends around S2 (contains nerves that have come out of spinal cord but haven’t exited vertebral column…cauda equina)

Question 9

What does the epidural space along vertebrae contain and why is it importance?

Answer 9

Nerves leaving spinal cord, important for placement of epidural anesthesia and good place for spinal tap

Question 10

Names and number of ventricles?

Answer 10

Lushka (2 lateral)
megendi (1 medial)

all 3 communicate with cisterna magna

Question 11

Functions of CSF

Answer 11

• provides buoyancy to brain (less traction on nerves and vessels)
• dampens effects of trauma
• provides stable ionic environment
• removes metabolites from brainn extracellular fluid

Question 12

composition of CSF

Answer 12

150 cc present, about 500 cc/day made,

clear low viscosity

very little protein

less glucose than serum

acellular

THINK CLEAR AND LOW, like water…can get headaches of too much drained after LP

Question 13

What makes the CSF?

Answer 13

Choroid plexus. Little stringy fronds of vascularized tissue that are present in ventricles Leaky fenestrated capillaries that uses CARBONIC ANHYDRASE for production…actively transports ions

Question 14

What is the blood CSF barrier?

Answer 14

Tight junctioned epithelium that filters large molcules like proteins

Question 15

Flow of CSF starting from lateral ventricles

Answer 15

lateral ventricles > foramen of Monro (2) > 3rd ventricle > cerebral aqueduct > 4th ventricle > magendie and luschka (2) > cisterna magna > cortex, spinal canal > along nerve sleeves > arachnoid villi granulations > superior saggital sinus >jugular veins

Question 16

What moves CSF?

Answer 16

ependymal cilia

Question 17

target of LP

Answer 17

L3/L4/L5

Question 18

Path of needle in LP?

Answer 18

Skin > subcutaneous > supraspinous ligament > ligamentum flavum (stop here for epidural anesthesia) > dura/arachnoid (stop here for CSF drainage)

Question 19

Meningitis?

Answer 19

Inflammation or infection of meninges

Question 20

What is aseptic meningetis?

Answer 20

Non-bacterial/non neutrophilic meningitis

Question 21

Signs of meningitis?

Answer 21

Headache, fever, neck stiffness, photophobia, encephalopathy

Question 22

How to Dx meningitis?

Answer 22

LP to analyze CSF and see a high WBC count and protein in CSF

Question 23

Features of meningiomas?

Answer 23

Benign, slow growing, asymptomatic, generally good prognosis

Question 24

Types of meningeal bleeds

Answer 24

epidural, subdural, subarachnoid

Question 25

Features of epidural hematoma

Answer 25

bleed in between skull and periosteal layer of dura. Consequence of traumatic rupture of MENINGEAL ARTERIES…acute

Question 26

Features of subdural bleed

Answer 26

Occur under dura, outside arachnoid. consequence of trauma to bridging VEINS (but can be chronic also , can be acute or chronic

Question 27

Features of subarachnoid bleeds?

Answer 27

occurs deeper in brain substance, can happen traumatically but usually due to ANEURYSMAL rupture of cerebral arteries. (Associated with thunderclap headache), acute

Question 28

What is hydrocephalus?

Answer 28

Obstructive process that results in dilation of CSF spaces (dilated ventricles or anywhere where CSF travels)

Water. Head. Get it.

Question 29

Communicating vs non-communicating hydrocephalus?

Answer 29

communicating - all places carrying CSF are still normally connected, but have problem draining (i.e. scarring of arachnoid villi)

non communicating - doesn’t communicate with rest of CSF
I.e. scarring of aqueduct while ventricles keep making CSF

Question 30

What can increase intracranial pressure?

Answer 30

Diffuse, focal edema (brain)
hydrocephalus, meningitis (CSF)
blood, venous clot (blood)
extra stuff (tumor or abess)

Question 31

Signs of increased intracranial pressure

Answer 31

headache, vomiting, bradycardia and hypertension, papilledma

Question 32

What does elevated protein in CSF indicate?

Answer 32

infection or inflammation, Guillan Barre syndrome, MS

Question 33

What do elevated WBCs and low glucose indicate?

Answer 33

infection, inflammatoin, neutrophils in bacterial meningitis, aseptic process

Question 34

What do elevated RBCs indicate?

Answer 34

Subarachnoid hemorrhage, hemorrhagic meningitis

Question 35

Normal color of CSF?

Answer 35

clear

Question 36

Xanthochromia

Answer 36

yellow CSF, old blood (Hb turned into bilirubin)

Question 37

Functions of blood-brain-barrier (BBB)

Answer 37

• keep plasma toxins out of brain
• block tiny oscillations of plasma ions
• keep plasma proteins and growth factors out
• keep NTs from going in or out of brain

GANDALF WITH STAFF YOU SHALL NOT PASS

Question 38

What forms BBB?

Answer 38

unique capillaries. Tight junctions in endothelial cell, processes of ASTROCYTES, capillary basement membrane

Question 39

What parts of brain lack BBB?

Answer 39

Area postrema - needs to sense toxins so you can vomit

OVLT - needs to sense ions and osmolar changes in order to influence ADH production

Question 40

What determines what passes through BBB?

Answer 40

Lipid solubility (hydrophobicity)…

if too fast, carrier mediated transport

if too slow, albumin bound