Meninges & CSF

Question 1

Two layers of dura mater

Answer 1

Meningeal and periosteal

Question 2

Where does periosteal layer end?

Answer 2

Foramen magnum

Question 3

Where in the brain is CSF?

Answer 3

subarachnoid space

Question 4

Through what structures does CSF enter venous sinuses?

Answer 4

Arachnoid villi/granulations

Question 5

What veins cross arachnoid, subdural, and meningeal dura to empty into sinuses?

Answer 5

Subdural bridging veins

Question 6

Where should you perform a lumbar puncture for adults and children?

Answer 6

Under L3 - adults

Under L4 - children

Question 7

What is the epidural space used for? What structure do you cross?

Answer 7

Epidural block - anesthesia

Ligamentum flavum

Question 8

4 functions of CSF

Answer 8

1. Buoyancy to brain
2. Dampens effects of trauma
3. Stable ionic env
4. Removes metabolites from brain ECF

Question 9

What color is normal CSF? Glucose level? Protein level? Cells?

Answer 9

Clear - low protein and glucose, acellular

Question 10

What structure makes CSF? What type of endothelium does it have?

Answer 10

Choroid plexus - fenestrated, leaky capillary endothelium

Question 11

What enzyme is needed for CSF production?

Answer 11

Carbonic anhydrase

Question 12

What cells have cilia to move CSF along?

Answer 12

Ependymal cells

Question 13

Trace flow of CSF starting from choroid plexus.

Answer 13

Choroid plexus –> lateral ventricles –> foramina of Monro –> third ventricle –> cerebral aqueduct of Sylvisu –> fourth ventricle –> foramina of Luschkas and Magendie –> cisterna magna –> spinal cord and brain –> arachnoid villi –> venous system

Question 14

Inflammation or infection of meninges

Symptoms?

Answer 14

Meningitis

Headache, fever, neck stiffness, photophobia, encephalopathy

Question 15

Benign, slow growing, asymptomatic tumor of meninges

Answer 15

Meningioma

Question 16

Lens-shaped bleed often caused by damage to MMA due to trauma

Crosses cranial sutures?

Answer 16

Epidural bleed

Can’t cross

Question 17

Crescent-shaped bleed often caused by trauma to bridging veins

Crosses cranial sutures?

Answer 17

Subdural bleed

Can cross sutures, but not midline

Question 18

Diffuse bleed commonly caused by trauma or aneurysmal rupture

Answer 18

Subarachnoid bleed

Question 19

Blocked CSF flow

What are the two types?

Answer 19

Hydrocephalus

Non-communicating (obstructive)

Communicating (impaired absorption)

Question 20

What are symptoms of increased intracranial pressure (ICP)?

Answer 20

Headache, vomiting, Cushing’s reflex, bradycardia, HTN, papilledema

Question 21

What can cause ICP (increased intracranial pressure)?

Answer 21

Diffuse or focal edema in brain, hydrocephalus, meningitis, bleeds, tumors, abscesses

Question 22

What does increased protein levels in CSF indicate?

Answer 22

Infection or inflammation (Abs from GBS or MS for example)

Question 23

What does increased white cells and decreased glucose in CSF indicate?

Answer 23

Infection or inflammation

Neutrophils - bac. meningitis
Lymphocytes - aseptic process

Question 24

What does increased red cells in CSF indicate?

Answer 24

Subarachnoid hemorrhage, hemorrhagic meningitis (HSV)

Question 25

Functions of blood-brain barrier?

Answer 25

Keep plasma, toxins, proteins, growth factors, NT’s in and out

Keep stable ionic environment

Question 26

What three layers form the blood-brain barrier?

Answer 26

Tight junctions in endothelial cells, foot processes of astrocytes, capillary basement membrane

Question 27

Name two areas of the brain that do NOT have a BBB and their function:

Answer 27

1. Area postrema (senses toxins, causes vomiting)

2. OVLT (organum vasculosum of lamina terminalis) - senses osmolar changes, makes ADH decisions

Question 28

What property determines if something can cross BBB?

What must be used if transport is too fast? If too slow?

Answer 28

Lipid solubility/hydrophobicity

Too fast: Carrier-mediated transport

Too slow: Albumin-bound