Cerebrospinal fluid CSF; Circulation of CSF
CSF secreted into each ventricle of brain by the choroid plexus.
Choroid plexus are network of capillaries in wall of ventricles.
These ventricle are also covered by ependymal cells which consists of choroid plexus which secrete cerebrospinal fluid.
CSF is secreted mainly in lateral ventricles and it goes from lateral ventricles to third ventricles by a communication called interventricular foramina.
From third ventricle CSF flow into fourth ventricles through communication called cerebral aqueduct.
After reaching fourth ventricle CSF flow through foramina and arachnoid villi into subarachnoid space.
After entering the subarachnoid space, it completely surrounds the brain and spinal cord.
CSF goes from subarachnoid into spinal cord and other hand it goes to brain and excess of CSF goes to the venous sinuses and enter the vascular system.
This system which consist of venous sinuses is one-way valve system.
CSF pressure is higher than venous pressure. This is the reason why extra CSF flows into venous system and it prevents the entry of blood constitutents into brain. Absorption into-
CSF is reabsorbed into blood through arachnoid villi and arachnoid granulation and drain into venous sinuses.
Arachnoid villi permit one-way flow of CSF from subarachnoid space into superior sagittal sinus. Which drain venous blood from brain.
When pressure of fluid in subarachnoid space exceed that of venous blood pressure in superior sagittal sinus, valve open and CSF passes into blood.
When pressure in these two channels is equal or reversed, valve close.
0 Comments