Pathology 3500 Lecture Notes - Lecture 34: Intracranial Pressure, Subarachnoid Space, Basement Membrane
1 May 2018
School
Department
Course
Professor
PATH MARCH 16
Uniqueness of the CNS
● Functional localization
● Bony encasement (closed box)
● Increased intracranial pressure
● Herniations
○ When there is increased pressure
○ Brain will move from an area of higher pressure to an area lower pressure
■ Movement is herniation
● Blood brain barrier
○ Tight junction of endothelial cells
○ Basement membrane
○ Astrocyte foot processes forms a web around the blood vessels
Cerebellar Disorder
● Problems in the rate, range, direction and force of movement
○ Rate: can’t consistently tap their hand
○ Range and directly: struggle to hit a target they see
○ Force: can’t consistently tap their hand with the same amount of pressure
Intracranial Pressure and the Closed Box
● The cranium is composed of:
○ The brain
○ The blood
■ Iin artery, veins, capillaries
○ Water
■ CSF in the subarachnoid space, ventricles, lower end of the spinal cord
(spinal cavity)
■ The most “flexible” part of the cranium
● Added pressure causes many problems in the acute setting
○ Small amount of pressure/volume changes can cause issues
■ 45-50 mL of added liquid can cause herniation in young adults
■ Small infants with unfused skulls has more room
○ Edema
○ Hemorrhage
○ Tumor
○ Hydrocephalus
● You can adapt initially by compressing the amount of CSF and venous system
○ Problem arise if the brain needs to shift
● The end result of too much pressure?
○ The brain shifts to equalize pressure
■ Even a slight shift can push it against something hard to bruise it
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Brain will move from an area of higher pressure to an area lower pressure. Astrocyte foot processes forms a web around the blood vessels. Problems in the rate, range, direction and force of movement. Range and directly: struggle to hit a target they see. Force: can"t consistently tap their hand with the same amount of pressure. Csf in the subarachnoid space, ventricles, lower end of the spinal cord (spinal cavity) The most flexible part of the cranium. Added pressure causes many problems in the acute setting. Small amount of pressure/volume changes can cause issues. 45-50 ml of added liquid can cause herniation in young adults. Small infants with unfused skulls has more room. You can adapt initially by compressing the amount of csf and venous system. Problem arise if the brain needs to shift. Even a slight shift can push it against something hard to bruise it.
