12-1 Meningeal Coverings Flashcards
1) What is the leptomeninges?
2) Arachnoid mater has ___ that insert into the Brain via the ___ ____ and is the ___ Blood Barrier. What does this do for the brain?
**Dura mater is AKA _____ **
1) Leptomeninges = Pia + Arachnoid
2) Arachnoid mater has TRABECULAE that insert into the Brain via PIA MATER and is the FIRST Blood Barrier
(This SUSPENDS the Brain)
**Dura mater is PACHYMENINX **
Dura Mater normally has no ____ on either side. It contains ___ ____ which are lined with _______.
2) [T or F] Dura Mater has its OWN Blood Supply??
3) [T or F] Dura Mater is Pain sensitive??
4) What 2 Types of Dura Mater?
Dura Mater normally has no SPACE on either side. It contains VENOUS SINUSES which are lined with ENDOTHELIUM
2) TRUE - Dura Mater has OWN blood supply
3) TRUE-
Dura Mater front skull = trigeminal
Dura Mater BACK SKULL= CERVICAL NERVES
meaning…“Pain in Head” can be referred
4)
A: Falx Cerebri = Dura separating the 2 hemispheres
B: Tentorium Cerebelli = Forms over the cerebellum and separates it from intracranial cavity
Why can the Emissary Veins be potentially problematic?
Emissary Veins are located on Skull Surface & connect extracranial veins with DURA VENOUS SINUSES
—>allowing skin infections to enter skull!
A: Describe The Arachnoid mater
B: What are Subarachnoid Cisterns
C: What travels in the Subarachnoid Space [3]
D: How does CSF enter brain venous system from its origin
Arachnoid Mater
A: Avascular, multiple layer of cells that adhere to dura (barrier function) and pia (via Trabeculae)
B: Subarachnoid Cisterns= irregular Bridges over CNS surface that form CSF filled cistern “ditches”
C: Subarachnoid Space
º- CSF
º-Cerebral Arteries & VEINS
D: CSF enters brain venous system via [ARACHNOID VILLI] —–> Dura [Venous Sinus]
____ are found UNDERNEATH Pia Mater and act as the Blood Brain Barrier. Pia Mater is MOSTLY thin except in 2 places where it is THICK.
*Describe the 2 only THICK spots of Pia Mater
B: What is the [Virchow-Robin Space]
ASTROCYTES are found UNDERNEATH Pia Mater & act as Blood Brain Barrier. Pia Mater is MOSTLY thin except in 2 Places!
- [Denticulate Dentate Ligament] = THICK Pia that Anchors Spinal Cord to the Arachnoid
- *[Filum Terminale] = THICK Pia Anchoring Caudate Spinal Cord to Caudal spinal dural sheath
B: [Virchow-Robin Space] = Perivascular space allowing vessels to enter & leave brain
1) What does the Cranial Dura caudally become once it crosses the Foramen Magnum?
2) The Spinal Epidural Space is filled with what? What about the Cranial Epidural Space?
3) When does the Spinal dura and Arachnoid actually end?
1) Cranial Dura caudally becomes [Spinal Dura Sheath] after crossing Foramen MAGNUM
2) Spinal Epidural Space filled with [Vertebral Venous Plexus]. THERE IS NO CRANIAL EPIDURAL SPACE.
3) Spinal Dura & Arachnoid Mater ends at S2
A) The 3rd Ventricle is located at the _____.
B) The Lateral Lushka and Median Magendie Foramen of Ventricle ____ are used for what?
A) 3rd ventricle is located at THE THALAMUS
B) Lateral Lushka and Median Magendie Foramen of 4TH VENTRICLE are used to carry CSF to the SubArachnoid Space—>(via Arachnoid vili) travels to dura venous sinus
A: What is the % breakdown of where CSF originates from? [3]
B: Cerebral venous blood consist of _____ & _____. Explain their relationship with Brain cells
C: Is CSF transferred from the Cerebral arterial blood via Active or Passive Transport?
A: CSF Origin=
º 60% –> ChoroiD PLEXus
º 30% —-> Capillary bed
º 10% —-> metabolic
B: Cerebral venous blood consist of INTERSTITIAL FLUID(passed thru BBB from Cerebral a.) & CSF(passed thru CHOROID PLEXUS from Cerebral a.)
[Brain Cells] [Interstitial Fluid] [CSF]
C: BOTH!!
Choroid Plexus (___-___ Barrier) Plexus consist of 3 components. What are they?
- Describe the Choroid Epithelium
- How is actual CSF Fluid MADE in the Choroid Plexus of _____Ventricles
Choroid Plexus (Blood-CSF Barrier) consist of
a. Perforated Choroidal Capillary
b. Pia mater
c. Choroid Epithelium
- Choroid Epithelium = HIGHLY specialized Ependymal cells INFERIORLY in contact with Pia = connected by tight jnctions with mitochondria & numerous microvilli facing CSF
- Choroid Capillary secretes Water—>flows thru tight junctions of [Choroid Epithelium]—>HIGHLY FILTERED into Ventricles as STERRRRILE CSF!
—>Happens in Lateral, 3rd and 4th Ventricles
A: Describe the 5 steps of FLOW for CSF
B: What Structure is responsible for REabsorbing CSF and Venous Drainage?
1st: CSF Made in Ventricles in Choroid Plexus
2nd: Travels downward & Flows OUT Lateral Lushka & Median Magendie Foramen of 4TH VENTRICLE
3rd: Goes into Subarachnoid space and [Cistern]
4th: Goes thru Tentorial notch
B: [Superior Sagittal Sinus]
1) What should you expect to find at the [Transverse cerebral fissure]?
2) What other fissure do you find similar to this?
1) [Intraventricular foramen of Monroe] opening into 3rd ventricle with ependymal cells inferiorly contacting Pia mater = Choroid Epithelium —> CSF transfer
2)
Choroidal Fissure
A: You make ___ ml of CSF a day with a total amount being ____ ml. What is the function/job of CSF?
B: CSF and Blood are similar. What are the only 2 things CSF has MORE than Blood in?
C: What are the 4 things CSF and Blood both about equally have in common?
You make 500 ml/day of CSF —->with Total = 150 ml.
Function of CSF:
1) Buoyancy and Mechanically supports brain
2) Spatial “buffering”
3) enables communication w/xtracellular fluid
4) A “Sink” for neural trash substances
5) Route for neurohormones to get around
B: CSF > Blood *Mg & Creatinine ------------------------------------------------------------------------------------ C: CSF = Blood -Na+ -Cl- -HCO3- -Osmolarity
1) What is Hydrocephalus?
2) What is the “CLASSICAL Hypothesis” behind it? [3]
3) What is the “NEW Hypothesis” behind it?
1) Dz characterized by excessive accumulation of CSF inside ventricles or subarachnoid space
2) “CLASSICAL hypothesis” = Dz is 2º to
impaired CSF circulation / Insufficient REabsorption / CSF over-secretion
3) “NEW hypothesis” = Dz 2º to hydrostatic & osmotic forces between CSF, interstitial fluid & blood capillaries
A: Circumventricular Organs consist of ____[5] elements around the ___ & ___ Ventricle and lack a ____
B: What is the purpose of the Circumventricular organs? [2]
D: What are the 3 Types of Secretory CO?
A: [Circumventricular Organs] consist of neurons, glia, ependymal cells, leptomeningeal & Vascular elements tht lack a 3rd & 4th Ventricles and lack a BBB
B: Purpose=
1. acts as “Communication” between blood, brain parenchyma & CSF
2. Critical to sodium/water balance, CV regulation, energy metabolism & immunomodulation
————————————————————————————
C: Sensory CO
•AREA POSTREMA*
•subfornical organ
•vascular organ
•lamina terminalis*
————————————————————————————
D: Secretory CO
NEUROHYPOPHYSIS
ºPineal gland
ºmedian eminence of hypothalamus
Tanycytes
specialized ependymal cells that overlie [Circumventricular Organs] and act as barrier between organs & Ventricular CSF
