PSL300H1 Lecture Notes - Lecture 22: Zonule Of Zinn, Sclera, Far-Sightedness
Document Summary
Anterior chamber: space in front of the lens. Aqueous humor: plasma-like fluid that fills anterior chamber. Vitreous body: the clear jelly that maintains the eyeball"s shape, in vitreous chamber. Cornea: transparent bulge at the front of the eye. Sclera: the whites of the eye outer wall of eyeball. Retina: area at the back of the eye, where light focuses & contains photoreceptors. Iris: the ring of muscle around the opening in the eye. Pupil: the opening allowing light to pass to the lens. Changes size depending on the environment: bright light shrinks, little light enlarges. Can enlarge up to 20-fold: but contributes only little to compensating for brightness, eye operates on a 100-million-fold range of illumination. Controlled by smooth muscles in the iris. Bright light: parasympathetic signals contract the pupillary constrictor muscle. Dark environments: sympathetic signals contract the radial pupillary dilator muscle in the iris dilates pupil.
