placode

プラコード

WordNet

1. a small apparently simple structure (as a fertilized egg) from which new tissue can develop into a complete organism
2. an organ in its earliest stage of development; the foundation for subsequent development (同)anlage
3. fish-like vertebrate with bony plates on head and upper body; dominant in seas and rivers during the Devonian; considered the earliest vertebrate with jaws

PrepTutorEJDIC

1. 細菌,ばい菌 / (植物の)胚(はい),幼芽;(動物の)卵子 / 原因;(発達の)初期

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/11/29 16:32:42」(JST)

wiki en

[Wiki en表示]

Neurogenic placodes
Details
Precursor	ectoderm
Gives rise to	cranial ganglia, peripheral nervous system
Identifiers
Latin	placodae neurogenicae
Code	TE E05.15.2.0.0.0.1
Anatomical terminology

A neurogenic placode is an area of thickening of the epithelium in the embryonic head ectoderm layer that gives rise to neurons and other structures of the sensory nervous system.

Placodes are embryonic structures that give rise to structures such as hair follicles, feathers and teeth. The term "neurogenic placode" generally refers to cranial placodes that have neurogenic potential - i.e. those that give rise to neurons associated with the special senses and cranial ganglia. Cranial placodes include a diverse range of structures found across chordates, but the neurogenic placodes found in vertebrates arose later in evolution.

Cranial placodes found in humans

The cranial placodes that have neurogenic potential (i.e. give rise to neurons) can be divided into two groups, the dorsolateral placodes and the epibranchial placodes.

• dorsolateral placodes includes:
  • The trigeminal placode, which consists of ophthalmic and maxillomandibular parts, and gives rise to the cells of the trigeminal ganglion
  • The otic placode forms the otic pit and the otic vesicle, giving rise eventually to organs of hearing and equilibrium.
• The epibranchial or epipharyngeal placodes generate the distal portion of the ganglia of cranial nerves VII, IX and X:
  • The geniculate placode, associated with the first branchial cleft, generates the geniculate ganglion and distal parts of cranial nerve VII
  • The petrosal placode, associated with the second branchial cleft, generates the glossopharyngeal ganglion and distal parts of cranial nerve IX
  • The nodosal placode, associated with the third branchial cleft, generates the nodose ganglion and distal parts of cranial nerve X
• The olfactory placode (or nasal placode) gives rise to the olfactory epithelium of the nose.
• The cranial placodes that do not give rise to neurons are:
  • The lens placode under the direction of the optic vesicle gives rise to the lens of the eye.
  • The adenohypophyseal placode, which forms the anterior lobe of the pituitary gland.

Cranial placodes not found in humans

• The profundal placode, corresponding to the ophthalmic lobe of the trigeminal complex. In Xenopus this remains partly unfused.
• In aquatic vertebrates, the lateral line placodes, which give rise to the lateral line system.
• The hypobranchial placodes, a neurogenic placode found in some amphibians of unknown function

Other ectodermal placodes

The term placode or ectodermal placode is sometimes used to refer specifically to cranial or neurogenic placodes, but is also used for areas of the ectoderm that give rise to structures such as mammary glands, feathers and hair.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 性腺刺激ホルモン（ゴナドトロピン）放出ホルモンの生理学 physiology of gonadotropin releasing hormone
• 2. 低形成腎 renal hypodysplasia
• 3. 神経管欠損症の超音波診断 ultrasound diagnosis of neural tube defects
• 4. 鼻の先天異常 congenital anomalies of the nose
• 5. 潜在性脊椎閉鎖不全症：病因およびタイプ closed spinal dysraphism pathogenesis and types

English Journal

• Sfrp1 and Sfrp2 are not involved in Wnt/β-catenin signal silencing during lens induction but are required for maintenance of Wnt/β-catenin signaling in lens epithelial cells.

• Sugiyama Y, Shelley EJ, Wen L, Stump RJ, Shimono A, Lovicu FJ, McAvoy JW.SourceSave Sight Institute, The University of Sydney, Australia.
• Developmental biology.Dev Biol.2013 Dec 15;384(2):181-93. doi: 10.1016/j.ydbio.2013.10.008. Epub 2013 Oct 16.
• During eye lens development, regulation of Wnt/β-catenin signaling is critical for two major processes: initially it must be silent in the lens placode for lens development to proceed, but subsequently it is required for maintenance of the lens epithelium. It is not known how these different phases
• PMID 24140542

• A time delay gene circuit is required for palp formation in the ascidian embryo.

• Ikeda T, Matsuoka T, Satou Y.SourceDepartment of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
• Development (Cambridge, England).Development.2013 Dec;140(23):4703-8. doi: 10.1242/dev.100339.
• The ascidian larval brain and palps (a putative rudimentary placode) are specified by two transcription factor genes, ZicL and FoxC, respectively. FGF9/16/20 induces ZicL expression soon after the bi-potential ancestral cells divide into the brain and palp precursors at the early gastrula stage. FGF
• PMID 24255097

• Cells or signals: which moves to drive skin pattern formation?

• Headon D.SourceThe Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, EH25 9RG, UK.
• Experimental dermatology.Exp Dermatol.2013 Dec;22(12):795-6. doi: 10.1111/exd.12270.
• During its development, the skin produces an array of evenly spaced hair follicles. How the location of each follicle is determined to produce this pattern has been the subject of study and speculation for several decades. A central unresolved issue is the extent to which movement of scattered, prec
• PMID 24164411

Japanese Journal

• Localization of type III collagen in the lingula mucosa of rats during the morphogenesis of circumvallate papillae

• IWASAKI Shin-ichi,YOSHIZAWA Hideki,AOYAGI Hidekazu
• Odontology : Official journal of the Society of the Nippon Dental University = 歯学 100(1), 10-21, 2012-01-01
• … Immunoreactivity specific for type III collagen was recognized first in the mesenchymal connective tissue just beneath the circumvallate papilla placode in fetuses on E13. … At this stage, most of the lingual epithelium with the exception of the circumvallate papilla placode was pseudostratified epithelium composed of one or two layers of cuboidal cells. … However, the epithelium of the circumvallate papilla placode was composed of several layers of cuboidal cells. …
• NAID 10030282774

• Mutual repression between Pax3 and Pax6 is involved in the positioning of ophthalmic trigeminal placode in avian embryo

• WAKAMATSU Yoshio
• Development, growth & differentiation 53(9), 994-1003, 2011-12-01
• NAID 10030404195

Related Pictures

---

★リンクテーブル★

リンク元	「germ」「プラコード」「原基」「primordium」「anlage」
拡張検索	「nasal placode」

「germ」

　　[★]

• n.

• 微生物、(発生)胚、胚芽、原基

関

anlage、anlagen、embryo、embryonic、germinal、microbe、microbial、microorganism、placode、primordia、primordium

　 　

「プラコード」

　　[★]

英

placode

• 胎児器官の原基を形成する外胚葉の肥厚

• ex. lens placode 水晶体板

• 肥厚板、原基

関

anlage、anlagen、germ、primordia、primordium

「原基」

　　[★]

英

placode, germ, primordium, anlage、primordia、anlagen, rudiment

関

胚、肥厚板、微生物、プラコード、胚芽

「primordium」

　　[★]

• n.

• 原基

redirect 原基

関

anlage、anlagen、germ、placode、primordia

　

「anlage」

　　[★]

原基

関

anlagen、germ、placode、primordia、primordium

「nasal placode」

　　[★] 鼻プラコード

同

olfactory placode