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 surgical instrument that is used to dilate or distend an opening or an organ (同)dilater
- a drug that causes dilation
- a muscle or nerve that dilates or widens a body part
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』》
- 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）』「2014/01/01 11:01:51」(JST)
[Wiki en表示]
| Iris dilator muscle |
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| 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. (Iris dilator muscle is NOT labeled and not to be confused with "Radiating fibers" labeled near center, which are part of the ciliary muscle.) |
| Latin |
musculus dilatator pupillae |
| Gray's |
subject #225 1013 |
| Origin |
outer margins of iris[1] |
| Insertion |
inner margins of iris[1] |
| Artery |
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| Nerve |
Long ciliary nerves (sympathetics) |
| Actions |
dilates pupil |
| Antagonist |
iris sphincter muscle |
The iris dilator muscle (pupil dilator muscle, pupillary dilator, radial muscle of iris, radiating fibers), is a smooth muscle[2] 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. These cells are stimulated by the sympathetic nervous system.[3] When stimulated by the sympathetic nervous system, the cells contract, widening the pupil and allowing for more light to pass through the eye. Pupillary dilation occurs in two situations: when light intensity changes and when we shift our gaze between distant and nearby objects.[3] The pupillary dilator acts as an antagonist to the pupillary constrictor which narrows the pupil and admits less light to the eye. It has its origin from the anterior epithelium.[4] It is innervated by the sympathetic system, which acts by releasing noradrenaline, which acts on α1-receptors.[5] 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.
The dilator muscle is innervated more specifically by postganglionic sympathetic nerves arising from the superior cervical ganglion as the Sympathetic root of ciliary ganglion. They will follow both short ciliary and long ciliary nerves to reach the dilator muscle.
Contents
- 1 Additional images
- 2 See also
- 3 References
- 4 External links
Additional images[edit]
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Scheme showing sympathetic and parasympathetic innervation of the pupil and sites of lesion in a Horner's syndrome.
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Sympathetic connections of the ciliary and superior cervical ganglia.
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The iris dilator muscle fibers course radially through the iris.
See also[edit]
- Iris sphincter muscle
- Mydriasis
References[edit]
- ^ a b Gest, Thomas R; Burkel, William E. "Anatomy Tables - Eye." Medical Gross Anatomy. 2000. University of Michigan Medical School. 5 Jan. 2010 <http://anatomy.med.umich.edu/nervous_system/eye_tables.html>.
- ^ jneurosci.org Muscarinic and Nicotinic Synaptic Activation of the Developing..
- ^ a b Saladin, Kenneth (2012). Anatomy and Physiology. McGraw-Hill. pp. 616–617.
- ^ "eye, human." Encyclopædia Britannica. Encyclopaedia Britannica Ultimate Reference Suite. Chicago: Encyclopædia Britannica, 2010.
- ^ Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4. Page 163
External links[edit]
- Description of function at tedmontgomery.com
- Slide at mscd.edu
- dilator+pupillae+muscle at eMedicine Dictionary
- BU Histology Learning System: 08010loa
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Sensory system – visual system – globe of eye (TA A15.2.1–6, TH 3.11.08.0-5, GA 10.1005)
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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
- Descemet's
- Endothelium
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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
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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 |
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| Anterior segment |
- Anterior chamber
- Aqueous humour
- Posterior chamber
- Lens
- Capsule of lens
- Zonule of Zinn
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| Posterior segment |
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| Other |
- Asthenopia
- Keratocytes
- Ocular immune system
- Tapetum lucidum
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anat (g/a/p)/phys/devp/prot
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proc, drug (S1A/1E/1F/1L)
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Sensory system: Visual system and eye movement pathways
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| Visual perception |
1° (Bipolar cell of Retina) → 2° (Ganglionic cell) → 3° (Optic nerve → Optic chiasm → Optic tract → LGN of Thalamus) → 4° (Optic radiation → Cuneus and Lingual gyrus of Visual cortex → Blobs → Globs)
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| Muscles of orbit |
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Tracking
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Smooth pursuit: Parietal lobe · Occipital lobe
Saccade: Frontal eye fields
Nystagmus → Fixation reflex → PPRF |
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Horizontal gaze
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PPRF → Abducens nucleus → MLF → Oculomotor nucleus → Medial rectus muscle
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Vertical gaze
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Rostral interstitial nucleus → Oculomotor nucleus, Trochlear nucleus → Muscles of orbit
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Vestibulo-ocular reflex
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Semicircular canal → Vestibulocochlear nerve → Vestibular nuclei → Abducens nucleus → MLF (Vestibulo-oculomotor fibers) → Oculomotor nucleus → Medial rectus muscle
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| Pupillary reflex |
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Pupillary dilation
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1° (Posterior hypothalamus → Ciliospinal center) → 2° (Superior cervical ganglion) → 3° (Sympathetic root of ciliary ganglion → Nasociliary nerve → Long ciliary nerves → Iris dilator muscle)
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Pupillary light reflex
(constriction)
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1° (Retina → Optic nerve → Optic chiasm → Optic tract → Pretectal nucleus) → 2° (Edinger-Westphal nucleus) → 3° (Oculomotor nerve → Parasympathetic root of ciliary ganglion → Ciliary ganglion) → (4° Short ciliary nerves → Iris sphincter muscle)
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Accommodation
vergence
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1° (Retina → Optic nerve → Optic chiasm → Optic tract → Visual cortex → Brodmann area 19 → Pretectal area) → 2° (Edinger-Westphal nucleus) → 3° (Short ciliary nerves → Ciliary ganglion → Ciliary muscle)
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| Circadian rhythm |
Retina → Hypothalamus (Suprachiasmatic nucleus)
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anat (g/a/p)/phys/devp/prot
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proc, drug (S1A/1E/1F/1L)
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UpToDate Contents
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English Journal
- Ultrabiomicroscopic-histopathologic correlations in individuals with autosomal dominant congenital microcoria: three-generation family report.
- Ramirez-Miranda A1, Paulin-Huerta JM, Chavez-Mondragón E, Islas-de la Vega G, Rodriguez-Reyes A.
- Case reports in ophthalmology.Case Rep Ophthalmol.2011 May;2(2):160-5. doi: 10.1159/000328751. Epub 2011 May 13.
- BACKGROUND: Congenital microcoria (CMC) is due to a maldevelopment of the dilator pupillae muscle of the iris, with a pupil diameter of less than 2 mm. It is associated with juvenile open angle glaucoma and myopia. We report on a three-generation Mexican-Mestizo family with CMC. The eldest member's
- PMID 21677884
- Congenital pupillary-iris-lens membrane with goniodysgenesis: histopathologic findings in an enucleated eye.
- Demidenko A1, Jakobiec FA, Hanna E, Walton DS.
- Journal of pediatric ophthalmology and strabismus.J Pediatr Ophthalmol Strabismus.2010 May-Jun;47(3):178-82. doi: 10.3928/01913913-20100505-09. Epub 2010 May 20.
- A 10-year-old boy with clinically confirmed congenital pupillary-iris-lens membrane with goniodysgenesis underwent light microscopic examination of the enucleated eye. The anterior segment changes consisted of the absence of the iridial pupillary sphincter muscle and dilator muscle processes. Endoth
- PMID 20507003
- Mechanical characterization of the bovine iris.
- Heys J1, Barocas VH.
- Journal of biomechanics.J Biomech.1999 Sep;32(9):999-1003.
- Quantification of the mechanical properties of the iris is necessary to assess the clinical significance of passive iris deformation, which has been suggested as a mechanism for certain forms of glaucoma. Extension tests were performed on isolated bovine irises to determine the passive mechanical be
- PMID 10460139
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
- Effects of vasoactive intestinal polypeptide (VIP) and cyclic AMP on isolated dilator pupillae muscle of albino rabbit eye
Related Links
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- dilator pupillae muscle Type: Term Definitions: 1. intrinsic so-called muscle of eyeball; radially disposed layer of muscular processes of the myoepithelial cells that form the epithelium of the posterior surface of the iris, which extends ...
Related Pictures
★リンクテーブル★
[★]
- 英
- dilator pupillae muscle
- ラ
- musculus dilator pupillae
- 関
- 瞳孔括約筋、瞳孔、虹彩、内眼筋。眼
[★]
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