01:119:116 Lecture Notes - Lecture 21: Photopsin, Transducin, Opsin
23 Oct 2018
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Document Summary
Very rod shaped (duh: cones provide color vision - less sensitive and therefore contribute very little to our night vision (cone shaped, also duh) Light hits inactive rhodopsin, becomes active -- straightens out, and causes a type of g protein (transducin) to bind to phosphodiesterase, activating phosphodiesterase causes hydrolization of cyclic gmp (bound to sodium. 4/8/14 channel) to unbind from sodium channels, causing sodium channels to close causing cell to hyperpolarize. Basic unit of contraction in skeletal muscle (sarcomeres: adjacent sarcomeres form areas of light and dark bands called striations. Contraction occurs when concentration of ca2+ is high inside muscle cell. Degeneration of motor neurons in spinal cord and brain stem. Causes muscle atrophy - loss of motor ability -- usually fatal b. Autoimmune disease where acetylcholine receptors on muscle fibers are attacked by immune system. Treatment is available; drug inhibit acetylcholinesterase or suppress immunity.
