Cerebrospinal Fluid, Cerebral Circulation, and Vascular Concepts

Notes

Arachnoid villus Superior sagittal sinus Arachnoid mater Subarachnoid space Dura mater Choroid plexus Third ventricle Cerebral aqueduct Lateralaper ture Fourth ventricle Median aperture Centralcanal of spinal cord Subarachnoid space of spinal cord Figure 14.7 Functions of CSF  Buoyancy  allows brain to attain considerable size without being impaired by its own weight  if it rested heavily on floor of cranium, the pressure would kill the nervous tissue  Protection  protects the brain from striking the cranium when the head is jolted  shaken child syndrome and concussions do occur from severe jolting  Chemical stability  flow of CSF rinses away metabolic wastes from nervous tissue and homeostatically regulates its chemical environment 30 Hydrocephalus • Obstructive Hydrocephalus: • Communicating Hydrocephalus: Intracranial Pressure (ICP) Normal brain pressure: 0-15 mmHg ( by intracranial) Lumbar Pressure: 100-200 mm H20 (by LP) Clinical symptoms appear: 20-25 mmHg Severe ICP: > 40 mmHg Intracranial Pressure (ICP) • Causes of increased ICP: • Intracranial masses • Blockage of CSF • Hemorrhage • Venous sinus thrombosis • Hyperadrenalism • Altitude sickness • Tetracycline Blood ...