NEUR 2P36 Lecture Notes - Lecture 7: Bipolar Neuron, Photoreceptor Cell, Opsin
5 Dec 2016
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Concentrated primarily in the center of the retina. Cones: long (reds ~ 700nm) (l-cones, medium (green/yellow ~ 550nm) (m-cones, short ( blue/violet ~400nm) (s-cones) Rare genetic disorder where the retina develops with no cones, only rods. Colour biindness occurs in about 8% of men and about 1% of woman. Deuteranopia: green colour is missing- most common. A photoreceptor absorbs light, transduces it into electrochemical signal that can be used by the neurons. Phototransduction: process where photons are converted into electrical signals. Opsin: is they key molecule for phototransduction: g-protein coupled receptor, different types= different intensities and wavelength. Cgmp stands for cyclic guanosine monophosphate & is active in the darkness. Allows for the release of ts glutamate onto a bipolar neuron. Photo pig(cid:373)e(cid:374)t(cid:859)s a(cid:271)sorptio(cid:374) of light (cid:272)auses the (cid:271)o(cid:374)ds to (cid:271)e altered. Eti(cid:374)al straighte(cid:374)s to (cid:271)e(cid:272)o(cid:373)e (cid:862)all tra(cid:374)s(cid:863) iso(cid:373)er (cid:894)ex. It is no longer able to bind to the opsin.
