Blue 3 Flashcards
What is writ fly test and what range of stereoacuity does it test
PErformed at 40cm
Tests 3000 to 40 seconds of arc
What stereoacuity may indicate amblyopia
Worse than 250 seconds of arc
What do you need to determine prism power
Refractive indiex
Refracting angle
Where does the fascial sheath attach to the sclera
1.5mm from the corneascleral junction
How wide is sphincter pupillae
1mm wide ring of smoothe muscle
What is the diameter of the eye at the end of the embryonic period
1.5-2mm
Week 8
What cells produce the glycocalyx
Stratified squamous cells of the corneal and conjunctival epithelium
How many photoreceptors interact with one RPE cell
23
How long does regenration of rhodopsin occur after dark adaptation
30 minutex
What happens in Sickle cell
Abdnomral haemoglobin S contains faulty beta chains in haemoglobin molecules
Low oxygen tension promotes sickling
Cell membrane becomes rigid and fragile
How long is PR interval? QR interval
PR 0.12-0.2s
QT 0.35s
What is inspiratory reserve volume
Amount of ait forcible inhaled after normal tidal volume 3000ml
What is tidal volume
Amount of air inhaled during one respiratory cycle
300-500ml
What is residual volume
1200ml
Amount of air left in lungs following full force expiration
What is expiratory reserve volume
1100ml
What substances can directly excite pain receptors? Which cannot?
Bradykinin, serotonin, histamine, acetylcholine, acids, potassium ions, proteolytic enzymes directly excite pain receptors
Prostaglandins and substance P cannot, they enhance sensitivity
Which nephrons have shorter looks of Henle
Corical nephrons have shorter loops of Henle than juxtamedullary
What proportion of nephrons are juxtamedullary
20-30%
What % of tear film is aqueous layer
60%
What arteries does GCA involve?
Cerebral arteries
Ophthalmic arteries
Posterior ciliary branches
Central retinal arteries
Which is worse prognosis epithelioid or spindle cell melanoma
Epithelioid
What are favourable prognostic factors for uveal melanoma
younger patients
Smaller tumours
Chroid location
Spindle cell
Gain in 6p
Worse prognosis for uveal melanoma
Epithelioid
Older patients
Ciliary body
Monosmoy 3
8q additional copies
What causes phayrgoconjunctival fever adenovirus
1, 2, 3, 5, 7, 14
What causes epidemic keratoconjunctivitis
3, 7 ,8 .19
What is lysozyme effective againse
Gram negative organisms and fungi
Ineffective against gram positive
What are SE of beta blockers
Bradycardia
Bronchospasm
Syncope
CNS depression
What do a1 receptors do?
a2 receptors?
b1 receptors
b2 receptors
b3 receptors
a1 - excitatory - SMC contraction
a2 - inhibtiors -
b1 - heart - excitatory
b2 - lungs and vessels - inhibtiory SMC relaxation
What visual field defect can be seen in tilted disc syndrome
Superior bitemporal field defects
Can cross vertical meridian
Filling defect in ICG angiography caused by? Window defect?
Leakage of dye?
Abnormal vessels?
Filing defect - Atrophic ARMD
Window defect - RPE defect, macular hole
Leakage - choroidal neovascularisation
Abnormal blood vessels - choroidal haemangioma
Ultrasound biomicroscopy frequency compared to normal US
Higher frequency transducer
Higher resolution imagin
Less depth penetration
What does patient do in EOG
Intermittently follows targets moving left to right over 30 degree horizontal plane
What is detection bias?
Systematic differences between groups on how outcomes are determined