Chapter 11 Flashcards
(17 cards)
retina
innermost layer of the eye
contains neurons that are sensitive to light
anterior chamber
located behind the cornea/ in front of leans contains the aqueous humor
posterior chamber
region between the lens and the iris
when viewing distant objects
the lens is made thin and flat
has least refractive power
when viewing close objects
the lens becomes thick and round
has the most refractive power
5 classes of neurons in the retina
photoreceptors bipolar cells ganglion cells horizontal cells amacrine cells
most direct path of information flow
photoreceptor to bipolar to ganglion cell to optic nerve
horizontal cells
enable lateral interactions between photoreceptors and bipolar cells bc they are maintaining the visual system’s sensitive to contrast over a range of light intensities
pigment epithelium roles
the membrane disks are regenerated every 12 days so they remove the old disks and the regenerate photopigment molecules like retinal once they have been exposed to light
retinoid cycle
the restoration of retinal back to cis conformation in order to be able to react and absorb light
important for maintaining light sensitivity of the photoreceptors
photoreceptors are most sensitive when?
at lower levels of light
two types of ganglion cells
on center and off center
on center cell
will produce a burst of APs when a light is shone into their receptive field
off center cell
will produce a burst of APs when the light is turned off
bipolar cells
have graded potentials which lead to an increase in glutamate release and depolarize On center ganglion cells via AMPA, kianate, and NMDA receptors
off center bipolar cells
have ionotropic receptors AMPA and kianate and cause cells to depolarize in response to glutamate being released
on center bipolar cells
have g protein metabotropic glutamate receptors
when they are bound to glu they will activate the cascade and close the Cgmp Na gated channels reducing the inward current and hyperpolarizing the cell
