Eye & Retina Flashcards
What is light?
Visible electromagnetic radiation
What is the canal of Schlemm?
Drains fluid produced from ciliary bodies around the lens
What is the refractive index of air?
1
What is cataracts?
Cloudy lens
What is glaucoma?
Increased eye pressure, reduced blood supply leads to retinal degeneration
What does the iris do?
- Regulates light levels
- Pupillary constrictor
- Pupillary dilator
What kind of muscle aids in the iris during pupillary constriction?
Smooth circular muscle
What kind of muscle aids in the iris during pupillary dilation?
Smooth radial muscle
Cranial nerve III
Occulomotor
Cranial nerve II
Optic nerve
Near response
When you bring an object closer to your eye
What is miosis?
Constriction of the pupils of the eyes
What is special about the retinas in molluscs?
Retina is built right way round so no image flipping
Define scotopic
Vision in low light - low sensitive
Define photopic
Vision in daylight - less light sensitive
Cones or rod scotopic?
Cones
Are rods photopic or scotopic?
Photopic
What is the duplicity theory?
Can’t have high sensitivity and high resolution in a single receptor therefore separate systems for colour and monochrome
Which photopigment is present in rods?
Rhodopsin
Which photopigment is present in cones?
Photopsin
Rods or cones for colour?
Cones
Phototransduction
In physical notes lol cry
What happens to Na+ channels in the photoreceptors that release glutamate in the light? What does this do?
They close thus hyper polarising the receptors, stops inhibiting by glutatmate
When is there no glutamate release?
In the light
When is glutamate released and what does it inhibit?
In the dark and inhibits bipolar cells
“On” bipolar cells
- Hyperpolarised in the dark
- Depolarised by illumination
- Glutamte inhibits via metabotropic glutamate receptors
Conductance increases in light as loss of inhibition by glutamate
“Off” bipolar cells
- Depolarised in dark
- Hyperpolarised by illumination
- Glutamate excites via inotropic glutamate receptors
Conductance decreases in light
Which kind of bipolar cells are hyper polarised in the dark?
ON bipolar cells
Retinal ganglion cell types
- X -mainly cones
- W -mainly from rods
- Y -inputs less defined
- Melanopsin RGCs
Rods and cones are the only type of photoreceptive cells in the retina: true or false?
False, refer to EEG and sleep
What does light cause photoreceptor Na+ channels to do?
Close
