Week 4 Flashcards
What are the 3 types of stroke?
- Ischemic (artery blockage)
- intracerebral haemorrhagic (bleed in brain)
- Subarachnoid haemorrhage (bleed into subarachnoid space)
What is the most common type of stroke?
Ischemic stroke (85% of cases)
What are the symptoms of middle cerebral artery obstruction?
-Neglect
- Apraxia (impaired fine motor functions)
- Anosognosia (not aware they’ve had stroke
- Contralateral arm/leg weakness
What are the symptoms of a anterior cerebral artery stroke?
- Muteness
- Perseveration (get ‘stuck’ on a topic/idea)
- Abulia (lack of motivation to act or think)
- Contralateral arm/leg weakness
What are the symptoms of posterior cerebral artery obstruction?
- Contralateral hemianopia (loss of lateral visual field)
- Memory loss
- Confusion
- Alexia
What are the symptoms of Cerebellar artery obstruction?
Ipsilateral ataxia (clumsiness)
What are lacunar strokes, and what are the symptoms?
Smaller arteries in the brain are obstructed
- Contralateral motor/sensory/both loss
Why are scans need for stroke?
Needed to determine if caused by blockage or bleed as the medications for these two may exacerbate the other if given incorrectly
how can you differentiate between infarcts and bleeds on the CT scans of a stroke patient?
Infarcts take several ours to show up (~8 hrs) and show large dark spots where there has been tissue damage due to lack of blood
Haemorrhages show up immediately as large white patches
how can you tell between a large vessle stroke in the right hemisphere vs the left?
Left
- left gaze preference
- aphasia
Right
- right gaze preference
- neglect
What treatments can be used for stroke?
Thrombolysis (infarcts only)
tPa (blood thinner, for infarcts only)
Surgery (remove clots and clip bleeds)
What are the 3 systems of motor control?
- Corticospinal
- Basal Ganglia
- Cerebellar
What four brain regions are involved with the initiation and activation of muscle movements?
- Primary motor cortex
- Supplementary motor area
- Premotor cortex
- Posterior parietal cortex
What is the role of the primary motor cortex?
To plan and execute movements
What is the role of the supplementary motor cortex?
Plays role in motor planning initiation of movements based on past experience (motor memory)
What is the role of the Premotor cortex?
Regulates posture and is responsive to visual and sensory cues
What is the role of the posterior parietal cortex?
Receives sensory/proprioceptive/visual inputs to determine the position of body parts in space and assess the context in which movements are made
What is responsible for inhibiting the stretch reflex?
Reticulospinal tracts in the spinal cord
What is spacsticity?
A velocity dependant increase in muscle tone
Describe the Direct pathway of the basil ganglia
Striatum inhibits the internal globus palidus, which would normally inhibit the thalamus. Therefore the thalamus sends excitatory signals to the motor cortex
Describe the indirect pathway of the basal ganglia
Striatum inhibits external globus palidus which would normal inhibit the subthalamic nucleus. Therefore the subthalamic nucleus excites the internal globus palidus which inhibits the thalamus. Therefore there is an inhibitory effect on the motor cortex
What are the main neurotransmitters in the basal ganglia pathways?
The cortex uses glutamate to signal the striatum
The rest of the pathways all use GABA
What is the dividing line between the hemispheres of the cerebellum called?
The Vermis
What structure holds the cereblellum to the brainstem?
Peduncles (superior/middle/inferior)
What arteries supply the cerebellum?
Superior cerebellar
Anterior inferior cerebellar
Posterior inferior cerebellar
What are the cerebellar zones and their functions?
Vestibulocerebellum
- Balance and spacial orientation
Spinocerebellum
- Fine tune axial and limb movements
Neocerebellum
- Plan movement and evaluate sensory info
Define a diffuse axon injury
Grey matter and white matter are different densities so when the brain jiggles during trauma axons between these areas can be sheared
Name three excitatory neurotransmitters
- Glutamate
- Aspartate
- Nitric Oxide
Name 4 types of inhibitory
- Glycine
- GABA
- Serotonin
- Dopamine
Name 2 neurotransmitters that are both excitatory and inhibitory
- Acteylcholine
- Norepinephrine
What is the MOA of levadopa?
crosses the blood brain barrier and is converted to dopamine
What drug is usually given with levodopa and why?
Dopa decarboxylase inhibitor, to prevent levodopa being converted to DA n the peripheral nervous system which can cause heart problems
What are the mechanisms of action for Ropinirole and pramipexole?
They are direct dopamine receptor antagonists
What is the MOA of Selegiline?
inhibits MAOb which prevents DA being broken down in the synaptic cleft
What are the 4 components of the blood brain barrier?
- Endothelial cells
- Pericytes
- Astrocytes
- Basement membrane
What is the difference between pharmacokinetics and pharmacodynamics?
Pharmacokinetics = ADME
Pharmacodynamics = MOA, therapeutic effects, and side effects
What are the pharmacokinetics of Levodopa?
A = Facilitate transport in the small intestines
D = Low protein binding allowing transport across BBB
M = Prodrug converted to DA by dopa decarboxylase
E = Rapidly excreted by kidneys
What are the pharmacodynamics of levodopa?
MOA = Levodopa is a prodrug which is converted to DA in the brain
Therapeutic effects = improves symptoms of Parkinson’s
Side effects = Nausea, postural hypertension, dyskinesia
