Class 5 Deck 1 Flashcards
what are the 3 main components of the intracranial vault?
- CSF (10-15%)
- Brain (80-85%)
- Blood (5-10%)
CSF occupies the _______ space, providing protective layer of fluid between the ______ and the tissue that surrounds it.
- Subarachnoid
- Brain
Where is the CSF produced?
-The choroid plexus of the ventricles
How much CSF is produced per 24hrs?
500cc
How much CSF volume is present at any given time?
-150cc
How does CSF help brain functioning?
- Regulates PH and Electrolytes
- Carries away waste
- Delivers nutrients
What 4 things can increase CSF volumes?
- Choroid plexus mass
- Hyperthermia
- Decreased serum osmolalilty
- Increased CSF osmolality
What 5 things can decrease CSF volume?
- Hypothermia
- Increased hydrostatic pressure
- Increased serum osmolality
- Decreased CSF osmolality
- Diamox
What arteries provide anterior circulation to the brain?
Carotid
What arteries provide posterior circulation to the brain?Where does it enter?
- Verterbral
- Foramen magnum
Venous blood from the brain drains into the venous sinuses, where do these lie and what do they drain into?
- Lie between the layers of the dura
- Drain into internal jugular
What are the characteristics of the brain venous system?
- Sinuses are valveless
- Blood can move back an forth
- Pressure is negative (embolism)
- No SNS influence
- Chemical influenced
The BBB will allow what type of molecules to pass?
- Small
- Lipophilic
- Passive glucose
- Active AA
The BBB prevents passage of what molecules?
- Large
- Charged (ionized)
BBB is disrupted by what?
- HTN
- Hypoxia
- Trauma/Tumors
- Stroke
- Seizures
- Infection
- ↑ Paco2
Blood flow to the brain is tightly coupled to ______ _____.
-Cerebral metabolism
What 4 things will increase cerebral blood flow?
- Stimulation
- Arousal
- Nocoception
- Hyperthermia
What 2 things decrease CBF?
- Sedative/Hypnotic agents
- Hypothermia
What are the dangerous flow of CBF?
-<15 = Irreversible damage
increased CMRO2 leads to _______ CBF
Increased
How is CPP measured?
-MAP-ICP or CVP (what ever is greater)
What is a normal CPP? ICP?
- CPP = 70-100
- ICP = 10-15
Between what MAP range will the brain autoregulate a constant blood flow?
-60-150
In what 4 ways will brain autoregulation be lost?
- Acidosis
- Hypoxia
- Trauma
- Volatile anesthetics
What 3 ways does the brain compensate for ICP?
- CSF regulation
- CBF auto regulation
- Metabolic autoregulation
How is CSF regulated with an increased ICP?
- ↑ CSF absorption
- ↓ CSF Production