Meninges, ventricular system and CSF circulation Flashcards
What are the meninges?
Coverings of the CNS (of connective tissue) which surround the brain and are continuous to spinal cord.
They end at S2.
Meninges are attached to the coccyx by the….
Coccygeal ligament
- Dura mater
- Pia mater
Origin of meninges
Mesoderm and neural crest cells
The ectomeninx will give rise to…
The dura mater
The endomeninx will give rise to…
Pia and arachnoid mater
The middle meningeal artery enters though…
The spinous foramen
Middle meningeal artery causes impressions in the calvaria as it passes between…
Bone and dura mater
The dura mater in the cranium has … layers, in the spinal cord …
2, 1
Name the 2 layers of the cranial dura mater
- Outer periosteal layer
- Inner meningeal layer
The outer periosteal layer is continuous with the …
PERIOSTEUM
The inner meningeal layer forms…
Two-layer reflections, which create septums that separate parts of the brain, like the Falx cerebri.
What does the periosteal layer of the dura mater contain?
Few fibroblasts and blood vessels
The meningeal dura contains…
Abundant collagen layers
Duran border cell layer of the dura mater is also known as …
Plane of structural weakness.
The falx cerebri sits on the…
TENTORIUM
- FALX CEREBRI
- FALX CEREBELLI
What would happen if there is an haemorrhage and there is blood leaking in the plane of structural weakness of the dura mater?
It will disintegrate and the 2 upper layers from the arachnoid beneath and a space which accumulates blood can form between dura and arachnoid: SUBDURAL SPACE.
The tentorium cerebelli inserts in…
Clinoid processes and Petrous part of occipital bone
- Tentorium cerebelli
Tentorium is U shaped so that … can pass trough it.
Brainstem
Diaphragma sellae separates the … from the …
Infundibulum, gland itself.
(Covering the sella turcica)
Innervation of the dura mater
Which nerve accompanies the middle meningeal artery?
Spinosum nerve (mandibular V3)
FALX cerebri anteriorly and posteriorly is innervated by…
V1 ophtalmic nerve. Posteriorly: tentorial nerve
Middle cranial fossa dura mater is innervated by…
V2 and V3
The inferior posterior cranial fossa of dura mater is innervated by…
Branches of C2 and C3
They pass through hypoglossal and jugular foramen.
The straight venous sinus is a continuation of…
The inferior longitudinal sinus
Dural venous sinuses join at…
The confluence of sinuses
Arachnoid consists of two layers:
- central layer: arachnoid barrier cells
- trabecular layer: fibroblasts with spaces between them (SUBARACHNOID SPACE WITH CSF)
Pia mater surrounds… in the subarachnoid space.
Blood vessels
Epidural space: between the…. Contains adipose tissue and venous plexuses. It is a virtual space in the cranium, only appears in … situations
periostium of the vertebral canal and the spinal dura mater
pathological
Subdural space: between the dura mater and arachnoid mater, it is a … space.
Virtual
Subarachnoid space: space between the pia mater and arachnoid mater. Contains…
It makes expansions called…
cerebrospinal fluid (CSF).
Cisterns
IT IS THE ONLY ONE PHYSIOLOGICAL
Epidural and subdural hemorrhages
Subarachnoid hemorrhage
Cerebral cisterns are…
Enlarged regions of subarachnoid space with CSF.
The brain is suspended by the trabeculae of the arachnoid mater and floating within a chamber of CSF. (T/F)
True
The neural tube has a central canal, as the brain expands it forms vesicles which will be converted into…
Ventricles
Within the telencephalon, … ventricles will arise.
Lateral
In the diencephalon, the … ventricle arises.
3rd
…. Connects 3rd and 4th ventricles
Cerebral aqueduct (in mesencephalon)
Within the pons we find the … ventricle
4th
Interventricular foramen (connects lateral ventricles to 3rd ventricle)
The 4th ventricle has … through which fluid passes from the ventricular system to the subarachnoid space.
3 foramina
FORAMINA IN 4TH VENTRICLE
A medial elevation forms, called the medial diverticulum→ site for the …
- 2 lateral diverticulums form and rupture → site for… They form by the end of the 1st trimester of gestation. Through them, the CSF can pass to the subarachnoid space found surrounding the whole brain stem, brain and spinal cord. From the subarachnoid, the fluid will drain mostly into the superior longitudinal sinuses and from there, into general circulation.
Subarachnoid→ Sinuses → Internal Jugular vein (general circulation)
foramen of Magendie (Medial)
foramen of Luschka (Lateral)
CSF content:
CSF > Na+, Cl-, Mg2+ than blood; CSF < K+, Ca2+, Glu & proteins than blood
CSF is secreted by…
choroid epithelial cells of the choroid plexuses
It finally drains into superior longitudinal sinus
Choroid plexuses are found…
Anterior, inferior and posterior area of lateral ventricles. And in the 4th ventricle
How do choroid plexus form?
They are specialisations, the artery penetrates into the boundary of the ventricles, the ependyma (ependymal cells transform into choroid cells)
…control the flow of ions and metabolites into the CSF by selective transport
Choroid cells
Choroid plexuses
We find here an enlarged area filled with a cluster of choroid plexuses called…
GLOMUS CHOROIDEUM
DRAINAGE OF CSF: ARACHNOID VILLI
As said, the fluid then passes to the … through the 3 mentioned foramina, and flows through the subarachnoid space. It’ll be drained through specializations called…, “expansions” of arachnoid mater which pierce the meningeal dura and enter the venous sinuses. In this way, the CSF will be drained as it contacts venous blood. The CSF is being constantly renewed
subarachnoid space
Arachnoid villi
Arachnoid villi leave …
Impressions on the periosteal dura.
If the flow of the CSF is interrupted at any point, there will be accumulation of fluid in the brain and an abnormal dilation of the ventricles. This is known as…
OBSTRUCTIVE HYDROCEPHALUS
Obstructive hydrocephalus happens most commonly in…
CEREBRAL AQUEDUCT
