1.4

Question 1

Layers and spaces of the meninges

Answer 1

1. Skull
2. Epidural space
3. Dura mater
4. Subdural space
5. Arachnoid mater
6. Subarachnoid space
7. Pia mater
8. Brain

Question 2

Special structures of the cranial dura

Answer 2

Dural folds create separations between parts of the brain:
- falx cerebri: separate R and L cerebral hemispheres
- tentorium cerebeli: occipital from cerebellum
- falx cerebelli: separates R and L cerebellum
- diaphragma sella: diaphragm over hypophyseal fossa formed by meningeal dura layer

Question 3

Cranial arachnoid mater

Answer 3

Thin layer with trabeculae that attach it to the pia mater
Avascular

Question 4

Cranial arachnoid mater and CSF

Answer 4

Subarachnoid space is filled with CSF.
It enlarges in some areas to form cisterns.

Question 5

Arachnoid granulations

Answer 5

Arachnoid vili that protrude into the dural sinuses.
A group of villi = granulation
Transport much of the CSF into the venous circulation.

Question 6

Cranial pia mater

Answer 6

Thin, usually only one cell deep
Vascular
Adheres to brain tissue
Acts as barrier
- degrades neurotransmitters
- separates subarachnoid matter from brain tissue

Question 7

Intercranial hemorrhages

Answer 7

Question 8

Spinal pia

Answer 8

Forms special structures
- filum terminale

Question 9

Venous sinuses

Answer 9

Formed by dura mater
Collect blood from brain and scalp (via emissary vv.)
Drains into internal jugular vv.

Question 10

Major dural sinuses

Answer 10

Superior sagittal
Inferior sagittal
Straight
Confluence of sinuses
Sigmoid sinus

Question 11

Cavernous sinus

Answer 11

Joins several sinuses deep in the cranium
Can be site of infection and embolus

Question 12

Cavernous sinus thrombosis

Answer 12

Often related to adjacent infection

Question 13

Dural venous sinus

Answer 13

Separated layers of dura
Venous circulation

Question 14

Ventricles of the brain

Answer 14

Ependymal cells line the cavities
Contains choroid plexus which produces CSF

Question 15

R and L lateral ventricles

Answer 15

In the cerebral hemispheres
Largest of the ventricles

Question 16

3rd and 4th ventricles

Answer 16

Along the midline

Question 17

Interventricular foramen

Answer 17

AKA foramina of monro
Lateral ventricles to 3rd ventricle

Question 18

Cerebral aqueduct

Answer 18

AKA aqueduct of sylvius
3rd ventricle to 4th ventricle

Question 19

Median and lateral apertures

Answer 19

Median - foramen of magendie
lateral - foramina of luschka

From 4th ventricle to subarachnoid space

Question 20

CSF

Answer 20

Clear, colorless
Circulates through ventricles and within subarachnoid space
Returns to venous circulation through arachnoid villi

Question 21

CSF circulation

Answer 21

Ventricles –> subarachnoid space –> dural sinuses/ venous circulation

Question 22

Blood brain barrier

Answer 22

Protects the brain
- vascular cells
- astrocytes
- microglia
- basal lamina

Question 23

2 main arteries of the intracranial structures

Answer 23

Internal carotid aa
Vertebral aa

Join together to create the Circle of Willis

Question 24

Vertebral artery course

Answer 24

Through transverse processes of cervical spine
Gives branches to spinal arteries
Join to form the basilar artery

Question 25

Basilar artery

Answer 25

Primarily supplies posterior cerebral a. Gives rise to - pontine aa - cerebellar aa

Question 26

Circle of Willis

Answer 26

Gives rise to - anterior cerebral a - middle cerebral a - posterior cerebral a

Question 27

Cerebral arterial supply

Answer 27

3 branches of the Circle of Willis supply most of the cerebral hemispheres

Question 28

Venous drainage of the CNS

Answer 28

We have superficial (external) and deep (internal) cerebral veins. Much of our venous drainage involves venous sinuses. Venous drainage has multiple paths, but ultimately the majority of the cranial blood flow empties into the internal jugular vein.

Question 29

CSF circulates within which space?

Answer 29

subarachnoid space, ventricles of the brain, and central canal of the spinal cord

Question 30

Which layer of meninges forms the dural sinuses?

Answer 30

meningeal layer of the cranial dura mater

Question 31

What do the venous sinuses do?

Answer 31

Collect blood from the brain and form emissary veins and also receive CSF from the subarachnoid spaces

Question 32

Where do venous sinuses empty their contents?

Answer 32

the superior jugular bulb of the internal jugular vein

Question 33

Where is CSF made?

Answer 33

choroid plexuses of the ventricles of the brain

Question 34

What is the function of CSF?

Answer 34

- forms a protective fluid cushion for the brain and spinal cord and is a recipient of brain metabolites - immunological defense of the brain - maintenance of normal pH of the brain and spinal cords environment - reducing pressure of the brain

Question 35

Internal carotid artery

Answer 35

The internal carotid artery, one of the paired terminal branches of the common carotid artery, forms numerous branches supplying the brain and participated in the formation of the cerebral arterial circle of Willis.

Question 36

80% of cerebral blood flow comes from ___ and 20% comes from___.

Answer 36

internal carotid; vertebral arteries