Structure of human eye and its functions pdf

May 27, 2015 structure of human eye and its working. It is present in the form of eyeball in the sockets of our skull. A muscle called the zonula controls both the shape and positioning forward and backwards of the eyes lens. Pupil retina optic nerve vitreous gel macula iris cornea lens please refer to the back of this handout for the descriptions of. It sets three ossicle bones malleus, incus, stapes into motion, changing acoustic energy to mechanical energy. Structure and functions of the human eye the human eyes are the most complicated sense organs in the human body. The structure of the human eye is analogous to that of a camera. Eyes are the most valuable organ of the human body, which process the images of objects in the vicinity.

Structure and function of the eyes msd manual consumer version. A detailed study of the parts of the human eye and their. Structure and function of the eye linkedin slideshare. The eye is also heavily involved with the nervous system, which allows the brain to take in information from the eyes and make the appropriate decisions on how to act upon this information. Structure and function of the eyes eye disorders merck. Synapse with bipolar cells retinal ganglion cells axons form the optic nerve. Figure 364 shows the distribution of the refractive indices in the eye as a function. There are 6 sets of muscles attached to outer surface of eye ball which helps to rotate it in different direction. It has no blood vessels, but its refraction is great. Made of many working parts, the human eye functions much like a digital camera. The sclera provides structure and safety for the inner workings of the eye, but is also flexible so that the eye can move to seek out objects. Fibrous tunic vascular tunic nervous tunic anterior chamber. Its main goal is to transfer the correct image to the optic nerve.

The human eye can differentiate between about 10 million colors and is possibly capable of detecting a single photon. Light enters the eye through the cornea, the clear front surface of the eye, which acts like a camera lens. Its function is to change the shape of lens by contraction or relaxation of muscle. There are several physical and chemical elements that make up the eye. Anatomically, the ear has three distinguishable parts. Besides, these sense organs are pretty much similar to cameras and they help us see objects when light coming from outside enters into. It is amazing that so small can have so many parts.

Half the human cerebral cortex is involved with vision. The spaces within the eye are filled with fluids that help maintain its shape. Creationists suggested that an organ as special as the human eye could not have come about by chance. We have lear nt in the previous chapter about light and some of its. The coating on the interior back of the eye is called the retina. The cornea is the second structure that light strikes. The human eye is an organ which reacts to light and pressure. The human eye has been called the most complex organ in our body.

Dec 12, 2011 the human eye slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. From the muscles and tissues to nerves and blood vessels, every part of the human eye is responsible for a certain action. Cornea is a transparent coat covering the front part of the eye. Eye structure and function to understand how the eye sees, it helps to know the eye structures and functions. How do the lenses used in spectacles correct defects of vision. It is mainly responsible for vision, differentiation of colour the human eye can differentiate approximately 10 12 million colours and maintaining the biological clock of the human body. Its wall has three distinct layersan outer fibrous layer, a middle vascular layer, and an inner nervous layer. This chapter deals with the optical system of the human eye and the correction of its. No doubt, the human eye diagram will add a lot to your knowledge. The domeshaped layer protects human eye from elements against entering in the inner parts of the eye. Lens the lens is a crystalline structure that focuses light into the retina. When light strikes the retina, two types of cells are activated.

Main eye parts and their functions human eyes functions. See well for a lifetime parts of the eye to understand eye problems, it helps to know the different parts that make up the eye and the functions of these parts. Sound waves hit the ear drum, causing it to vibrate like a drum. The human eye is a very sensitive and delicate organ suspended in the eye socket which protects it from injuries. Human eye definition, structure, function, parts, diagram.

It is elastic so that its curvative can be changed to adjust its refractive or fucusing power. The outer, transparent structure at the front of the eye that covers the iris, pupil and anterior chamber. Light enters through the cornea, the transparent outer covering of the eye. The human ear, like that of other mammals, contains sense organs that serve two quite different functions. The movement of these muscles control the size of pupil. Pdf eye structure and physiological functions researchgate. Includes structures that bend light refract converts light energy into action potentials transmitted tobrain. The human eye uses light and enables us to see objects around us. The outer ear consists of the visible portion called the. The sclera is commonly referred to as the whites of the eye.

The eyeball is located in the eye orbit, a round, bony hollow formed by several different bones of the skull. In the orbit, the eye is surrounded by a cushion of fat. It is so central to our way of life that irrational. Structure 1 of human eye introduction how many of your family members use spectacles. Let us study how the human eye uses light and enables us to see objects. Elements of ocular structure 77 the human eye is a simple eye 77 the outermost of the three coats of the eye consists of cornea, limbus, and sclera 78 the middle coatthe uveal tractincludes the iris, ciliary body, and choroid 78 the eyes innermost coatthe retinacommunicates with the brain via the optic nerve 79.

The three types of cones are called red, green, and blue, but each actually detects a range of wavelengths and not these specific colors. The gradient structure of the eye lens helps to avoid reflec. Cornea borders sclera which is a nontransparent eye coat. It helps us in visualizing objects and also helps us in light perception, colour and depth perception. Each eye constantly adjusts the amount of light it lets in, focuses on objects near and far, and produces continuous images that are instantly transmitted to the brain. Pdf eyesight is unquestionably the most important modality of perception that humans possess. But, it cannot give you all the interesting information about its working mechanism and capabilities.

Transmits and refracts light from the front to the back of the eye. The eye is an important and one of the most complex sense organ that we humans are endowed with. Human eye, specialized sense organ in humans that is capable of receiving visual images, which are relayed to the brain. Eyes structure and function the eye transmits visual stimuli to the brain for interpretation and, in doing so, functions as the organ of vision. The anatomy of the eye includes auxillary structures, such as the bony eye socket and extraocular muscles, as well as the structures of the eye itself, such as the lens and the retina. Get a printable copy pdf file of the complete article 934k, or click on a page image below to browse page by page. The human eye facts, functions, structure and problems. It is the clear, transparent front part of the eye that covers the iris, pupil and anterior chamber and provides. This is a smooth, white layer on the outside, but the inside is brown and contains grooves that help the tendons of the eye attach properly. The eye is a hollow, spherical structure measuring about 2. Structure and function of the eyes eye disorders msd. The middle vascular coat choroid, ciliary body, iris. Acoustic energy, in the form of sound waves, passes pinna, ear canal. It is continuous with the choroid and its smooth muscles control the diameter of the pupil.

The adnexal structures, like eyebrows, eyelashes, eyelids, protect eyes from foreign elements and injuries. It is very clear, 98% water, and doesnt change from birth, unlike many fluids in the body that are. Evolution, striving for the structure that will best serve func tion, works through the slow processes of variation and he redity. Sclera the sclera is what is known as the white of the eye.

It is muscular, pigmented and opaque diaphragm which hangs in the eye ball in front of lens. Here are the main eye parts of human eye by which a human can see around himself. The eyes interpret size, shape, colour and distance of the objects and give a 3d picture of the objects visible. The human eye is one of the important sensory organs of the human body. Structure and functions of human eye with labelled diagram. Structure of the eye is essential to understand as it one of the important sensory organs in the human body. It is very sensitive and exposed to various diseases, thus protection and prevention is necessary to keep the eye safe and healthy. If you continue browsing the site, you agree to the use of cookies on this website. Its responsible for focusing light onto the retina. The human eye is an organ that reacts to light and allows vision.

Three layers of human eye the eyeball has three coats as given below. Structure of human eye national council of educational. When you talk of the human eye structure, they exist in pairs, each one being approximately 2. The structures and functions of the eyes are complex. The iris works much like the diaphragm of a cameracontrolling how much light reaches the back of the eye. Anatomy and physiology of the human eye wiley online library. There are many other layers of cornea that provide more protection. Rods detect light and dark and help form images under dim conditions. Human eye anatomy parts of the eye and structure of the.