1 Introduction: the middle of the pupil opening in the iris that is the gateway to the light entering the eye Iris eyes cylindrical coils, the middle of a small hole, which is what we call the pupil, also known as "Irises." It is light at the narrow, in the dark light scattered at large. In the iris, there are two small muscles, called the pupil sphincter, which focus around the pupil, width less than 1mm, which is in charge of narrowing the pupil by the parasympathetic nerve in the dominant; the other big name pupil opening muscle, it is arranged radially in the iris in charge of a large open pupil by sympathetic innervation. The two muscle coordination, mutual constraints, one of a contraction to adapt to different environments. Posed by the multi-unit smooth muscle of iris; in the circular muscle around the pupil is subject to the oculomotor nerve in the parasympathetic innervation, reduced the contraction of the pupil, it is also known as the pupil sphincter; iris is the convergence of peripheral part of the bulk muscle fibers by upstream from the sympathetic innervation of the neck, the contraction of the dilated pupils, it is also known mydriasis muscle. Pupil and the pupil sphincter muscle to open large, the body of the very few come from the neuroectodermal differentiation of muscle. Changes in the scope of the pupil can be very large, when the extreme contraction, the human eye pupil diameter of less than 1mm, while the extreme expansion, it can more than 9mm, the iris sphincter can be reduced to 87% of its length, which is the body other smooth muscle or striated muscle is almost impossible to achieve. Adult pupil diameter is generally 2-4mm, were being round, both sides of the other large, both sides of the difference of not more than 0.25mm, but the difference in pupil diameter as eyes 0.25-0.5mm, pupil reaction and drug experiments showed no abnormality, can be considered as physiological range of pupil In addition to pupil size changes with the intensity of light, but also with age, refractive, physiological status and other factors. Pupillary response points the following kinds: light reaction, dark reaction, adjust the _set_ with the pupil response, eyelid reflex In general, the older the pupil is smaller than the pupil of children to adults, larger, especially in adolescence pupil maximum. Larger than the pupil myopia hyperopia patients. Nervous, excited when the pupil will turn up, take a deep breath, mental and sleep to reduce the pupil. In addition, when there are certain diseases, or the use of certain drugs, the pupil will also open large or small, such as intracranial hematoma, head trauma, encephalitis, gas poisoning, glaucoma, or the use of atropine, a new blessing Lin, epinephrine and other drugs, can make the pupil to open big; pontine hemorrhage, tumors, poisoning, iris and ciliary go far, or the use of pilocarpine, morphine and other drugs, can make the pupil smaller. The pupil before and after the aqueous pathway is, once closed, it will make the eye that barriers to the flow of aqueous humor, resulting in increased intraocular pressure, the formation of secondary glaucoma. Therefore, large or small pupil opening has important clinical significance. Pupil in the light, causing pore size is small, as direct light reflex. Such as light the other eye, the pupil of the eye caused by non-reduced illumination, known as the indirect light reflex. As near objects, due to regulation and vergence occurred miosis, pupillary near reflex is called, the Department of the coordinating role of the cerebral cortex. In PRK and LASIK surgery, the pupil as the center of the cutting to the visual axis as the center than cutting more appropriate, because the symptoms of patients after surgery and dark environment is always more than the cutting zone on the pupil to expand. If the patient's Kappa angle larger as the axis of the cutting should be correspondingly biased. Pupil - the pupil-proliferation Sheep and goats for the horizontal slit-shaped pupil Sympathetic signal muscle contraction can cause pupil dilation, which spread the pupil. Sympathetic nerve damage can lead to unilateral facial miosis (Horner's syndrome). Caused by human interest in seeing the items, or when the pupil will be excited to expand. Psychological studies have found that the pupil is larger than the average human face, especially the woman's face is considered more beautiful. Atropine and other drugs can spread the pupil, depending on the optical refraction in the process used to eliminate the pupil reflex. In addition LSD, cocaine and other drugs can also lead to spread of the pupil. Diffusion is used to determine death of the pupil. Pupil - the pupil of different animals Pupil for the erection of the cat Humans and many animals (except for a few fish) of the pupil by the unconscious control of the size of the iris stretching to regulator into eyes, the light intensity. This is called the pupil reflex. For example, in the bright light of human pupil diameter of about 1.5 mm, in the dim light to expand to 8 mm. Pupil shape of the animal by the optical properties of vitreous, retinal shape and sensitivity, and species of the living environment and to decide. Usually round or slit-like, and some aquatic animals of the pupil is more exotic shapes. Slit-like pupil activity is common in animals under different light intensity. In strong light, these pupils shrunk to the slit, but still allow much of the light fell on the retina. May be slotted in the direction of high sensitivity and animals need to be aware of the direction of movement related. For example, the pupil for the erection of domestic cats, mice and other prey easy to detect lateral movement. Many snakes are slit-like pupil. When in use flash photography, the pupil time to time off, the flash light fundus blood vessel-rich retina, the formation of red-eye phenomenon. With "red-eye reduction" feature is a pre-flash the camera light, so that when the pupil in the official flash has reached contraction. Pupil - miosis Bright eyes met, the iris sphincter (iris sphincter muscle) contraction causes miosis to protect the eyes. This process is dominated by the brain stem. Thus with the loss of pupillary reflex medicine to determine death. People see the object of dislike or hatred, when the pupil to contract. Also morphine, heroin and other drugs can also cause miosis. Iris color change with disease Normal pupil is round, black and transparent, both sides of the other large, about 2.5 mm in diameter, in addition to changes in physiological regulation, but if the pupil diameter of less than 1.5 mm or greater than 5 mm, irregular margins, unusual color, light and slow or disappearance of other, often indicate the occurrence of some diseases. White pupil was found in cataract, iridocyclitis, glaucoma, ocular trauma, high myopia, or systemic diseases such as diabetes. If the pupil found himself white, should go to eye, a detailed medical examination. Hitomi Kong Chengqing Green is common in glaucoma. Has a normal pressure within the eye, glaucoma occurs when the intraocular pressure is too high, you can mist as corneal edema and a series of changes within the eye, so that the issue of a green reflective pupil, the eye will be like as hard rubber, eyes expansion pain torn to shreds. Red pupil in the eye trauma, or some common eye bleeding disorders. According to the number of pupils can be bleeding eyes were different forms, there are varying degrees of visual damage
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Supplementary medical data:
(The following information from the relevant medical books) Thirteen questions: the body's normal pupil is Shiyao like? Thirteen replied: Commonly known as black eye in front of the eye. Black eye surrounded by brown iris is the pupil black hole, the normal pupil is round, 2-5 mm in diameter, bilateral and other large. In case light is miosis, and vice versa dilated pupils.
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Encyclopedia
Pupil pupil Iris center of the hole, the normal diameter of 3 ~ 4mm. Said annular pupil iris sphincter muscle, the muscle contraction, so that miosis; radially arranged smooth muscle within the iris called the pupil to open a large muscle contraction to mydriasis. Can adjust the size of the pupil the amount of light entering the eye.
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English Expression
n.: pupil, pupilla, apple of one's eye, apple of the eye, pupil of the eye