Shit i fogot Flashcards
The brainstem is composed of the midbrain, pons, and medulla, working from superior to inferior respectively.
What is located on the ventral and dorsal side of the midbrain?
Ventral side of midbrain: cerebral peduncles and CN 3
Dorsal side of midbrain: superior and inferior colliculus and CN 4
Location of CN in BS
Midbrain: 3 and 4 Pons: 5 Pontomedullar junction: 6, 7, 8 Medulla: 9, 10, 12 SC: 11
Main feature of ventral medulla is what?
- Pyramids
- olives
CN 10, 11 and 12
CN 3 is located in the midbrain. Where are GSE and GVE located?
GSE: Oculomotor nucleus
GVE: Edinger-westpahl nucleus
. Which of the following is most likely to decrease cerebral blood flow?
a. Hydrocephalus***
b. Acidosis
c. Anemia
d. Very low Pa O2
Hydrocephalus -> increase IP -> obstructs venous flow -> reduced arterial flow to the brain
Acidosis: hydrogen ions associated with acidosis result in ___
vasodilation -> increased cerebral blood flow.
O2 affect on blood flow to the brain
Blood flow is not affects by small changes in O2.
TOO low -> increased.
TOO much -> decreased
A patient with elevated intracranial pressure due to hydrocephalus is evaluated.
Which of the following would be expected to be found in this individual?
a) Severely decreased CSF absorption by the arachnoid villi
b) Increased CSF production rate at the choroid plexus
c) Cerebral blood flow rapidly increases
d) Vasodilation of the cerebral vasculature
D. Vasodilation: decreased cerebral blood flow would limit the availability of oxygen to the
brain.
Vasodilation would occur to increase oxygen delivery.
How does ICP relate with CSF absorption?
High ICP -> High increase in CSF absorption.
This is why when we have hydrocephalus: High ICP -> increase CSF absorption -> obstruct venous outflow -> reduce arterial flow to brain.
Low ICP (less than 68mmHg) -> CSF absorption.
P-glycoprotein does what?
removes toxins that have cross the BBB, back to the blood.
If inhibited (like it is with grape fruit juice) -> result in drugs crossing the BB when they are not permeable to it.
Hypothalamus involvement in nociceptive inputs
Integrates visceral pain with the physiological responses that occur with it
Amygdala involvement in nociceptive inputs
Emotional component of pain
Insular CTX involvement in nociceptive inputs
Interprets the nociceptive information and integrates all signs related to the pain
S1 and S2 involvement in nociceptive inputs
Receive inpiut from nocicpetors and play role in localizing pain
PAG involvement in nociceptive inputs
Descending path that mediates pain.
Slow adapting receptor firing pattern:
fires an
immediate burst of action potentials that persist over multiple seconds and do not
cease their firing rate until the stimulus is completely removed
As part of his surgical pre-admission work-up, Gerald’s CSF is analyzed. Which of the following lab values would be an expected (i.e. normal) finding?
CSF Mg++ levels are higher than plasma Mg++.
CSF glucose levels are higher than those in his plasma.
CSF protein is higher than plasma protein levels.
CSF potassium is the same as that found in his plasma.
CSF Mg++ levels are higher than plasma Mg++.
The higher CSF Mg levels reflect a high need for Mg in the brain (there are lots of NMDA receptors since there is a lot of EAA neurotransmission.
CSF has K+ levels that are lower than in the plasma via the Na/2Cl/K transporter to move K out of the cell. The millions of neurons in the brain mean that extracellular potassium can go high during periods of intense activity (like when you’re reading this…). Since neurons have relatively high permeability to potassium at rest, changes in CSF K could change the excitability of neurons in the brain.
The protection of the cerebral vasculature depends on the __________, which release ____ and ____
Sympathetic NS, which releases NE and NPY.
Vasoconstriction is induced to protect the capillary endothelium (and therefore the blood brain barrier) from damage.
We stretch and tear BV in the brain; what happens
Substance P and Neurokinin A (NKA) are released from nociceptors -> cause vasodilation.
parasympathetic control (ACh) of the cerebrovasculature circulation is _____.
minimal
activation of mu receptors causes:
TRIAD: analgesia, euphoria, respiratory depression
and constipation
2-AG -> endogenous cannabinoid and the receptor is located where and does what?
Located at presynpatic terminal and decrease the release of neurotransmitters at both EAA and GABA-ergic synapses: creates analgesia and euphoria and reduces vomitting.
-Because reduces EAA release-> neuroprotective agent in the brain and reduces excitocitoxicty
CB2 recepptor
Immunological function; triggers removal of B amyloid plaques.
CB2 agonists are being researched for alzheimers
Which of the following would be consistent with a patient being in a minimally conscious state?
Fluent verbal responses to questions that are asked of them.
The ability to raise their hand in response to a command
The ability to focus on a detailed paragraph in a novel.
The absence of sleep/wake cycles
Turning their head towards a sudden noise in the room..
ppl with a MCS
retain the ability to consistently respond to simple commands, such as raise your hand. Although they may occassionally offer spoken responses, they are generally one word answers,
Turning head requires more activation (altertness -> DA)
The important detail to remember is that the cascade that is initiated in response to ischemia in the brain depends on the entrance of _____ into the neurons.
calcium
Obstructions within the subarachnoid space will lead to
Obstructions within the subarachnoid space will lead to communicating forms of hydrocephalus.
