Lecture 19 Notes

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Lecture 19 Notes
Atropine blocks cholinergic transmission ( which would normally cause the pupillary constrictor muscles to narrow the diameter of the pupil

Presbyopia – far-sightedness

Retinal Pigment Epithelium(RPE) - contains pigment granules that absorb photons passing through the retina. Also responsible for producing a molecule called a 11-cis retinal.

Hendry’s First Law of Lamination – states that layers exist in the central nervous System where a single structure performs more than one function.

Nuclear Layers – Cell body layers
Plexiform Layers – Synaptic Layers

Retnial Layers
Let’s look at things from the viewpoint of a photon that enters the eye and passes through the dioptic system to enter the vitreous body. From the vitreous body to the retinal pigment epithelium (RPE) light passes through the following layers of the retina: Optic nerve layer - Axons of ganglion cells that will eventually form the optic nerve Ganglion cell layer (GCL) - The cell bodies of ganglion cells Inner plexiform layer - Synaptic layer, where ganglion cell dendrites get inputs from bipolar cells.

Inner nuclear layer - The cell bodies of bipolar cells and of two inhibitory interneurons called horizontal cells and amacrine cells.
Outer plexiform layer - Synapses between bipolar cells, horizontal cells and photoreceptors Outer nuclear layer - Cell bodies of photoreceptors
Inner segments of photoreceptors – Packed full of mitochondria to supply ATP Outer segments of photoreceptors – Site of phototransduction in photoreceptors

Rods contain Rhodopsin
Cones contain Opsin

11-cis Retinal = Chromophore

Photoreceptors are composed of
compartments. Outer segments receive
information, inner segments provide energy
in synthesizing ATP, the axon conducts
messages away from the cell body and to its
terminal and the cell body performs all
protein synthesis. Axon terminals of
photoreceptors tend to be big; those of cones
are so big they are referred...
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