Meninges Flashcards
An epidural hematoma is usually caused by the tearing of a ________ or a ________.
Meningeal artery, venous sinus
A subdural hematoma is usually caused by the tearing of a _______.
Cerebral vein as it penetrates the arachnoid mater
What kind of epithelium covers the choroid plexus?
Simple cuboidal
CSF can either move in ________ between cells or through ________ within the cells to reach the dural sinuses.
Channels, large vacuoles
The brain receives ________ percent of cardiac output and accounts for ________ percent of O2 consumption.
15, 20
What conditions can significantly alter the brain’s metabolism?
General anesthesia
Hypoglycemic coma
Seizures
In the brain, increased PCO2 and decreased PO2 both lead to ________. Increased ________ also leads to this.
Vasodilation and increased flow, H+
In the brain, decreased PCO2 and increased PO2 both lead to ________.
Vasoconstriction and decreased flow
Normal intracranial pressure is ________ mm H20 or ________ mmHg.
65-150, 5-15
An ICP greater than ________ mmHg is considered elevated.
20
At what ICP does cerebral circulation collapse?
90-100 mmHg
What is usually the cause of hydrocephalus?
Blockage of CSF circulation
An uncus herniation projects through the tentorial notch and presses on what structure?
Midbrain
A tonsil herniation projects through the foramen magnum and pressures on what structure?
Medulla
What could cause a cingulate gyrus herniation?
Subdural hematoma
The mean arterial blood pressure (MABP) subtracted from the ICP gives you the ________.
Cerebral perfusion pressure
CPP = MABP - ICP
What are some symptoms of increased ICP?
Headache
Papilledema
Altered mental status
Increased BP
Decreased HR
The ________, a sign of increased ICP, presents with what symptoms?
Cushing reflex (triad)
Increased systolic BP
Increased pulse pressure (pulse pressure is diastolic - systolic)
Decreased HR
If a MABP of 180 is exceeded, loss of ________ of the cerebral blood flow can occur.
Auto-regulation
________ occurs when there is increased permeability of the BBB and increased extracellular fluid. It is usually responsive to ________.
Vasogenic edema, steroids and diuretics
________ occurs when there is hypoxia or failure of the Na/K pump and leads to increased intracellular fluid/cell swelling.
Cytotoxic edema
________ occurs when there is increased edema/fluid in the white matter around the ventricles and is usually associated with hydrocephalus/increased CSF.
Interstitial edema
What are some maneuvers to lower ICP?
Hyperventilate via a respirator
Elevate the head of the bed to 30 degrees
Maintain BP
