Week 9 (Test 3) Flashcards
The cerebellum is located infratentorially in the posterior fossa, and is responsible for three main functions:
Maintenance of posture and balance Maintenance of skeletal muscle tone Coordination of voluntary and fine movement
List the tonic systems (geared towards fighting gravity and controlling posture).
Pontine reticulospinal, Vestibulopsinal, and Tectospinal
List the phasic systems (geared towards controlling discrete movements).
Corticospinal, Rubrospinal, and Medullary reticulospinal
- located deep in superior colliculus (which does visual orientation)
- it’s for moving the neck
- helps you track things
tectospinal tract
What is the only solely inhibitory tract?
Medullary Reticulospinal tract
Which tract is found in the genu of the internal capsule?
corticobulbar tract
Lesions to the subthalamic nucleus result in what?
hemiballismus (violent, flinging movment occuring in proximal musculature)
What is the site of origin of climbing fibers in the cerebellum?
inferior olivary nucleus
damage to one side of the cerebellum will result in symptoms on which side?
the ipsilateral side
What are the 3 opioid receptor subtypes?
µ, delta, kappa
Endorphins have the highest affinity for which opioid receptors?
µ
Enkephalins have the highest affinity for which opioid receptors?
delta
Dynorphins have the highest affinity for which opioid receptors?
kappa
What’s the prototype µ-agonist?
Morphine
Used as anesthetic adjuvants
Fentanyl
What are some symptoms of opioid withdrawals?
•Sweating, nausea, vomiting, cramps, shivering, shakes, restlessness
Opioid dependence can be managed with what medications?
methadone or naltrexone treatment.
What is the rate limiting step of alcohol metabolism?
Conversion of ethanol to acetaldehyde by alcohol dehydrogenase the is rate limiting step
reduced effect and reduced concentration in plasma
dispositional tolerance
reduced effect at same concentration in plasma
pharmacodynamic tolerance
What is the Mellanby effect?
Impairment is greater at a given blood alcohol level when BAC is increasing than for the same BAC when the blood alcohol level is falling.
What are the effects of ethanol on the cardiovascular system?
vasodilatation of cutaneous vessels that can lead to hypothermia
What’s the immediate cause of death in methanol poisoning?
Immediate cause of death is respiratory arrest
- Competitive alcohol dehydrogenase inhibitor
- Relatively non-toxic
- Antidote of choice for methanol & ethylene glycol
Fomepizole
What would you give to treat methanol poisoning?
ethanol and Fomepizole
What Treatment would you give for ethylene glycol toxicity?
ethanol and Fomepizole
How do you treat Strychnine Poisoning?
•Treat with IV diazepam, reduced environmental stress, and activated charcoal
What are the effects of coffee on your breathing? Your heart rate?
increases ventilation; slight decrease in heart rate
What are the effects of caffeine on your blood vessels?
- Dilates peripheral vasculature, increasing blood flow to skeletal muscle (particularly during exercise)
- Constricts cerebral vasculature
What is the mechanism of action of caffeine?
Antagonism of adenosine receptors
Caffeine’s half life is increased by what?
- hepatic disease
- pregnant women and women taking oral contraceptives
Caffeine’s half life is decreased by what?
- smoking
- combination with phenytoin or barbiturates
useful pharmacotherapy in smoking cessation
due to blunting of rewarding effects of nicotine
Varenicline
How does Varenicline work?
it is a partial agonist at alph4beta2 nicotinic
receptor subtype
What transmitter does MDMA (ectasy) affect primarily?
serotonin
Bath salts are analogues of ____.
cathinone
•At the site of trauma, while head is still
coup lesion
•At the opposite site of trauma, while head is in motion
contrecoup lesion
Diffuse axonal injury is a result of ____.
angular acceleartion injuries like a rolling car
Epidural hematomas are most commonly caused by ___
Middle meningeal artery tear by fracture
- Bridging vein tear by sudden movement of brain
- Slowly progressive neurologic deterioration
subdural hematoma
What’s the function of the rubrospinal tract?
The fibers terminate on alpha motor neurons and:
- EXCITE flexors of arms
- INHIBIT extensors of arms
What’s the function of the corticorubral fibers?
- These are fibers that come from the cortex and go to the red nucleus
- They inhibit the red nucleus
- This is why your arms aren’t flexed all the time—the corticorubral fibers keep the rubrospinal tract in check!
What are the symptoms of decorticate lesions?
- spastic paralysis (UMN lesion)
- legs extended
- arms flexed
What are the symptoms of a cerebrate lesion?
- spastic paralysis (UMN lesion)
- legs extended
- arms extended
