Case 5: Trapped Brain Flashcards
What is the absolute refractory period?
threshold to repolarisation
What is the relative refractory period?
repolarization to resting
What four things make up the basal ganglia?
substantia nigra
striatum
globus pallidus (internal = inhibitory neuron)
subthalamic nucleus
What is a CT scan good for?
bones
What is an MRI good for and what does it use?
soft tissue
magnetic fields and radio waves
What are the components of the corticospinal tract?
motor cortex
brain stem
spinal cord
skeletal muscle
Motor signals also sent where..?
Basal ganglia (conscious) Cerebellum (unconscious)
Where do the dopamine neurons project into?
striatum
What is the BBB made up of?
endothelial cells
basement membrane
astrocytic end feet
What is involved in the direct pathway?
making movement
cortex excites striatum, striatum inhibits globus PI, GPI no longer inhibits thalamus, thalamus is free to excite the cortex
What is involved in the indirect pathway?
no movement
motor cortex excites the striatum, striatum inhibits GPE, GP can’t inhibit subthalamic nucleus, SN excites GPI which no longer inhibits thalamus, the thalamus is then free to excite the cortex
3 step dopamine creation pathway
tyrosine
L-Dopa
dopamine
What is anosmia?
loss of sense of smell
What do people with PD lose sense of smell?
Lewy bodies in olfactory epithelium
What is a long term consequence of PD treatment?
dyskinesia (dysfunctional movement)
What are 2 disorders of the cerebellum?
intention tremor
cerebellar ataxia
What kind of proteins are present in cases of PD?
Lewy bodies
What are the TRAP symptoms of PD?
tremors
rigidity
akinesia
postural instability
What is bradykinesia?
slow movement
What are 3 movement disorders of the basal ganglia?
akinesia
hypokinesia
bradykinesia
What occurs during deep brain stimulation?
2 electrodes into the globus pallidus
What is madopar?
L-Dopa and benserazide (antagonist)
How is dopamine removed from synapse?
reuptake by dopamine active transporter (presynaptic)
or degraded by COMT or MAO
Where can a high concentration of microglia be found and why?
substantia nigra
dopamine oxidises easily and produces free radicals
