Circulation in the CNS (CFS + Blood supply) Flashcards
What is the function of CFS fluid?
Nutrition
Bouyancy
Waste removal
Cushioning/protection
Where/what produces the CFS fluid
Choroid plexus that lines the lateral, third & fourth ventricles
Describe the flow of CSF fluid including its reabsorption
Produced in the ventricles by the choroid plexus
Flows through the ventricular system throughout the third, lateral & fourth ventricles
From the fourth ventricle it either exits into the subarachnoid space to surround the cerebrum or continues to flow into the central canal of the spinal cord
CSF in the subarachnoid space is reabsorbed into the circulation (into the superior sagittal sinus) via arachnoid vili (grouped in structures called arachnoid granulations) that project from the subarachnoid space into the superior sagittal sinus
What is the linear connection of the ventricular system
2 lateral ventricles leading to the 3rd ventricle
3rd ventricle connected to the 4th ventricle via the cerebral aqueduct
4th ventricle continuous with the central canal which runs into the spinal cord
What part of the brain is the ventricular system related?
What specific parts of this structure are anatomically associated with each part of the ventricular system?
The cerebrum/cerebral cortex (part of the telencephalon) & brainstem
Each hemisphere/side of the telencephalon has a lateral ventricle
3rd ventricle associated with the thalamus/diencephalon (it is surrounded by it)
Cerebral aqueduct is ventral to the tectum, thus is contained within the midbrain
The 4th ventricle is within the hindbrain (pons & medulla)
- Dorsal to the tegmentum aspect of hindbrain and ventral to the cerebellum
What blood supply is drained by the dural venous sinuses?
Cerebral veins - blood from brain
Diploic veins - spongey bone of skull
Emissery veins - dense connective tissue layer of scalp
What are main dural venous sinuses?
What dural partitions are they associated with?
Superior & inferior sagittal - falx cerebri
Cavernous sinus - diaphragma salle
Straight sinus - tentorium
Transverse sinus - tentorium
Superior petrosal - tentorium
Sigmoid sinus - extension of transverse sinus
What structures run through the cavernous sinus?
Where is it located and where does it drain?
Internal carotid artery
Nerves which lead to the eye through the superior orbital fissure (CN 3, 4, V1, 6)
Two either side of salle turcica and drain ventral part of forebrain
What is the flow of venous blood through the dural sinuses?
The sagittal sinuses, straight sinus (extension of inferior sagittal), cavernous sinuses (via great vein of galen & straight sinus) drain to the CONFLUENCE OF SINUSES
Confluence of sinuses is a dilated space in the internal occipital protuberance
CoS drained by left & right transverse sinuses which become the sigmoid sinus which then empty into the internal jugular vein
