Meninges & Ventricles

Question 1

What are the functions of CSF? (4)

Answer 1

1. Provides buoyancy, protects against sudden movements
2. Maintains constant intracranial pressure
3. Controls extracell. fluid of brain
4. Some antibacterial properties

Question 2

What produces CSF? Where?

Answer 2

Choroid plexus in brain ventricles

Question 3

What forms the blood-CSF barrier?

Answer 3

Choroid plexus

Question 4

What is the difference between ependymal cells and choroidal epithelium?

Answer 4

Ependymal cells: adhering junctions: CSF flows into brain

Choroidal epithelium: tight junctions form the blood-CSF barrier

Question 5

What comprises the BBB?

Answer 5

Capillary endothelium and astrocyte foot processes

Question 6

What are the functions of the BBB?

Answer 6

Controls ionic environment (neurotransmission)
Protects brain from drugs/toxins
Contains transporters for glucose, proteins

Question 7

What can disrupt the BBB?

Answer 7

Infection, tumors, trauma –> may cause vasogenic edema

Question 8

What is a circumventricular organ, and what does it allow the brain to do?

Answer 8

Region where the BBB is compromised

Enables brain to respond to changes in blood chemistry

Question 9

What is the theory of sleep with CSF?

Answer 9

CSF perfusion removes metabolic waste products during sleep

Question 10

What is the flow of CSF from ventricles to subarachnoid space?

Answer 10

4th ventricle
Foramen of Magendie/Luschka
Subarachnoid space around brain/spinal cord
Arachnoid granulations
Venous Sinuses

Question 11

What are arachnoid villae?

Answer 11

small evaginations of arachnoid into sinus

Question 12

What are large arachnoid villi called?

Answer 12

Arachnoid granulations

Question 13

What is in the subarachnoid space?

Answer 13

CSF and blood vessels

Question 14

What is a cistern?

Answer 14

An enlarged area of subarachnoid space

Question 15

When is a lumbar puncture contraindicated?

Answer 15

If there is increased intracranial pressure because a tentorial or cerebellar herniation could occur

Question 16

Where do you perform a lumbar puncture?

Answer 16

Adults: L3-L4
Kids: L4-L5

Question 17

Why perform an LP?

Answer 17

1. Obtain samples of CSF

2. Introduce drugs (e.g. chemo)

Question 18

What are dural folds and what is their function?

Answer 18

Folds of inner dural layer between brain regions to create compartments in cranial cavity

Question 19

Where is the falx cerebri located?

Answer 19

In between cerebral hemispheres

Question 20

Where is the falx cerebelli located?

Answer 20

In between two hemispheres of cerebellum

Question 21

Where is the tentorium cerebelli?

Answer 21

In between the posterior cerebral hemispheres and cerebellum (brain and cerebellum separated)

Question 22

Where is the diaphragm sellae located?

Answer 22

It is the circular fold beneath the brain that covers the sella turcica

Question 23

What two compartments does the tentorium cerebelli form?

Answer 23

Supratentorial

Infratentorial

Question 24

What is the posterior fossa bounded by? What is inside?

Answer 24

Bounded by: occipital bone (base) and tentorium cerebelli (roof)
Contains cerebellum and brainstem

Question 25

What is the relationship between the brainstem and the tentorial notch?

Answer 25

The midbrain reticular formation is located there… if compressed, may cause coma

Question 26

What may increase intracranial pressure?

Answer 26

1. Tumor
2. Abscess
3. Hemorrhage
4. Edema
5. Hydrocephalus
6. Infection

Question 27

What are symptoms of increased intracranial pressure?

Answer 27

1. Headache
2. Altered mental status
3. Nausea/vomiting
4. Eyes that appear to look down
5. Papilledema: swelling of optic papilla
6. Visual loss
7. Diplopia
8. Cushing’s triad: HTN, bradycardia and irregular respirations (brainstem)
9. In kids: skull may expand

Question 28

What is hydrocephalus?

Answer 28

Condition of excess CSF

Question 29

How can hydrocephalus occur? (3 ways)

Answer 29

1. Excess CSF production
2. Obstructed flow anywhere in ventricles or subarachnoid space
3. Decreased reabsorption via arachnoid granulations

Question 30

What is communicating hydrocephalus?

Answer 30

When the lateral ventricles communicate with subarachnoid space

Question 31

What is non-communicating hydrocephalus?

Answer 31

When flow is obstructed within the ventricular system

Question 32

What are the signs of hydrocephalus in small children/infants?

Answer 32

1. Rapid head growth
2. Bulging fontanelle (soft spot) in infants held upright
3. Dilated scalp veins

Question 33

What are the symptoms of hydrocephalus in small children/infants?

Answer 33

Poor feeding
irritability
Vomiting
Lethargy
Downward eyes

Question 34

How do you relieve chronic hydrocephalus?

Answer 34

Ventriculoperitoneal shunt –> drain excess CSF into the peritoneal cavity for the body to reabsorb

Question 35

What is a Chiari malformation and what does it produce?

Answer 35

• • Congenital hindbrain anatomic anomaly which is associated with the cerebellum, brainstem or craniocervical junction that results in downward displacement of the cerebellum
• • Hydrocephalus

Question 36

What population usually experiences symptoms of a Chiari malformation?

Answer 36

Adults

Question 37

What causes symptoms of a Chiari malformation?

Answer 37

1 Compression of medulla and upper spinal cord
2 Compression of cerebellum
3 Disruption of CSF flow through foramen magnum

Question 38

What causes normal pressure hydrocephalus, and who does it occur in?

Answer 38

Elderly
Dilation of the ventricles upon MRI
May be related to reabsorption from meningitis or subarachnoid hemorrhage

Question 39

What are the symptoms of normal pressure hydrocephalus?

Answer 39

1. Gait disturbance
2. Dementia
3. Urinary incontinence: urgency, frequency or diminished frequency of the need to urinate
   NO HEADACHE!!!! (Frontal lobe symptoms)