8 - Vasculature

Question 1

Three Meningeal Layers

Answer 1

Dura
Arachnoid
Pia

Question 2

Dura Mater

Answer 2

Thick, tough collagenous membrane.
Adheres to inner surface of skull AND the arachnoid mater
Contains sinuses for venous blood flow

Question 3

Arachnoid Mater

Answer 3

Thin membrane of cells interspersed with bundles of collagen.
Arteries extend and CSF flows in the space between the Arachnoid and Pia (Subarachnoid Space)

Question 4

How does CSF enter venous circulation?

Answer 4

Passively (down a pressure gradient) via Arachnoic Villi or Granulations

Question 5

Pia Mater

Answer 5

Delicate membrane that hugs the surface of CNS and consists of a single cell layer + astrocyte processes

Question 6

How are water-soluble molecules and ions blocked from crossing the BBB into the CNS?

Answer 6

Ridonkadonk numerous tight junctions on the endothelial cells lining the blood vessels.

Question 7

What can directly diffuse across the BBB?

Answer 7

Lipid-soluble molecules and gases

Question 8

How do ions cross the BBB?

Answer 8

Regulated membrane channels!
and/or
Facilitated transport (down a gradient) and energy-dependent receptor-mediated transport (up a gradient).

Question 9

Structure of a Tight Junction in the BBB

Answer 9

A group of cell adhesion molecules (Claudin, Occludin, JAM) expressed on adjacent membranes.
These homologous molecules form homotypic interactions with each other.
They are held together by cytoskeletal structures (actin, binding proteins, etc)
They exist as sheets along the cell to prevent the passage of any specific molecule between the vessel lumen and CNS

Question 10

Which transporters are on the lumen side of the BBB?

Answer 10

Glut1 (Glucose)
L-System (Leucine)
Na+
MCT1
L-System (L-DOPA)

Question 11

Which transporters are on the CNS side of the BBB?

Answer 11

Glut1 (Glucose)
LAT1 (L-System)
ATA2 (A-System)
Na/K ATPase
MCT1
L-System (L-DOPA)

Question 12

Which transporters are on both sides of the BBB?

Answer 12

Glucose Transporters
L-System
Acidic Transporters

Question 13

Which transporters are exclusive to the CNS side of the BBB

Answer 13

LAT1
ATA2
Na/K Pump

Question 14

How is Parkinson’s treated with L-DOPA?

Answer 14

L-DOPA enters endothelial cell, is converted intracellularly to Dopamine, enters CNS through transporter

Question 15

Flow of CSF - Between LV & 3V

Answer 15

Foramina of Monro

Question 16

CSF is produced where?

Answer 16

Choroid Plexus in the Lateral Ventricle, 3rd Ventricle & 4th Ventricle.

Question 17

Flow of CSF - Between 3V and 4V

Answer 17

Cerebral Aqueduct (Aqueduct of Sylvius)

Question 18

Flow of CSF - Between 4V and Subarachnoid Space

Answer 18

Foramina in 4V
Cisterns:
Superior Cistern
Cisterna Magna
Interpeduncular Cistern
Pontine Cistern
Lumbar Cistern (in caudal spinal cord)

Question 19

Flow of CSF - Between Subarachnoid Space and Sagittal Sinus

Answer 19

Arachnoid Granulations

Question 20

What happens when you develop a space-occupying lesion near the Foramina of Monro or the Cerebral Aqueduct?

Answer 20

These narrow passageways get compressed and leads to a build-up of CSF in the isolated chambers.
Hydrocephalus
Treat with a surgical shunt and/or eliminate the lesion

Question 21

Arteries supplying the Spinal Cord

Answer 21

Anterior Spinal Artery
Posterior Spinal Artery
Radicular Arteries

Question 22

What gives rise to the Anterior Spinal Artery?

Answer 22

Vertebral Arteries

Question 23

What gives rise to the Posterior Spinal Artery?

Answer 23

Vertebral Arteries

Question 24

What gives rise to the Radicular Arteries?

Answer 24

Segmental arteries off the Aorta

Question 25

Which part of the spinal cord is the least vascularized (and thus the most vulnerable to ischemia)?

Answer 25

Thoracic

Question 26

Where does the Cervical Spinal Cord get its blood supply?

Answer 26

Anterior Spinal Artery | Posterior Spinal Artery

Question 27

List the Major Branches of Posterior and Anterior Circulation from caudal to rostral

Answer 27

``` Vertebral Artery Posterior Inferior Cerebellar Artery Anterior Spinal Artery Anterior Inferior Cerebellar Artery Basilar Artery Superior Cerebellar Artery Posterior Cerebral Artery Posterior Communicating Artery Middle Cerebral Artery Interior Carotid Artery Anterior Cerebral Artery Anterior Communicating Artery ```

Question 28

Components of the Circle of Willis

Answer 28

``` PCA PComm IC/MCA ACA AComm ```

Question 29

What part of the Circle of Willis do people sometimes not have?

Answer 29

PComm (unilateral or RARELY bilateral)

Question 30

Posterior Circulation - Blood Supply of the Brainstem

Answer 30

``` Paired Vertebral Arteries PICA ASA PSA Basilar AICA SuCe PCA ```

Question 31

Middle Cerebral Artery Path/Territory

Answer 31

Branches off Internal Carotid Meanders around Insular Cortex Emerges and supplies dorsolateral aspects of Frontal & Parietal Lobes, as well as part of the Occiptial Lobe, and the superior aspect of the Temporal Lobe

Question 32

Anterior Cerebral Artery Path/Territory

Answer 32

Medial surface of Frontal and Parietal Lobes

Question 33

Posterior Cerebral Artery Path/Territory

Answer 33

Inferior surface of Temporal Lobe, Parietal Lobe and Occipital Lobe Lateral and medial surface of Occipital Lobe

Question 34

Where do the ACA and MCA anastomose?

Answer 34

Superior surface of Frontal and Parietal Lobes

Question 35

Where do the ACA and PCA anastomose?

Answer 35

Medial surface of Occipital Lobe

Question 36

Where do the MCA and PCA anastomose?

Answer 36

Lateral and inferior surface of Occipital and Temporal Lobes

Question 37

Penetrating branches of the MCA

Answer 37

Lenticulostriate Arteries

Question 38

Penetrating branches of the ACA

Answer 38

Medial Striate Arteries

Question 39

What is supplied by the Anterior Choroidal Artery?

Answer 39

Posterior parts of the internal capsule