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LIFE SIZE HUMAN HEART MODEL
Discover the beauty of the world through the eyes.
The eye is a spherical body with a diameter of about 23mm, which is the visual organ for people to observe objective things. About 80% of the external information we normally receive comes from vision. The eye is mainly composed of the refractive adjustment system and the visual perception system. The eye is like a fully automatic camera. The refractive system composed of the cornea, pupil, aqueous humor, lens, vitreous and ciliary muscle is equivalent to the lens of the camera, which plays the role of focusing imaging. The retina in the eye and the visual cortex of the brain are equivalent to the photosensitive film of the camera and the computer control system, which can receive external light signals and image. Ronten 6X magnification of the human eye anatomy model, take you to learn more about the eye.
A layer of transparent tissue just in front of the eye. When light enters the eye, it acts as partial focusing. The cornea has five layers of tissue, the outermost being the protective layer of the eye. Behind the cornea is the iris. There is a circular hole in the center of the iris, called the pupil. Its main function is to control the amount of light entering the eyeball (equivalent to the aperture of a camera). When we are in an environment with strong light, the pupil will automatically shrink to reduce the light entering the eyeball and prevent the eye from being burned; when the surrounding light becomes dark, in order to see the object, the pupil will automatically expand to allow more light to enter.
A crystalline object located behind the pupil, which acts as a variable focal length lens. It uses the ciliary muscle to change its shape to adjust the focus, thereby exerting the ability to read at close range. Generally speaking, after the age of 40, the lens will gradually lose its elasticity and become hard, and the phenomenon of presbyopia will occur. At this time, it is necessary to wear reading glasses to help reading.
It is a very fine optic nerve tissue in the inner wall of the eyeball. It is like the film of a camera and has the function of receiving and transmitting images. The retina has the most sensitive visual cells for human visual perception. The retina is divided into three layers, the outermost layer is the photoreceptor cell layer, which is composed of cone and rod cells that receive light stimulation; the middle layer is the bipolar cell layer, which is in the main pathway of information transmission in the retina, which receives light from light. The sensory signal is transmitted to the ganglion cells; the innermost layer is the ganglion cell layer, which is the output neuron of the retina and is responsible for conducting nerve impulses to the visual cortex center of the brain. A large number of cone cells are densely distributed in the foveal area of the retina, which has the sharpest vision.