How we perceive light

Today in class we talked about the visual system, started off with some anatomy of the eye

As you can see, from anterior to posterior there is the sequential anatomy that follows the pattern. We talked about "blind spots" that exist on the optic disk in the back of our eye where there is not neurons that receives the photo information.

How our eyes receive info is through the process of photo-transduction

there are 5 steps to a photo transduction.

 quote from wikipedia the five steps are "Representation of molecular steps in photoactivation (modified from Leskov et al., 2000). Depicted is an outer membrane disk in a rod. Step 1: Incident photon (hv) is absorbed and activates a rhodopsin by conformational change in the disk membrane to R*. Step 2: Next, R* makes repeated contacts with transducin molecules, catalyzing its activation to G* by the release of bound GDP in exchange for cytoplasmic GTP. The α and γ subunits Step 3: G* binds inhibitory γ subunits of the phosphodiesterase (PDE) activating its α and β subunits. Step 4: Activated PDE hydrolyzes cGMP. Step 5: Guanylyl cyclase (GC) synthesizes cGMP, the second messenger in the phototransduction cascade. Reduced levels of cytosolic cGMP cause cyclic nucleotide gated channels to close preventing further influx of Na+ and Ca2+." 




Also optic cup is developed from the diencephlon of the developing brain.