L2 - The eye Flashcards
What radiation does light use?
Electromagnetic
What is a photon + what how does it travel?
Particle of light
travels in waves
what’s the speed of light
299,792,458 m/sec
What is amplitude regarding light?
intensity
How is wavelength measured?
the distance between peaks
What is frequency in regards to light?
The no. of waves traveled in a min.
What is the radiation of visible light?
380-760nm emitted by the sun, lightbulbs etc.
What is the vague order for frequency in terms of the colours of visible light?
Follow the rainbow for slowest to fastest frequency e.g., dark red has the slowest frequency and violet has the fastest
Corena
transparent outer coating @ the front of the eye - used for focus
Sclera
white, opaque outer coating
Pupil
the circular hole in the centre of the iris that lets light entre
iris
the pigmented part of the eye that’s visible through the cornea (eye colour)
lens
transparent focusing element of the eye
retina
the photoreceptors and neural circuity that covers the back surface of the eye
fovea
the part of the eye where the centre of an image falls
optic nerve
nerve fibres that carry nerve impulses from the retina to the brain
anterior chamber
between corena + iris
(contains aqueous)
posterior chamber
between iris + lens
(contains aqueous)
how does the lens function?
focuses an image on the retina (accomodation)
lens changes shape to adjust they eye’s focus for stimuli located at different distances
How does the retina fucntion?
lines the back of the eye, detects light in the retinal image + transforms it from light energy t electrochemical energy
(phototransduction)
What are the 2 types of photoreceptors?
rods + cones
What do the rods do?
responsible for vision at low light levels
very sensitive for darkness
Coarse spatial structure
What do cones do?
responsible for vision in bright light + colour vision
used for fine details
How do photoreceptors work?
when light hits a photopigment it splits which activates the photoreceptor cell - the moment of transduction from lightwave to neural impulse.
How do the retinal ganglion cells work?
summarises input from a population of photoreceptor and their axons carry the signal out of the eye and into the brain
What’s a blindspot?
small portion of the visual field of each eye that corresponds to the position of the optic disk (also known as the optic nerve head) within the retina
has no photoreceptors
