WordNet
- make ones way by force; "He muscled his way into the office"
- animal tissue consisting predominantly of contractile cells (同)muscular_tissue
- one of the contractile organs of the body (同)musculus
- authority or power or force (especially when used in a coercive way); "the senators used their muscle to get the party leader to resign"
- a ring of muscle that contracts to close an opening (同)anatomical sphincter, sphincter_muscle
PrepTutorEJDIC
- 〈U〉(動物体の組織としての)『筋肉』,筋(きん);〈C〉(体の各部を動かす)筋肉 / 〈U〉力,(特に)筋力,腕力 / 《俗に》(…に)強引に割り込む《+『in on』(『into, through』)+『名』》
- 括約筋(かつやくきん)
- 筋肉の,筋力のある / 力ずくの
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2018/01/02 16:26:36」(JST)
[Wiki en表示]
| Iris sphincter muscle |
|
Iris, front view. (Muscle visible but not labeled.)
|
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The upper half of a sagittal section through the front of the eyeball. ("Sphincter of pupil" labeled near bottom-center.)
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| Details |
| Origin |
encircles iris[1] |
| Insertion |
encircles iris[1] |
| Artery |
long posterior ciliary arteries |
| Nerve |
short ciliary nerves |
| Actions |
constricts pupil |
| Antagonist |
iris dilator muscle |
| Identifiers |
| Latin |
Musculus sphincter pupillae |
Dorlands
/Elsevier |
m_22/12550831 |
| TA |
A15.2.03.029 |
| FMA |
49157 |
| Anatomical terms of muscle
[edit on Wikidata]
|
The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil.
Contents
- 1 Comparative Anatomy
- 2 General Structure
- 3 Mode of Action
- 4 Innervation
- 5 See also
- 6 References
- 7 External links
Comparative Anatomy
It is found in vertebrates and some cephalopods.[citation needed]
General Structure
Initially, all the myocytes are of the smooth muscle type but, later in life, most cells are of the striated muscle type.[2]
Its dimensions are about 0.75 mm wide by 0.15 mm thick.[citation needed]
Mode of Action
In humans, it functions to constrict the pupil in bright light (pupillary light reflex) or during accommodation.[citation needed] In lower animals, the muscle cells themselves are photosensitive causing iris action without brain input.[3]
Innervation
It is controlled by parasympathetic fibers of the muscarinic acetylcholine receptor (M3) that originate from the Edinger-Westphal nucleus, travel along the oculomotor nerve (CN III), synapse in the ciliary ganglion, and then enter the eye via the short ciliary nerves.[citation needed]. The short ciliary nerves then run forward and pierce the sclera at the back of the eye, traveling between the sclera and the choroid to innervate the iris sphincter muscle.
See also
References
- ^ a b Gest, Thomas R; Burkel, William E. "Anatomy Tables - Eye." Medical Gross Anatomy. 2000. University of Michigan Medical School. 5 Jan. 2010 <"Archived copy". Archived from the original on 2010-05-26. Retrieved 2010-01-05. >.
- ^ Pilar, G; Nuñez, R; McLennan, I. S.; Meriney, S. D. (1987). "Muscarinic and nicotinic synaptic activation of the developing chicken iris". The Journal of Neuroscience. 7 (12): 3813–26. PMID 2826718.
- ^ "Mouse eyes constrict to light without direct link to the brain". Phys.org (19 June 2017). Retrieved 20 June 2017.
External links
- Overview of function at tedmontgomery.com
- Slide at mscd.edu
- Histology image: 08010loa – Histology Learning System at Boston University
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Anatomy of the globe of the eye
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| Fibrous tunic (outer) |
| Sclera |
- Episcleral layer
- Schlemm's canal
- Trabecular meshwork
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| Cornea |
- Limbus
- layers
- Epithelium
- Bowman's
- Stroma
- Dua's layer
- Descemet's
- Endothelium
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|
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| Uvea/vascular tunic (middle) |
| Choroid |
- Capillary lamina of choroid
- Bruch's membrane
- Sattler's layer
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| Ciliary body |
- Ciliary processes
- Ciliary muscle
- Pars plicata
- Pars plana
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| Iris |
- Stroma
- Pupil
- Iris dilator muscle
- Iris sphincter muscle
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|
| Retina (inner) |
| Layers |
- Inner limiting membrane
- Nerve fiber layer
- Ganglion cell layer
- Inner plexiform layer
- Inner nuclear layer
- Outer plexiform layer
- Outer nuclear layer
- External limiting membrane
- Layer of rods and cones
- Retinal pigment epithelium
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| Cells |
- Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia
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| Other |
- Macula
- Perifoveal area
- Parafoveal area
- Fovea
- Foveal avascular zone
- Foveola
- Optic disc
- Ora serrata
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| Anatomical regions of the eye |
| Anterior segment |
- Adnexa
- Fibrous tunic
- Anterior chamber
- Aqueous humour
- Iris
- Posterior chamber
- Ciliary body
- Lens
- Capsule of lens
- Zonule of Zinn
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| Posterior segment |
- Vitreous chamber
- Retina
- Choroid
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| Other |
- Keratocytes
- Ocular immune system
- Tapetum lucidum
- Eye care professional
- Eye disease
- Refractive error
- Accommodation
- Physiological Optics
- Visual perception
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Optical illusions
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List of optical illusions
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- Afterimage
- Barberpole
- Bezold
- Blivet
- Café wall
- Cornsweet
- Delboeuf
- Ebbinghaus
- Ehrenstein
- Flash lag
- Fraser spiral
- Grid
- Hering
- Jastrow
- Mach
- McCollough
- Müller-Lyer
- Necker
- Orbison
- Penrose
- Peripheral drift
- Poggendorff
- Ponzo
- Rubin
- Sander
- Schroeder
- Ternus
- Vertical–horizontal
- White's
- Wundt
- Zöllner
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|
| Related |
- Auditory
- Tactile
- Temporal
- Op art
- Ascending and Descending
- Waterfall
|
UpToDate Contents
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English Journal
- Pathomechanism of iris sphincter tear.
- Pujari A, Agarwal D, Kumar Behera A, Bhaskaran K, Sharma N.
- Medical hypotheses. 2019 Jan;122()147-149.
- Traumatic iris sphincter tear has been thought to occur secondary to anteroposterior compression of the globe with defined forces lead to equatorial expansion and active pull along the corneoscleral junction and sphincter tear. However, here in this report, we elaborate the additional forces involve
- PMID 30593400
Japanese Journal
- Ultrastructural Changes of the Myoepithelium of the Dilator Pupillae During Miosis and Mydriasis in the Rat Iris.
- Fine Structure, Origin, and Distribution Density of the Autonomic Nerve Endings in the Sphincter and Dilator Muscles of the Pupil of the Mouse
- A DUAL ACTION OF MUSCARINIC PARTIAL AGONISTS ON PUPIL SIZE OF RABBIT
Related Links
- Iris sphincter muscle. Gray878.png · Iris, front view. (Muscle visible but not labeled.) Gray883.png. The upper half of a sagittal section through the front of the eyeball. ("Sphincter of pupil" labeled near bottom-center.) Latin, m. sphincter pupillae ...
Related Pictures
★リンクテーブル★
[★]
- 英
- pupillary sphincter, sphincter pupillae muscle
- ラ
- musculus sphincter pupillae
- 同
- 縮瞳筋
- 関
- 動眼神経、副交感神経、交感神経、瞳孔散大筋、虹彩、対光反射。眼
[★]
括約筋
- 関
- sphincter muscle、sphincteral
[★]