which of the two smooth muscle layer dilates the pupil
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The iris is composed of two smooth muscle layers, arranged radially and circularly. Which dilates the pupil? The radial smooth muscle layer (dilator pupillae) is responsible for dilating the pupil. Source(s): http://en.wikipedia.org/wiki/Iris_%28ana...http://en.wikipedia.org/wiki/Dilator_pup...LaughingMan · 8 years ago.he iris is composed of two smooth muscle layers, arranged radially and circularly.
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Dilation of the Pupil for Eye Examination One type stimulates contraction of the muscles in the iris that enlarge the pupil and the other type relaxes the muscles that cause pupillary constriction and also relaxes the muscle that allows our eye to focus the lens inside our eye. Some of these eye drops are given together to make the pupil larger. Dilating the eye as a part of an eye examination involves administering medicational eye drops sometimes administered two or three times directly into the eye.
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Iris dilator muscle The iris dilator muscle (pupil dilator muscle, pupillary dilator, radial muscle of iris, radiating fibers), is a smooth muscle of the eye, running radially in the iris and therefore fit as a dilator. The pupillary dilator consists of a spokelike arrangement of modified contractile cells called myoepithelial cells.t is innervated by the sympathetic system, which acts by releasing noradrenaline, which acts on α1-receptors. Thus, when presented with a threatening stimuli that activates the fight-or-flight response, this innervation contracts the muscle and dilates the iris, thus temporarily letting more light reach the retina.
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- The glomeruli of the kidneys contain a smooth muscle like cell called the mesangial cell. Smooth muscle is fundamentally different from skeletal muscle and cardiac muscle in terms of structure and function.unction of smooth muscles depends on the tissues where they are present.... In blood vessels, when the smooth muscles contract, they constrict the lumen of the blood vessels … (arteries) thus increasing the blood pressure, and when they relax, the lumen increases in diameter and thus brings down the blood pressure..
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Pupillary light reflex The pupillary light reflex (PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retinal ganglion cells of the retina in the back of the eye, thereby assisting in adaptation to various levels of lightness/darkness.
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Shared Flashcard Set small bands of smooth muscle cells connect each hair follicle to the papillary layer of the dermis, when these muscles contract, the slanted hair follicle is pulled upright, dimpling the skin surface with goosebumbs
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- The physiology behind a normal pupillary constriction is a balance between the sympathetic and parasympathetic nervous systems. Parasympathetic innervation leads to pupillary constriction. A circular muscle called the sphincter pupillae accomplishes this task. The fibers of the sphincter pupillae encompass the pupil.
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Dissector Answers - Posterior Mediastinum Smooth muscle is present throughout the body, in blood vessels and skin, but is most often considered in the context of thoracic, abdominal, and pelvic viscera. In that it innervates muscle, causing contraction or relaxation, the ANS is similar to the system of skeletal muscle innervation.
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RIXIMKA DUMARKA What are smooth muscles?   Smooth muscle is a type of non-striated muscle, found within the tunica media layer of large and small arteries and veins, the bladder, uterus, male and female reproduct … ive tracts, gastrointestinal tract, respiratory tract, the ciliary muscle, and iris of the eye.2 people found this useful. Smooth muscle is a type of non-striated muscle, found within the tunica media layer of large and small arteries and veins, the bladder, uterus, male and female reproduct … ive tracts, gastrointestinal tract, respiratory tract, the ciliary muscle, and iris of the eye. 2 people found this useful.
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- The ciliary muscle is a ring of smooth fibers that is located in the ciliary body (the structure in the eye that secretes aqueous humor) just behind the iris. Its primary responsibility consists of changing the shape of the eye lens in order to accommodate for distance vision or near vision.
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- The third cranial nerve, the oculomotor nerve, is responsible for pupillary constriction and dilation and for elevation of the upper lid. Along with cranial nerves IV, the trochlear nerve, and VI, the abducens nerve, it also controls eye movements.
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Expert Forum: Eye Dominance The pupil dilates automatically when, for example, there is a ‘fight or flight’ response and when the light is dim. Conversely, within the PSNS, the iris sphincter muscle constricts the pupil. If one were to compare the human eye to a camera lens, the average eye has an ‘f stop’ of f 5.6.
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Tadpole pupil These spasms can affect any segment, or portion, of the iris and involve the iris dilator muscle. Contractions of the iris dilator muscle, a smooth muscle of the eye running radially in the iris, can cause irregular distortion of the pupil, thus making the pupil look tadpole shaped and giving this condition its name. Episodic segmental iris mydriasis was first described and termed “tadpole pupil” in 1912 by HS Thompson
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Ciliary body Relaxation of the ciliary muscle puts tension on these fibers and changes the shape of the lens in order to focus light on the retina. The inner layer is transparent and covers the vitreous body, and is continuous from the neural tissue of the retina.elaxation of the ciliary muscle puts tension on these fibers and changes the shape of the lens in order to focus light on the retina. The inner layer is transparent and covers the vitreous body, and is continuous from the neural tissue of the retina.
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sphincter muscle small, smooth muscle attached to the bulb of the hair which causes erection of the hair and compression of the attending sebaceous gland when it contracts. arterial muscle. part of the tunica media; smooth muscle fibers arranged in a circular pattern around the lumen.
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Introduction to Pupillary Responses Sympathetic innervation leads to pupillary dilation. Dilation is controlled by the dilator pupillae, a group of muscles in the peripheral 2/3 of the iris.
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Glaucoma Before beginning, let's go through the muscles constricting and dilating the pupil. Constriction of the pupil means the pupil (ie the dark hole) becomes smaller. Dilation of the pupil means the pupil becomes larger. The pupil is contricted or dilated by the contraction of smooth muscle in the iris. There are two types.One type is arranged in the circle near the pupil. When a circle of muscle contracts, the circle becomes smaller. Thus contraction of the circular muscle causes constriction of the pupil.onstriction of the pupil means the pupil (ie the dark hole) becomes smaller. Dilation of the pupil means the pupil becomes larger. The pupil is contricted or dilated by the contraction of smooth muscle in the iris. There are two types.
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Pupillary light reflex Under normal conditions, the pupils of both eyes respond identically to a light stimulus, regardless of which eye is being stimulated. Light entering one eye produces a constriction of the pupil of that eye, the direct response, as well as a constriction of the pupil of the unstimulated eye, the consensual response.
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- Smooth muscle, neither striated in structure nor under voluntary control, is found within the walls of organs and structures such as the esophagus, stomach, intestines, bronchi, uterus, urethra, bladder, blood vessels, and the arrector pili in the skin (in which it controls erection of body hair).
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Response of the pupil ? Pupillary reflex. In medicine, there are two pupillary reflexes 1  -. The pupillary light reflex is the reduction of pupil size in response to light. 2  The pupillary accommodation reflex is the reduction of pupil size in response to an object coming close to the eye.
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Pupillary response A dilation response (mydriasis), is the widening the pupil and may be caused by anticholinergic agents or drugs such as MDMA, cocaine and amphetamines. Dilation of the pupil occurs when the smooth cells of the radial muscle, controlled by the sympathetic nervous system (SNS), contract. Constriction of the pupil occurs when the circular muscle, controlled by the parasympathetic nervous system (PSNS), contracts.
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Ciliospinal reflex The ciliospinal reflex (pupillary-skin reflex) consists of dilation of the ipsilateral pupil in response to pain applied to the neck, face, and upper trunk.If the right side of the neck is subjected to a painful stimulus, the right pupil dilates (increases in size 1-2mm from baseline).This reflex is absent in Horner's syndrome and lesions involving the cervical sympathetic fibers.f the right side of the neck is subjected to a painful stimulus, the right pupil dilates (increases in size 1-2mm from baseline). This reflex is absent in Horner's syndrome and lesions involving the cervical sympathetic fibers.
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The iris is composed of two smooth muscle layers, arranged radially and circularly. Which dilates the pupil? The iris is composed of two smooth muscle layers, arranged radially and circularly.he iris is composed of two smooth muscle layers, arranged radially and circularly.
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What muscle controls the size of the pupil? Iris The circular muscles of the iris expand and contract the pupil. The size of the pupil determines how much light will enter the eye, so the iris effectively controls the amount of light that is passed to the retina. The iris is also responsible for eye color (blue, brown, green, hazel). <br /><br />See the related link below for more information on the iris.