Meningeal CSF

Question 1

What composes the leptomeninges?

Answer 1

Pia + Arachnoid

Question 2

What are the fibers of the ARACHNOID that extend onto the brain & attack to PIA?

Answer 2

TRABECULAE

Question 3

What are the 3 meningeal coverings?

Answer 3

1. Dura
2. Arachnoid (forms the barrrier to not let anything from DURA into cranial cavity)
3. PIA

Question 4

What meningeal layer:

1. Provides mechanical strength
2. Has no spaces on either side
3. contains VENOUS SINUSES
4. Has its own blood supply
5. Pain sensitive

Answer 4

DURA

Question 5

What innervates the dura?

Answer 5

Front = TRIGEMINAL N.

Back of Skull = Cervical Nerves (C1, C2)

Question 6

What part of the dura separates the left & right hemisphere? Which part of the dura houses the Cerebellum?

Answer 6

1. Falx Cerebri

2. Tentorium Cerebelli

Question 7

What is found within the Tentorial Notch?

Answer 7

BRAINSTEM

• how brainstem connects with brain

Question 8

Where does CSF drain into?Through what structure of the Arachnoid Mater?

Answer 8

1. VENOUS sinuses

2. Arachnoid VIlli

Question 9

How would a skin infection enter through the sinus pathways?

Answer 9

EMISSARY VEINS

Question 10

What is the first barrier? Second?

Answer 10

Arachnoid

Pia

Question 11

What suspends the brain?

Answer 11

Arachnoid Trabeculae

Question 12

Where do cerebral arteries and veins travel?

Where is this space found?

Answer 12

SUBARACHNOID SPACE

• space found between ARACHNOID & Pia and is filled with CSF

Question 13

What covers the surface of the brain?

Answer 13

PIA MATER

• abuts against astrocyte feet at surface of CNS

Question 14

Where in the body is the PIA covering thickened? What are these 2 places in this region called?

Answer 14

1. SPINAL CORD

2a. Denticulate Ligament
- anchor spinal cord to arachnoid

2b. Filum Terminale
- ancor spinal cord to spinal dural sheath

Question 15

Where is the inner layer of cranial dura continuous with the spinal dural sheath?

Answer 15

FORAMEN MAGNUM

Question 16

Where is there an epidural

space? Where does the spinal dura & arachnoid end?

Answer 16

SPINE
- outside vertebral bodies & cranial cavity

• between periosteum & dura
  2. END AT L1/L2

Question 17

What connects the Lateral Ventricles to the 3rd Ventricle? The 3rd ventricle to the 4th?

Answer 17

1. Interventricular Foramen (Foramen of Monroe)

2. Cerebral Aqueduct

Question 18

Where does the 3rd ventricle open? Cerebral Aqueduct? 4th?

Answer 18

1. THalamus
2. Midbrain
3. CEREBELLUM

Question 19

How does CSF exit the 4th ventricle?

Answer 19

2 Lateral and 1 median Aperture

1. Foramen of Luschka
2. Foramen of Magendie

Question 20

What are the 3 places CSF is made? What absorbs it in these locations?

Answer 20

1. CHOROID PLEXU (main)
2. Capillaries
3. Metabolic

ALL absorbed by ARACHNOID VILLA

Question 21

What is the Blood-CSF barrier? What are the 3 main components?

Answer 21

CHOROID PLEXUS

1. Pia
2. Capillary - fenestrated*
   = vascular**
3. CHOROID EPITHELIUM
   - ependymal cells w/ tight junctions

Question 22

What type of cells line the ventricles?

Answer 22

EPENDYMAL CELLS (choroid epithelium) w/ TIGHT JUNCTIONS*

• water transported ACTIVELY

Question 23

What is found outside the pia?

Answer 23

Subarachnoid space

Question 24

What are the 3 areas Choroid Plexus is made?

Answer 24

1. Lateral Ventricle
2. 3rd Ventricle
3. 4th Ventricle

• requires EPENDYMAL cells to be close to pia

Question 25

What is the step by step route of CSF? (5 steps)

Answer 25

1. made in CHOROID PLEXUS of the VENTRICLES 2. exits via Foramen of Luschka + Foramen of Magendie (median & lateral) 3. move into CISTERNs 4. through TENTORIAL NOTCH 5. through ARACHNOID VILLI into Dural VENOUS SINUS

Question 26

Where does CSF end up? How?

Answer 26

VENOUS SINUSES - through ARACHNOID VILLI

Question 27

What 2 areas is the ependyma close to the pia?

Answer 27

Transverse Cerebellar FISSURE & LATERAL VENTRICLES

Question 28

What are the 5 main functions of CSF?

Answer 28

1. MECHANICAL SUPPORT (buoyancy) 2. Buffering system 3. COmmunication w/ extracellular fluid 4. Sink for substances to be absorbed/reabsorbed 5. SPREAD OF "neuroactive" HORMONES = a TRANSPORT SYSTEM

Question 29

What is the pathological state of excessive CSF accumulation in ventricles or subarachnoid spaces?

Answer 29

HYDROCEPHALUS

Question 30

What is Hydrocephalus usually determined by?

Answer 30

Hydrostatic Pressure | insufficient absorption; classical hypothesis

Question 31

What are the 2 main circumventricular organs? Which is secretory and which is sensory?

Answer 31

1. Area Postrema = SENSORY | 2. Neurohypophysis = SECRETORY

Question 32

What makes Circumventricular Organs unique?

Answer 32

Lack a blood brain barrier = NO TIGHT JUNCTIONS (made of neurons, glia, ependymal cells, leptomeningeal, and vascular elements)

Question 33

What specialized cells overly the ependymal cells in CIRCUMVENTRICULAR organs?

Answer 33

Tanycytes - barrier between organ & ventricular CSF

Question 34

What are the common areas of meningeal bleeding/ abnormal spaces?

Answer 34

1. Epidural 2. Subdural 3. Subarachnoid (aneurisms*) 4. Intraparenchymal (in brain) 5. Intraventricular

Question 35

What is the term for bleeding within the brain itself?

Answer 35

Intraparenchymal/ Intracerebral

Question 36

What is brain herniation?

Answer 36

develop a mass inside cavity and squeeze out CSF - due to tumor, hemorrhage, traumatic brain injury = INCREASE IN INTRACRANIAL PRESSURE

Question 37

What are common areas of herniation?

Answer 37

1. Transtentorial Hematoma 2. Subfalcine (falx pushed by hemisphere) 3. Epidural Hematoma (dura pushed away from skull)

Question 38

Laceration of which artery is the cause for an EPIDURAL HEMATOMA?

Answer 38

Middle Meningeal Artery