The pluriblast is a Pluripotency pluripotent population of Cell biology cells in the early mammal ian conceptus that is distinct from the trophoblast , and gives rise to the germ layer s of the embryo proper , as well as extraembryonic endoderm and extraembryonic mesoderm . Both the pluriblast and trophoblast arise from the Totipotency totipotent cells of the early conceptus. By definition, the pluriblast does not give rise to trophoblast cells during normal development, although it may retain this potential under experimental conditions. In most eutheria n mammals the pluriblast is termed the inner cell mass , as it forms a mass of cells within the fluid filled blastocyst , bounded by the trophoblast. However in metatherian marsupial mammals, and indeed in a small number of eutherian mammals, the pluriblast forms part of the blastocyst wall and no structure exists that can be described as an inner cell mass. Inner cell mass is thus a morphological term peculiar to the majority of eutherian mammals, whereas pluriblast is a functional term more widely applicable to conserved aspects of mammalian development. References Johnson MH and Selwood L 1996 . Nomenclature of early development in mammals. Reproduction, Fertility and Development. 8 759 764. Category Developmental biology ... more details
Italic title Taxobox name Agatha image image caption regnum Animal ia phylum Mollusca classis Gastropoda unranked superfamilia clade Heterobranchia br clade Euthyneura br clade Panpulmonata superfamilia Pyramidelloidea familia Pyramidellidae subfamilia Syrnolinae genus Agatha genus authority Arthur Adams zoologist A. Adams , 1860 ref Adams A. 1860 . Annals and Magazine of Natural History 3 6 422. ref subdivision ranks Species subdivision Agatha virgo small Weisbord, 1962 small Agatha is a small genus of minute sea snail s or marine ocean marine gastropod mollusk s within the subfamily Syrnolinae , which is a part of the family Pyramidellidae . Citation needed date March 2011 They have bilateral symmetry , and only have endoderm and ectoderm tissues. Citation needed date March 2011 The species of this genus are ectoparasites on other invertebrates . Species Agatha virgo Weisbord, 1962 Citation needed date March 2011 References reflist DEFAULTSORT Agatha Gastropod Category Pyramidellidae ... more details
Image Kiemenbogen.jpg thumb Pattern of the branchial arches. I IV branchial arches, 1 4 branchial pouches inside and or pharyngeal grooves outside BR a Tuberculum laterale BR b Tuberculum impar BR c Foramen cecum tongue Foramen cecum BR d Ductus thyreoglossus BR e Sinus cervicalis The branchial apparatus is an embryological structure. ref name urlMedcyclopaedia Branchial apparatus cite web url http www.medcyclopaedia.com library topics volume vi 2 b branchial apparatus.aspx title Medcyclopaedia Branchial apparatus format work accessdate 2009 05 28 ref ref name urlLecture 24. Branchial Apparatus cite web url http www.med.howard.edu anatomy gas wk7 Lecture 2024.htm title Lecture 24. Branchial Apparatus format work accessdate 2009 05 28 ref It consists of branchial groove s from ectoderm branchial arch es from mesoderm pharyngeal pouch es from endoderm branchial membrane s References Reflist Embryology of head and neck Category embryology Category Developmental biology developmental biology stub ... more details
orphan date April 2010 Vegetal Rotation is a Morphogenesis morphogenetic movement that drives mesendoderm internalization during gastrulation in amphibian embryos. ref name winklbauer Winklbauer, R. and Sch rfeld, M., 1999. Vegetal rotation, a new gastrulation movement involved in the internalization of the mesoderm and endoderm in Xenopus . Development 126, 3703 3713. ref The internalization of vegetal cells prior to gastrulation was first observed in the 1930s by Abraham Mandel Schechtman through the use of vital dye labeling experiments in Triturus torosus embryos. ref Schechtman, A.M., 1934. Unipolar ingression in Triturus torosus A hitherto undescribed movement in the pregastrular stages of a urodele. Univ. Calif. Pub. Zool. 39, 303 310. ref More recently, Winklbauer and Sch rfeld 1999 described the internal movements in more detail using pregastrular explants of Xenopus laevis . ref name winklbauer Gastrulation in amphibians is initiated by formation of bottle cells at the dorsal marginal zone, followed by involution of prospective mesodermal cells. ref Gerhart, J., and Keller, R., 1986. Region Specific Cell Activities in Amphibian Gastrulation. Annu. Rev. Cell Biol. 2 201 229. ref The mesoderm and endoderm then migrate animally along the blastocoel roof, driven in part by movement of the vegetal endoderm cells. In Xenopus embryos in which the blastocoel roof is removed prior to gastrulation, the movement of vegetal cells toward the blastocoel and their intercalation into the blastocoel floor causes the floor to spread, pushing the dorsal edge downward. ref name winklbauer In the context of the embryo, active vegetal rotation, together with epiboly of the animal cap ectodermal cells, appears to bring the vegetal mesendoderm into contact with the blastocoel roof. ref name winklbauer ref Papan, C., Boulat, B., Velan, S.S., Fraser, S.E., and Jacobs, R.E., 2007. Formation of the dorsal marginal zone in Xenopus laevis analyzed by time lapse microscopic magnetic res ... more details
A cell type is a distinct morphological or functional form of cell biology cell . When a cell switches state from one cell type to another, it undergoes cellular differentiation . A list of distinct cell types in the adult human body may include several hundred distinct types. ref Molecular Biology of the Cell , Fourth Edition, Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, Peter Walter ref ref http www.copewithcytokines.de cope.cgi?key cell 20types ines.de cope.cgi COPE database ref These are the different cell types in the multicellular organism. Another way to classify cells into types is according to their basic morphology Cell biology Anatomy prokaryotic and eukaryotic . Classification cells into the cell types changes with time, just like the taxonomic classification of organisms. See also Eukaryote Differences among eukaryotic cells overview of different cell types in the multicellular eukaryotes animal, plant, fungal cells Plant cells Cell types plant cell types References Reflist Human cell types derived primarily from ectoderm Human cell types derived primarily from endoderm Germ layer Category Developmental biology cell biology stub de Zelltyp ... more details
distinguish D battery Infobox Anatomy Name PAGENAME Latin endocrinocytus D GraySubject GrayPage Image Control of stomach acid sec.png Caption Control of stomach acid Image2 Caption2 Precursor System Artery Vein Nerve Lymph MeshName D Cells MeshNumber Code Terminologia Histologica TH H3.04.02.0.00027 Delta cells cells or D cells are somatostatin producing cell biology cell s. They can be found in the stomach , intestine and the Islets of Langerhans in the pancreas . In rodents delta cells are located in the periphery of the islets in humans the islet architecture is generally less organized and delta cells are frequently observed inside the islets as well. In the electron microscope , delta cells can be identified as cells with smaller and slightly more compact Granule cell biology granules than beta cell s. D cells contain CCKBR which respond to gastrin and M3 receptors which respond to Ach . Respectively, these receptors will increase somatostatin output and decrease somatostatin output from the D cells. VIP, vasoactive intestinal peptide , acts positively on D cells resulting in more somatostatin being released. Clinical significance A tumor of the delta cells is called a somatostatinoma . Gastrointestinal physiology Human cell types derived primarily from endoderm Category Peptide hormone secreting cells digestive stub cell biology stub gl C lula delta no Deltacelle pl Kom rki D pt C lula delta ru sr ... more details
Unreferenced stub auto yes date December 2009 Invagination means to fold inward or to sheath. In biology , this can refer to a number of processes. Invagination is the morphogenetic processes by which an embryo takes form, and is the initial step of gastrulation , the massive reorganization of the embryo from a simple spherical ball of Cell biology cells , the blastula , into a multi layered organism , with differentiated germ layer s endoderm, mesoderm, and ectoderm. More localized invaginations also occur later in embryonic development, to form coelom, etc. Invagination is the formation of a cleavage furrow during cytokinesis in animal cells. The inner membrane of a mitochondrion invaginates to form cristae, thus providing a much greater surface area to accommodate the protein complexes and other participants that produce ATP. Invagination occurs during endocytosis and exocytosis when a vesicle forms within the cell and the membrane closes around it. Invagination of a part of the intestine into another part is called Intussusception medical disorder intussusception . In the humanities Used to explain a special kind of metanarrative . Used by Rosalind Krauss and Jacques Derrida The Law of Genre , Glyph 7 1980 . In Geology Used to describe a deep depression of strata. Used by Donald L. Baars in The Colorado Plateau Category Cellular processes Category Developmental biology Developmental biology stub es Invaginaci n pt Invagina o ... more details
Infobox Anatomy Name PAGENAME Latin GraySubject GrayPage Image Parathyroid gland high mag cropped.jpg Caption Micrograph of a parathyroid gland . H&E stain . Image2 Caption2 Precursor System Artery Vein Nerve Lymph MeshName MeshNumber Code TerminologiaHistologica 3 08 02.5.00002 Parathyroid chief cells also called parathyroid principal cells or simply parathyroid cells are cell biology cells in the parathyroid gland s which produce parathyroid hormone . The end result of increased secretion by the chief cell s of a parathyroid gland is an increase in the blood plasma serum level of Calcium . Parathyroid chief cells constitute one of the few cell types of the body that regulate intracellular calcium levels as a consequence of extracellular or serum changes in calcium concentration. The calcium sensing receptor CaSR is sensitive to an increase in serum calcium, and stimulates the uptake of calcium by the parathyroid chief cell. This mechanism is critically important, as it describes a physiological feed back loop by which parathyroid hormone secretion is down regulated in response to a restoration of serum calcium. See also Oxyphil cell parathyroid External links BUHistology 15002loa Category Peptide hormone secreting cells Category Human cells Cell biology stub Endocrine system Human cell types derived primarily from endoderm es C lula principal paratiroidea gl C lula principal paratiroidea ja pt C lula principal da paratiroide ... more details
Infobox Anatomy Name PAGENAME Latin GraySubject GrayPage Image Parathyroid gland high mag cropped.jpg Caption Micrograph of a parathyroid gland . H&E stain . Image2 Caption2 Precursor System Artery Vein Nerve Lymph MeshName Oxyphil Cells MeshNumber Code TerminologiaHistologica 3 08 02.5.00005 In the parathyroid gland , the parathyroid oxyphil cell is larger and paler than the parathyroid chief cell . ref BUHistology 15002loa ref These cells can be found in clusters in the center of the section and at the periphery. ref Gartner, p. 208, Fig. 3 ref ref Ross, p. 628, Fig. 1 ref ref DiFiore, pp. 270 271 ref ref Wheater, pp. 312 313 ref Oxyphil cells appear at the onset of puberty, but have no known function. With nuclear medicine scans, they selectively take up the Technetium sestamibi complex radiotracer dye to allow delineation of glandular anatomy. ref Minimally Invasive Radio guided Surgery for Primary Hyperparathyroidism, Annals of Surgical Oncology 12 07 14 12 pp 3401 3402 ref References references Cell biology stub Endocrine system Human cell types derived primarily from endoderm Category Endocrine cells Category Human cells cs Oxyfiln bu ka gl C lula ox fila paratiroidea sl Oksifilna celica ... more details
Infobox Anatomy Name PAGENAME Latin trigonum vesicae urinariae GraySubject 255 GrayPage 1231 Image Illu bladder.jpg Caption Urinary bladder Image2 Gray1140.png Caption2 The interior of bladder. System MeshName MeshNumber DorlandsPre t 19 DorlandsSuf 12823635 The trigone is a smooth triangular region of the internal urinary bladder formed by the two ureteral orifice s and the internal urethral orifice . The area is very sensitive to expansion and once stretched to a certain degree, the urinary bladder signals the brain of its need to empty. The signals become stronger as the bladder continues to fill. Embryologically, the trigone of the bladder is derived from the caudal end of mesonephric ducts , which is of mesoderm mesodermal origin the rest of the bladder is endoderm endodermal . In the female the mesonephric ducts regresses, causing the trigone to be less prominent, but still present. Pathology Clinically important because infection s trigonitis tend to persist in this region. Additional images gallery Image Illu quiz bladder 01.jpg gallery See also Trigonitis External links eMedicineDictionary trigone of bladder SUNYAnatomyLabs 44 04 02 03 The Male Pelvis The Urinary Bladder Urinary system Category Urinary system genitourinary stub de Trigonum vesicae fr Trigone v sical pt Tr gono da bexiga ... more details
Infobox Embryology Name PAGENAME Latin GraySubject 6 GrayPage 50 Image Gray19 with color.png Caption Transverse section of a chick embryo of forty five hours incubation. BR Chordamesoderm yellow, at notochord . BR Paraxial mesoderm red, at somite . BR Intermediate mesoderm purple, near Wolffian duct . BR Lateral plate mesoderm purple, near Somatic mesoderm and Splanchic mesoderm . Image2 Caption2 System CarnegieStage Days Precursor GivesRiseTo mesoderm , notochord MeshName MeshNumber DorlandsPre c 31 DorlandsSuf 12236926 Chordamesoderm , also known as axial mesoderm , is a type of mesoderm that lies along the central axis, under the neural tube . will give rise to notochord starts as the notochordal process, whose formation finishes at day 20. important not only in forming the notochord itself but also in inducing development of the overlying ectoderm into the neural tube will eventually induce the formation of vertebral bodies. ventral floor of the notochordal process fuses with endoderm. The notochord will form the nucleus pulposus of interverterbral discs. There is some discussion as to whether these cells contributed from the notochord are replaced by others from the adjacent mesoderm. It gives rise to the notochordal process which later becomes the notochord External links http instruct1.cit.cornell.edu courses biog105 pages demos 106 unit03 17d.notochorddev.html Diagrams at cornell.edu developmental biology stub Gray s Embryology Category Embryology Category Developmental biology ... more details
Infobox Embryology Name Embryonic disc Latin discus embryonicus GraySubject 6 GrayPage 47 Image Gray11.png Caption Section through embryonic disk of Vespertilio murinus . Image2 Gray13.png Caption2 Surface view of embryo of a rabbit . After K lliker. arg. Embryonic disk. pr. Primitive streak . System CarnegieStage 4 Days Precursor GivesRiseTo MeshName MeshNumber Code Terminologia Embryologica TE E2.0.1.2.0.0.14 The floor of the amniotic cavity is formed by the embryonic disk or embryonic disc composed of a layer of prismatic cells, the embryonic ectoderm , derived from the inner cell mass and lying in apposition with the endoderm . In humans, it is the stage of development that occurs after implantation and prior to the embryonic folding e.g. seen between about day 14 to day 21 post fertilization . It is derived from the epiblast layer, which lies between the hypoblast layer and the amnion . The epiblast layer is derived from the inner cell mass . Through the process of gastrulation , the bilaminar embryonic disc becomes trilaminar. The notochord forms thereafter. Through the process of neurulation , the notochord induces the formation of the neural tube in the embryonic disc. External links MUNAnatomy embryo emb2 http personalpages.manchester.ac.uk staff j.gough lectures the cell diffdev1 page11.html Diagram at manchester.ac.uk Gray s Embryology Category Embryology developmental biology stub fi Alkiolevy ... more details
Infobox Embryology Name PAGENAME Latin epiblastus GraySubject GrayPage Image Gray21.png Caption Section through the embryo. Epiblast visible but not labeled. Image2 Cell differentiation gastrula.PNG Caption2 Cell differentiation System CarnegieStage 3 Days 8 Precursor inner cell mass GivesRiseTo ectoderm , mesoderm , endoderm MeshName MeshNumber Code Terminologia Embryologica TE E5.0.2.2.1.0.1 In amniote animal embryology , the epiblast is a tissue type derived either from the blastodisc in reptiles incl. birds or the inner cell mass in mammal s. It lies above the hypoblast . Mammals In mammalian embryogenesis , the columnar cells of the epiblast are adjacent to the trophoblast , while the cuboidal cells of the hypoblast are closer to the blastocoele . The epiblast, whilst referred to as the primary ectoderm, differentiates to form all three layers of the trilaminar germ disc in a process called gastrulation . Epiblast diversity Human epiblast is disc shaped as opposed to the mouse epiblast which is cup shaped. See also Embryogenesis Mammalian embryogenesis Hypoblast External links http www.embryology.ch allemand iperiodembry carnegie02.html http www.med.umich.edu lrc coursepages M1 embryology embryo 04secondweek.htm http isc.temple.edu marino embryology EMBII97 sld005.htm developmental biology stub Embryology Category Embryology de Epiblast es Epiblasto it Epiblasto pl Epiblast pt Epiblasto ru zh ... more details
Infobox Anatomy Name Enteroendocrine cells Latin endocrinocyti gastroenteropancreatici GraySubject GrayPage Image Digestive hormones.jpg Caption Actions of the major digestive hormones secreted by enteroendocrine cells Image2 Caption2 Precursor System Artery Vein Nerve Lymph MeshName Enteroendocrine cells MeshNumber Code TerminologiaHistologica 3 04 02.0.00024 BR TerminologiaHistologica 3 08 01.0.00003 Enteroendocrine cells are specialized endocrine cell biology cell s of the gastrointestinal tract . They produce hormone s such as serotonin ref UIUCHistologySubject 321 ref , somatostatin , motilin , cholecystokinin , gastric inhibitory peptide , neurotensin , vasoactive intestinal peptide , and enteroglucagon . Most enteroendocrine cells are found in the islets of Langerhans , but they are also found in other locations. For example, the G cell s which secrete gastrin are located primarily in the stomach . ref Medcyclopaedia iv 1 g G cell ref Enteroendocrine cells are also found in the duodenum . ref BUHistology 11604loa Endocrine System duodenum, enteroendocrine cells ref Enterochromaffin like cell and enterochromaffin cells are also considered enteroendocrine cells. ref MeshName Enteroendocrine cells ref Pathology Rare and slow growing carcinoid tumors develop from these cells. When a tumor arises it has the capacity to secrete large volumes of hormones. See also APUD cell References reflist Gastrointestinal physiology Human cell types derived primarily from endoderm Endocrine system anatomy Category Endocrine system Category Cells sl Enteroendokrina celica ... more details
Infobox Anatomy Name PAGENAME Latin cellula centroacinosa GraySubject 251 GrayPage 1204 Image centroacinar cells.jpg Caption Image2 Caption2 System MeshName MeshNumber Code Terminologia Histologica TH H3.04.07.0.00008 Centroacinar cells are spindle shaped cells in the exocrine pancreas . Centroacinar cells are an extension of the intercalated duct cells into each pancreatic acinus . ref name Dr.Wink The intercalated ducts take the bicarbonate to intralobular duct s which become lobular ducts. These lobular ducts finally converge to form the main pancreatic duct. ref name Dr.Wink cite book author Wendy Lackey M.A. title Oral Cavity and Upper GI tract coursepack from Michigan State University College of Human Medicine Lecture session 12 page 327 year 2011 month February pmid doi url issn ref These cells are commonly known as Duct anatomy duct cells , and secrete an aqueous bicarbonate solution under stimulation by the hormone secretin . They also secrete mucin . References reflist External links AnatomyAtlasesMicroscopic 10 213 Pancreas BUHistology 10406loa Liver, Gall Bladder, and Pancreas pancreas, centroacinar cells UIUCHistologySubject 870 USCHistology gi c 108 Gray s cell biology stub Accessory digestive glands Human cell types derived primarily from endoderm Category Digestive system ja ... more details
Infobox Embryology Name PAGENAME Latin blastocystis bilaminaris GraySubject GrayPage Image Gray21.png Caption Section through the embryo. Bilaminar disc is labeled as embryonic disk. Image2 Cell differentiation gastrula.PNG Caption2 Early human gastrula. A. Epiblast B. Bilaminar disc C. Trophoblast D. Hypoblast System CarnegieStage Days 13 Precursor Inner cell mass GivesRiseTo MeshName MeshNumber Code Terminologia Embryologica TE E6.0.1.1.3.0.1 Bilaminar blastocyst or Bilaminar disc refers to the epiblast and the hypoblast , evolved from the embryoblast . ref http staff.um.edu.mt acus1 Gasrtrulation.htm The Third Week Of Life Bot generated title ref ref http isc.temple.edu marino embryology EMBII97 sld002.htm Bilaminar Disc Bot generated title ref These two layers are sandwiched between two balloons the primitive yolk sac and the amniotic cavity. The cells of the inner cell mass which face the blastocyst cavity form a single layer of primitive cells called the hypoblast. The cells at the margin of the hypoblast will begin to multiply and spread with the margins of the hypoblast growing together to create a sac, called the primitive yolk sac later during gastrulation, the hypoblast is replaced by endoderm. Consequently, the hypoblast makes no direct tissue contribution to the fetus. References reflist developmental biology stub Embryology Category Embryology ... more details
Infobox Anatomy Name PAGENAME Latin GraySubject GrayPage Image Caption Image2 Caption2 Precursor System Artery Vein Nerve Lymph MeshName MeshNumber Code TerminologiaHistologica 3 05 02.0.0028 Type I pneumocyte s simple squamous alveolar cells are responsible for gas exchange in the alveoli and cover a majority of the alveolar surface area 95 . While type I pneumocytes account for most of the surface area, they are approximately half as numerous as Type II pneumocyte type II cells , due to differences in size. Type II pneumocytes are large round cells, while type I pneumocytes are smaller cells stretched across a large surface area. Type I pneumocytes are unable to mitosis replicate and are susceptible to toxin toxic insults. In the event of damage, Type II cells can proliferate and or differentiate into type I cells to compensate. cell biology stub respiratory stub Lower respiratory system anatomy Human cell types derived primarily from endoderm Category Lung anatomy Category Human cells ar ja I pt Pneum cito tipo I ... more details
The endocardial heart tubes are paired regions in the embryo that appear in its ventral pole by the middle of the third week of gestation and consist of precursor cells for the development of the embryonic heart . The endocardial heart tubes derive from the Lateral plate mesoderm visceral mesoderm and initially are formed by a confluence of angioblast ic blood vessels on either side of the embryonic midline. The endocardial tubes have an intimate proximity to the foregut or pharyngeal endoderm . ref cite book title Cardiac development last Kirby first Margaret L. authorlink coauthors year 2007 publisher Oxford University Press location isbn 019517819X page 119 pages url http books.google.com books?id fjhCQ QbtbsC accessdate 20 April 2011 ref As folding of the embryo in the horizontal plane initiates in the 4th week of gestation, the endocardial tubes meet in the midline to form the primitive heart tube , which will eventually develop into the histologically definitive endocardium . The myocardium forms from mesoderm cells surrounding the heart tube, while the epicardium develops from other cells, most likely from neural crest cells. References reflist External links EmbryologyTemple Heart98 heart97a sld018 EmbryologyTemple Heart98 heart97a sld019 Development of circulatory system Category Embryology of cardiovascular system Anatomy stub ... more details
cells, called the endoderm , is differentiated and quickly assumes the form of a small sac, called the yolk ... ectoderm , derived from the inner cell mass and lying in apposition with the endoderm. ref name ..., grow downward, and blend with those of the subjacent endoderm . From the sides of the primitive streak a third layer of cells, the mesoderm , extends lateralward between the ectoderm and endoderm the Caudal ... now consists of three layers, named from without inward ectoderm, mesoderm, and endoderm each has ... . The germ layers are referred to as the ectoderm , mesoderm and endoderm . In diploblastic animals only the ectoderm and the endoderm are present ref Campbell . Among different animals, different ... so as to enclose behind them an area that is devoid of mesoderm. Over this area, the ectoderm and endoderm ... is never formed. A third region is at the hind end of the embryo, where the ectoderm and endoderm ... more details
terms of location ventral aspect of the neural groove an axial thickening of the germ layer Endodermendoderm takes place. In bi pedal chordates, e.g. humans, this surface is properly referred to as the anatomical ... shaped cells the notochord which is then separated from the endoderm. citation needed date ... dorsum sell of the sphenoid bone . Initially it exists between the neural tube and the endoderm ... more details
Infobox Embryology Name Genital tubercle Latin tuberculum phallicum tuberculum genitale GraySubject 252 GrayPage 1213 Image Gray1119.png Caption Stages in the development of the external sexual organs in the male and female. Image2 Caption2 System CarnegieStage Precursor somatopleure ref name isbn0 914168 99 1 cite book author Netter, Frank H. Cochard, Larry R. title Netter s Atlas of human embryology publisher Icon Learning Systems location Teterboro, N.J year 2002 isbn 0 914168 99 1 oclc doi page 159 ref GivesRiseTo genital swelling , mons pubis , clitoris , penis MeshName MeshNumber Code Terminologia Embryologica TE E5.7.4.0.1.0.1 A phallic tubercle or genital tubercle is a body of tissue present in the development of the urinary and reproductive organs . It forms in the ventral, caudal region of mammal ian embryo s of both sex es, and eventually develops into a Phallus embryology phallus . In the human fetus the genital tubercle develops around week 4 of gestation , and by week 9 becomes recognizably either a clitoris or penis . This should not be confused with the sinus tubercle which is a proliferation of endoderm induced by paramesonephic ducts. Even after the phallus is developed, the term genital tubercle remains, but only as the terminal end of it, ref name e024 http www.med.unc.edu embryo images unit genital genital htms genital024.htm The University of North Carolina at Chapel Hill Embryo images nr 024 ref which develops into either the glans penis or the glans clitoridis . The genital tubercle is sensitive to dihydrotestosterone and rich in 5 alpha reductase , so that the amount of fetal testosterone present after the second month is a major determinant of phallus size at birth. See also Sexual differentiation References Reflist External links EmbryologySwiss ugenital genitexterne01 http sprojects.mmi.mcgill.ca embryology ug Reproductives Normal Male external.html Overview at mcgill.ca Development of urinary and reproductive systems DEFAULTSORT Genital ... more details
Taxobox name Meristotheca papulosa domain Eukaryota unranked superdivisio Archaeplastida divisio Red algae Rhodophyta classis Rhodophyceae ordo Gigartinales familia Solieriaceae genus Meristotheca species M. papulosa binomial Meristotheca papulosa binomial authority Camille Montagne Montagne J. Agardh Meristotheca papulosa synonyms M. japonica and Eucheuma papulosa is a red alga , popular as a sea vegetable in Taiwan , where it is known as jiguancai zh c p j gu nc i , literally cockscomb vegetable , and in Japan , where it is known as tosaka nori lang ja . Description The plant tissue varies in color from red to peach, the texture is fleshy and cartilaginous, and the shape is flat and leaf like, with irregular deep forking divisions. The edges often grow many branchlets of uneven lengths. The surfaces of older individuals will grow warty or spiky protuberances. The morphology is variable. Length can reach 10 40 cm, with a branch width of 1 5 cm. The interior of the algal body has multiple axes. In the central core, fibrous cells are closely woven together. The endoderm is mostly composed of horn shaped cells. The exoderm is composed of small cells closely packed together. Life cycle It has isomorphic alternation of generations the sporophyte and the gametophyte share a very similar appearance . The tetrasporangia are divided in a ladder shape and scattered across the Cortex botany cortex . The cyst fruits are hemispherical, protrude from the surface, and are scattered across the face and edges. Ecology and distribution It grows on subtidal rocks 5 20 metres deep, and can be seen at all times of the year. It is very widely distributed along the coasts of the Indian Ocean from South Africa to Australia , and the western Pacific Ocean from Australia to Japan . External links cite web url http www.algaebase.org speciesdetail.lasso?species id 2816 work AlgaeBase title Meristotheca papulosa Montagne J. Agardh author M. D. Guiry & Wendy Guiry date 2006 05 10 Cate ... more details
Refimprove date December 2009 Vasculogenesis is the process of blood vessel formation occurring by a de novo production of endothelial cell s. ref name Penn2008 cite book author John S. Penn title Retinal and Choroidal Angiogenesis url http books.google.com books?id Y 26TIIROYwC&pg PA119 accessdate 26 June 2010 date 11 March 2008 publisher Springer isbn 9781402067792 pages 119 ref Process Though similar to angiogenesis , the two are different in one aspect The term angiogenesis denotes the formation of new blood vessels from pre existing ones, whereas vasculogenesis is the term used for the formation of new blood vessels when there are no pre existing ones. ref name urlEndoderm Developmental Biology NCBI Bookshelf cite web url http www.ncbi.nlm.nih.gov bookshelf br.fcgi?book dbio&part A3745 title Endoderm Developmental Biology NCBI Bookshelf format work accessdate 2010 04 07 ref For example, if a monolayer of endothelial cells begins sprouting to form capillary capillaries , angiogenesis is occurring. Vasculogenesis, in contrast, is when endothelial precursor cells angioblasts migrate and differentiate in response to local cues such as growth factors and extracellular matrix to form new blood vessels. These vascular trees are then pruned and extended through angiogenesis. Occurrences for details on vasculogenesis in adults Endothelial progenitor cell Vasculogenesis occurs during embryologic development of the circulatory system . Vasculogenesis can also occur in the adult organism from circulating endothelial progenitor cell s derivatives of stem cells able to contribute, albeit to varying degrees, to neovascularization. Examples of where vasculogenesis can occur in adults are during tumor growth revascularization process following trauma, e.g., after Ischemia cardiac ischemia Endometriosis It appears that that up to 37 of the microvascular endothelium of the ectopic endometrial tissue originates from endothelial progenitor cell s. ref cite doi 10.1093 humupd dmr023 ... more details
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