Lecture #9 Flashcards
what makes CSF?
the choroid plexus.
What is cerebral spinal fluid similar to?
plasma, but without other substances.
Where does the choroid plexus make CSF?
in the lateral, third, and fourth ventricles.
What are the functions of CSF?
shock absorption, protection from contusion, communication, medium for circulation of complex molecules, and some data that CSF can create sleep, and cleans out toxins.
What are the three layers of the meninges?
the derma mater which is thick and leathery, the arachnoid layer, which is web-like, harder to see, adherent to dura mater with fibers suspended downward, and the pia mater which is super thin and adheres directly to cortex. There is also the sub-arachnoid space or leptomeninges.
Describe the path of CSF through the ventricles and meninges.
it is created in the lateral, flows to the third ventricle, where more is added, that then flows through the cerebral aqueduct into the fourth ventricle where more is created. It then passes through the 2 lateral and one medial aperture, surrounds the spinal cord, then moves up into the subarachnoid space in the meninges to the top of the brain where it is reabsorbed by villa in the venous sinus.
What is obstructive hydrocephalus?
closure of the cerebral aqueduct through birth defect or tumors of the cerebellum, or blood clots from surgery. CSF builds behind the obstruction. It creates confusion, and rapid neurological decline, and is a medical emergency.
What is normal pressure hydrocephalus (NPH)?
it produces pressure waves instead of normal pressure continuously. It will cause enlargement of the ventricles over months. The flow of CSF gets to the venous sinus, but due to a problem, cannot drain fast enough (example was head trauma in which red blood cells were released into the subarachnoid space that blocked CSF from getting through.
What is the diagnostic triad for NPH?
sudden Dementia (D) urinary incontinence (I) Gait changes (G) walking like a sailor, stride is too wide.
NPH is responsible for what percentage of all dementias?
5%
Describe the process of placing a ventriculoperitoneal shunt.
the head is shaved, scrubbed with betadine, big plastic film is placed so that bacteria from the skin (acid mantle?) keep bacteria from migrating.
A cut is made into the scalp, muscle tissue is pull apart along the brain for better recovery. They expose and drill a quarter-sized hole into the skull, cut the drma mater and pull it back. they stick a tube into cortex and into the ventricle and connect the tube to a reservoir that is disk-shaped. There is a valve between the reservoir and the tube that can be controlled. They tunnel underneath the skin down the head, around the ear, down the neck above the muscle, create an incision at the clavicle, tunneling a hole and down to the peritoneal cavity, which they stab and then insert the tube into. They close up the scalp over the reservoir or valve, which regulates pressure. Can open when the pressure is high and close when it is low. The tube drain extra CSF into the peritoneal cavity.
How is an epidermal hematoma formed?
from skull fracture in which the meningeal artery is torn or compromised. The blood builds up, resulting in brain herniation and death. This is why those with head injuries aren’t left alone for first 24 hours.
Where is a subflaxian herniation?
the dura matter extends down into the longitudinal fissure creating the falx cerebri.
where would you find an uncal herniation? What disorder does it produce?
at the tent or tentorium cerebelli. memory disorder.
What is a subdermal hemotoma?
a bleed below the derma mater but above the brain that can be fixed surgically.
