Cognition, Movement and Senses Flashcards
What do these innervate?
a) Alpha motor neurones
b) Gamma motor neurones
a) Skeletal muscle
b) Muscle fibre of muscle spindle
What can be injected in cases of muscle overactivity e.g. dystonia/spascitiy?
Botox (botulinum toxin)
3 months duration, lessens contractions
Definition of:
a) Epilepsy
b) Epileptic seizure
a) tendency to repeatedly have epileptic seizures
2 unprovoked seizures happening >24 hr apart
b) abnormal synchronous firing of a large number of cortical neurons causing symptoms
3 main reasons why epileptic seizures happen
Loss of cortical microcircuit inhibition
Abnormal hyper excitable cortical neuronal firing
Abnormal connections in large-scale brain networks
What are 3 common epilepsy treatments?
Epileptic drugs - act as NT receptors +/ neuronal ion channels
Brain surgery - remove hyper excitable region/sever connections in abnormal large scale network
Neuromodulation - deep brain/vagus nerve stimulation
What are the three reasons signals decay along the axon?
Membrane resistance (Rm) Axial Resistance (Ri) Membrane Capacitance (Cm)
Why are retinal images inverted along both axes?
Light from lateral visual field ==> nasal retina
Light from medial visual field ==> temporal retina
Light from superior ==> inferior parts of retina
Light from inferior ==> superior parts of retina
What part of the eye carries out most of its refraction?
Cornea
How does ciliary muscle and lens change shape depending on object distance?
Far away - ciliary relaxed, lens flat
Close up - ciliary contract, lens thicker + rounder
What is:
a) Emmetropia?
b) Myopia?
c) Hyperopia?
a) Normal vision
b) short- sighted, image focuses in front of retina
c) long-sighted, image focuses behind retina
Where are cones and rods concentrated?
Cones - fovea
Rods - peripheral retina
What is:
a) akinetopsia?
b) prosopagnosia?
a) inability to perceive movements
b) difficulties in face recognition
How are the stereocilia arranged in the ear?
Staircase arrangement with lower steps connected to upper steps with tip links
What ways do the stereocilia have to be bent to open the channels?
Up the stairs - K+ flow into cilia, stretches, open + depolarises
Down the stairs - relax, channel close, re/hyper polarize
What is dysarthria?
Motor speech disorder
Affects movement of speech muscles, X language problem
What condition can accompany dysarthria?
Dysphagia
What is PPA? (speech disorder)
Primary progressive aphasia - slowly + progressive worsens overtime
Results from stroke/brain injury/neurodegenerative e.g. Alzheimer’s
What is cataplaxy?
Sudden loss of muscle tone, usu cos of strong emotion e.g. fear, laughter, anger
Primary vs Secondary headaches
Examples
Primary - x caused by another underlying condition
e.g. migraine, tension, cluster
Secondary - caused by another underlying condition
e.g. trauma, infection
What type of medication are tryptans?
5HT receptors agonists (serotonin receptor agonists)
What are the 7 seizure markers?
- bitten tongue
- confusion following event
- head-turning to 1 side during TLOC
- x memory of abnormal behaviour that was witnessed before, during/after TLOC by someone else
- prodromal déjà vu/jamais vu
- prolonged limb-jerking (brief seizure-like activity can oft occur during uncomplicated faints)
- unusual posturing
What are the classifications of nerve injuries? (3)
Neurapraxia - focal demyelination, axons intact to lesion
Axonotmesis - degeneration of some axons distal to lesion
Neurotmesis - nerve transected - all axons degenerate
When is epilepsy considered to be resolved?
Remained seizure free for last 10 years with x seizure medicines for last 5 years
How can you differentiate between a faint and a seizure depending on how the patient is after the event?
Faint - groggy
Seizure - prolonged period of confusion, drowsiness, irritability, disorientation
What is a reflex seizure?
Occur consistently in response to a particular trigger
What is the first line option for most forms of epilepsy?
What is first line for focal epilepsy?
Sodium valproate - increase GABA activity, relax brain
Carbamazepine
Why is sodium valproate not used in girls and women of childbearing age?
Teratogenic - only use if no other option and strict measures to not get preggers
Which types of seizures can carbamazepine exacerbate?
Myoclonic
Absence
Difference between:
Functional neurological disorder vs factitious disorder vs malingering
Functional - unconsciously mediated
Factitious disorder - consciously feigned for psychological reasons
Malingering - consciously feigned for external gain
What are the three red flag symptoms for cauda equina syndrome?
Bilateral sciatica, saddle anaesthesia, urinary retention
When is a positive Babinski reflex normal?
In baby + infants up to walking age
How long does it take for irreversible neuronal injury to begin during a stroke?
5 minutes after tissue hypoxia
What cells and areas in the brain are most susceptible to hypoxia?
Neocortex
Hippocampus
Purkinje cells (cerebellum)
Watershed areas
What are the watershed areas?
Region between 2 major vessels, least perfused + most susceptible to infection
What is a contraindication for reperfusion therapy in the treatment of stroke?
Intracranial haemhorrhage
Difference between TIA and stroke?
Stroke - rapidly developing symptoms, last >24 hrs, x apparent cause apart from vascular origin
TIA - symptoms lass < 24 hrs
What is a crescendo TIA?
2/more TIAs within a week
Carries high risk of developing ==> stroke.
What are the 4 main points that signify a cerebrovascular event?
Focal
Sudden onset
Negative symptoms - x tingling/arm jerking, more numbness + weakness
Maximum on onset
How do EEGs differ in epileptic seizures and syncope?
Epileptic seizures - spiking of waves
Syncope - flattening/slowing of waves
What type of cells cross BBB, starting the cascade of MS pathogenesis?
T cells
How to test for relative afferent pupil defect?
Pt focuses on distant object in dark room
Shine light in one eye and assess for equal dilation + constriction
Shine light back + forth, pausing for 2 sec
Affected eye - pupil dilates
