1. Meninges, Ventricles, CSF Human Neurobiology ANHB 2217 Avinash Bharadwaj Semester 1, 2006 Week 2

2. Meninges Protective coverings for brain & spinal cord

3. Meninges Dura mater Cranial Spinal Arachnoid mater Pia mater

4. General Features Pia mater – soft, thin, delicate Arachnoid – delicate network Dura – tough, fibrous

5. Other Names! Dura – Pachymeninx – ‘tough’ Arachnoid (like a spider’s web) + Pia – leptomeninges

6. Cranial Dura Mater Bone Endosteal Sinus Meningeal

7. Folds of Dura Falx – the sickle Occupies the longitudinal fissure between cerebral hemispheres Tentorium – the tent Covers the cerebellum The opening accommodates the brainstem

8. Dural Venous Sinuses Veins with dural walls Separation of layers

9. Spinal Dura Not adherent to bone except… Epidural and subdural spaces

10. Ventricles Ependyma Pia The “hollow” brain Diagrammatic Cross Section

11. Pia and Ependyma In some locations pia mater and ependyma come together. A plexus of blood vessels “invaginates” the thin layer. Cerebrospinal fluid enters the ventricle across this membrane.

12. Ventricular System Lateral (1 + 2) 3 4 3rd 4th

13. Cerebrospinal Fluid Choroid plexus Ventricles Openings in the fourth ventricle Subarachnoid Space

14. CSF – Back to Blood Arachnoid Granulations (and villi)

15. Granulations Delicate projections into a sinus One-way flow into the sinus Increased pressure in the sinus blocks the flow Last slide!