BIO 240 1st Edition Lecture 33 Outline of Last Lecture III Vision a Anatomy of the eye b Photoreceptors c Vision problems Outline of Current Lecture III Vision C Physiology of sight IV Hearing A Physiology of hearing B Reflexes Current Lecture III Vision C Physiology of sight 1 4 lux or higher of light are needed to form an image 2 Light absorption i Retinal A light absorbing molecule that is capable of translating light into electrical signals One of the main components of it is Vitamin A ii Opsin A protein that combines with retinal to form the four pigments of the eye 1 Cones a S cones blue b M cones green c L cones red 2 Rods a Rhodopsin The purple pigment of rods i Accumulates in dim light situations ii Requires very little light to stimulate rods 3 Light adaptation Abruptly going from dark to light Results in a full bleaching of the rods which causes a white blurry glare until the eyes adjust 4 Dark adaptation Abruptly going from light to dark At first the retina can form no images rendering you temporarily blind This is because there isn t a These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute sufficient amount of light to stimulate your rods Rhodopsin starts to quickly build up so that rods can do black and white vision IV Hearing A Physiology of hearing Vestibule External Auditory Meatus Lobe Vestibular Membrane Scala medi Oval Window B Reflexes a Tympanic reflex An adaptation to soften loud noises to protect the inner ear Is subconscious takes a second to occur i Stapedius A skeletal muscle the smallest one in the body and one that is involuntary that attaches to the stapes and when contracted pulls the stapes away from the oval window This dampens sound ii Tensor tympani A muscle that attaches to the malleus and pulls it medially during contraction to tense the tympanic membrane b READING ASSINGMENT ON BLACKBOARD
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