1. Brain Tidbit I: Nourishment to the brain
Meninges
Ventricles
Cerebro-Spinal Fluid
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

2. What are meninges? (review from spinal cord)
Connective tissues around spinal cord
For protection
For nutrition (CSF)
Three layers
Pia mater
Arachnoid mater
Dura mater
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

3. Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF
Meninges of the Brain
2 dural layers
Endosteal
Meningeal
Form sinuses for blood drainage
Arachnoid, pia mater same as spinal cord
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

4. Structures of the dura mater in skull
Falx cerebri
Falx cerebelli
Tentorium cerebelli
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

5. Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF
Blood supply to brain
Carotid, vertebral aa.
Drain to sinuses formed by dura mater
Blood-brain barrier
Capillary epithelial lining (endothelium) impermeable to water-soluble compounds
Only lipid solubles pass: CO2, O2, sugars, ammonia, small alcohols, lipids like prostaglandins, steroids
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

6. Ventricles (the spaces in your brain…or the USS Enterprise)
2 lateral ventricles in cerebral hemispheres
Third ventricle in diencephaln
Fourth ventricle in pons/cerebellum/
medulla oblongata
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

7. Circulation of Cerebrospinal Fluid
Produced by choroid plexus of ventricles
Passes to sub-arachnoid space of meninges through roof of fourth ventricle
Flows down and around spinal cord
Diffuses freely into nervous tissue
Absorbed out of sub-arachnoid space and into blood at arachnoid villi/granulations in sagittal sinus
500 ml/day, turn-over in 8 hrs
No feedback to choroid plexus—hydrocephalus is consequence of flow or absorption block
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF

8. Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF
CSF Circulation Animation
Human Anatomy and Physiology I, Frolich, Meninges, Ventricles, CSF