Light enters through the pupil and the size of the pupil is regulated by the iris.Iris has a hole in its center called the pupil. The US president first met with Japanese Prime Minister Fumio Kishida on the eve of the G7 Summit in Hiroshima, emphasizing close US-Japan relations amid China’s growing military and economic.Consists of the colored portion of the eye known as the iris.The choroid coat is the middle layer of the eyeball.Its front surface, the cornea, is transparent to let light enter the eye.Close when objects are placed near the eye: reflex arc Įxternal Structures of the Eye 1.The posterior lining of the eye contains photoreceptors.From 2 outgrowths of the brain that form the optic nerves & the optic cup:.Send information to brain directly via optic nerve.Radial circular Pupil constriction CLICK TO DILATE PUPIL CONSTRICTED In bright light, the circular muscles contract, & the radial muscles relax, pupil constrictsi.e. widens so that much light is able to reach the retina The pupil is the dark space in the centre of the iris The iris contains circular and radial muscles and their activity can change pupil diameter Radial circular CLICK TO CONSTRICT PUPIL DILATED Pupil dilation In dim light, the circular muscles relax& the radial muscles contract, the pupil dilates i.e. Pupil reflex – pupil dilation & constriction light from a near object is focused on the retina – the eye is accommodate i.e.suspensory ligament slackens because the ciliary contracts to a smaller circle taking away the tension out of suspensory ligament.light from a distant object is focused on the retina – the eye is accommodate i.e.suspensory ligament stretched by outward pressure of the humours on the sclera.thickening & thinning of the lens adjusts the focusįocusing: bending of light rays to fall on the retina Light rays from near object Distance Vision Near Vision Light rays form far object.the shape of the lens can be altered by suspensory ligaments and the ciliary muscles.the ability of the eye to alter its focus so that clear images of both close and distant objects can be formed on the retina.lens is elastic & flexible thus it is able to change its shape.the cornea & vitreous humours are mainly responsible for bending of rays of light – refraction while the lens does the final adjustments to focus.an image which is smaller than the object is formed upside-down on the retina.the curved surfaces of the cornea & lens bends the light rays as they pass through them.light from an object forms a focused image on the retina.The retina: contains rods & cones Axon of the ganglion cell direction of light movement Ganglion cell Bipolar cell Synapse Rod Cone Pigment Sclera exit point of the optic nerve cutting through the retina so no rods or cones Blind Spot Optic Nerve carries the impulses from the rods and cones to the visual center of the brain. Fovea a tiny area of densely packed cones for detailed and coloured vision. Cornea bends incoming light focusing it on the retina. Lens accommodation & focusing of light onto the retina. Pupil a hole in the iris that lets light into the back of the eye. Iris controls the pupil size thus controls entry of light. Ciliary Body a ring of muscle controlling the shape and curvature of the lens. ![]() ![]() Retina contains rods and cones which convert light into nerve impulses. Sclera Choroid prevents internal reflection of light and nourish retina. Structure Function(s) tough outer layer of the eye which overs and protect eyeball. Internal Structure of the Eye sclera pupil choroids retina ciliary body / muscles iris lens cornea fovea blind spot optic nerve Visit an eye care unit or clinic with your friends and teacher to observe various charts displaying the anatomy of eye. The is also known as the white of the eye. The is a gel-like substance that helps to keep the eyeball in its proper shape. rods & cones detects light stimuli & converts light energy to nerve impulses which are transmitted to the brain for interpretationĮxternal Structure of the eye Eye lashes Sclera Pupil Iris Eye lid The is the transparent front part of the eye.they contain photoreceptors rods & cones located in the retina.eyes are sense organs that detect and respond to light stimulus giving us sense of sight.the eye allows us to see & interpret the shapes, colors and dimensions of objects in the world by processing the light they reflect.The Eye: Structure & Function The eye contains photoreceptors rods & cones which perceive light stimulus
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