Random Flashcards
(41 cards)
What is a tumor from remnant of Rathke’s pouch called?
Craniopharyngioma
What expands to form cerebellum?
Rhombic lip
What separates the thalamus from the hypothalamus?
Hypothalamic sulcus
What is the difference between idiopathic intracranial hypertension and normal pressure hydrocephalus?
Idiopathic intracranial hypertension - no increase in ventricle size, but increase in pressure
Normal pressure - common in elderly, ICP increases only at NIGHT, triad of symptoms: apraxia, incontinence, and dementia (AID)
Which of Rexed’s laminae is only present in cervical/lumbar enlargements?
- At the same place, 8 will be displaced medially and is most anterior
What are areas 5,7 vs S2?
5,7 - for active object manipulation - knows what an object should feel like during a motor task involving eye hand coordination -> knockout = tactile apraxia
SII - lack of stereognosis - unable to feel an object to tell what it is -> memory of tactile sensation.
What is the function of Lisshauer’s tract?
For ALS neurons entering in lateral division, they send collaterals through the posterolateral fasciculus to localize the site of pain to the correct dermatome
What is the function of the CM/PF thalamus for ALS?
Promotes arousal to pain signals
What is the function of the dorsomedial nucleus of the thalamus with regards to ALS?
Links to the limbic system thru reticular formation
What happens with the anterior cingulate cortex is knocked out?
You lose the unpleasant experience of pain. You can still feel it, it’s just unlinked to the limbic system
How do calcium or cAMP modify tyrosine hydroxylase activity?
Ca (via PKC) or cAMP activate a kinase which phosphorylates tyrosine hydroxylase, preventing the the norepinephrine interference of biopterin binding.
What glutamate channel is not open until unblocked by Mg?
NMDA - Not always open
What causes the fast and slow EPSP responses of cholinergic receptors?
Fast: Nicotinic - nonselective ion channels open
Slow: Muscarinic - inhibit the potassium M receptor via GPCR to induce a steady-state depolarization, making the neuron more excitable.
What is the effect of norepinephrine on the hippocampus, and how does this contrast with acetylcholine?
It has a “modulatory effect”, making neurons more excitable WITHOUT modifying membrane potential. This occurs via inhibition of potassium channels involved in repolarization, so the neuron is more excitable in the relative refractory period
What does alpha-bungarotoxin bind?
Nicotinic Ach receptors specifically
What is the mechanism of action for pertussis toxin?
Blocks the muscarinic inhibition of the heart by modifying Gk (hyperpolarizing) and Gi (anti-cAMP, hyperpolarizing).
ADP-ribosylating
What are three mechanisms of Familial Parkinson Disease?
- Defect in Parkin gene -
Adds ubiquitin to proteins - Defect in Alpha-synuclein - causes resistance to degradation of proteins in proteosomes
- Defect in UCH-L1 -
Recycling of ubiquitin from protein fragments
What are the 5 peaks generated on the AEP?
- Generated by CN8
- Generated at cochlear nucleus
- Generated at superior olive / trapezoid body
4/5. Generated in upper pons as impulses travel thru lateral lemniscus / inferior colliculus
What is a Rinne test?
Place the butt of a tuning fork on the mastoid process. Have the patient listen, then put it next to their ear. A normal result is they can hear better when the tuning fork is not touched against them.
Conductive hearing impairment = sounds better when touching bone than when fork is free in air. (Sound is not amplified / transmitted properly by bones).
What is the path of MVST? What is its job?
Ascends from one nuclear complex bilaterally through the medial longitudinal fasciculi (MLF) on both sides. Becomes ipsilateral in caudal medulla, distributes to cervical / upper thoracic segments (T1/T2). Important for head and neck movements of cervical region. Can be found in white matter of anterior funiculus.
What gives input to the fastigial nucleus?
- Vestibular nuclear complex
- Spinocerebellum (anterior lobe vermis)
- Vestibulocerebellum
Where does the vestibular nuclear complex project?
Ipsilaterally to vestibulocerebellum and fastigial nucleus
What are the inputs of the cerebellum back on the vestibular nuclear complex? What is one additional one?
- Vestibulocerebellum - most caudal, ipsilateral input, inhibitory
- Spinocerebellum - most rostral, ipsilateral, inhibitory
- Fastigial nucleus - bilateral, excitatory.
Additionally:
Reticular formation sends fibers to vestibular nuclear complex
What are the minor contributions of the vestibular nuclear complex to efferent control besides eyes and spinal cord?
- Reticular formation (reticulospinal tract)
- Vestibular periphery - excitatory neurons to cristae and maculae
- Thalamus - to VPL, signalling vestibular irritation to the somatosensory cortex eventually (cause of vertigo)