Week 3 - CSF, Meninges + Ventricular system Flashcards
What is the role of Cerebrospinal fluid? (CSF)
→ Surrounds brain and spinal cord
→ Cushioning + protection
→ Transports nutrients
→ Continually secreted, circulated + absorbed
Where is CSF produced?
→ Mainly in the lateral ventricles in choroid plexus
Where does CSF go after the choroid plexus?
From choroid plexus, it travels to the 3rd ventricle (top of brainstem) to the 4th ventricle.
Once it leaves the 4th ventricle it moves from the ventricular system to the arachnoid space.
It used apertures to achieve this and to disperse CSF around brain and spinal cord./
What does the cerebral aqueduct do?
Connects the 3rd and 4th ventricle
Where else is CSF found?
→ CSF cushions between brain and the skull and provide protection. (e.g. for fast head movements)
→CSF is reabsorbed into the venous system through arachnoid villi, which project principally into the superior sagittal sinus.
→ Superior sagittal sinus drains CSF
→ Central canal of spine
How does CSF travel?
Through the 4 chambers (ventricles) due to foramen/apertures/aqueduct which allow CSF to flow
What is the journey of CSF?
- Produced in the lateral ventricles in the choroid plexus
- Travels through foramen/aqueduct/apertures to the 3rd ventricle
- Travels to 4th ventricle
- Moves from ventricular system to arachnoid space
- CSF dispersed around B + SC
- CSF reabsorbed into venous system through arachnoid villi, which project principally into the superior sagittal sinus
- In SSS, CSF is drained
What are the 3 meninges?
Dura mater
Arachnoid
Pia mater
What is the outer layer called and role?
Dura mater
→ loose, not connected with skull
→ sometimes described as having 2 layers (superior sagittal sinus in between these layers) - drains CSF
What is the middle layer called and role?
Arachnoid
→ underneath sub-dural space
→ beneath arachnoid matter = sub-arachnoid space (CSF is found here)
What is the final layer called and role? (closest to brain)
Pia mater
→ Tightly connected to grooves/sulci of the cortex
State the ventricles of the brain
- Lateral ventricles (2 of these)
- Third ventricle
- Fourth ventricle (connects to 3rd // behind brainstem between cerebellum)
What is the role of veins related to CSF?
Emphasise passage of nutrients + drainage of CSF (absorption/secretion)
What is the superior sagittal sinus and what does it do?
(In dura mater)
→ Unpaired venous structure - originates @ junction of frontal + ethmoid bone
→ Carries waste + fluids away from brain as veins do throughout rest of body
→ Major dural sinuses that receive a considerable amount of venous drainage
What may cause a build-up of CSF in the brain?
→ An increase in production (faulty choroid plexus)
→ Decrease in rate of absorption or from a condition that blocks it’s normal flow through the ventricular system
→ Blocklage of superior sagittal sinus → can cause intracranial hypertension, haemorrhage etc
