|
Visit our new topic page about
coelom
|
coelom
The Columbia Encyclopedia, Sixth Edition | Date: 2008
coelom , fluid-filled body cavity, found in animals, which is lined by cells derived from mesoderm tissue in the embryo , and which provides for free, lubricated motion of the viscera. In animals of the phyla Annelida , Mollusca , and Arthropoda , the mesoderm forms as a mass of tissue from special embryonic cells between an outer layer, the ectoderm , and an inner layer, the endoderm . The coelom then forms as a result of the splitting and hollowing out of the mesodermal mass. In animals of the phyla Echinodermata and Chordata , the mesoderm arises as the lining of folds developing from the endoderm, and the spaces within these folds form the coelom. The structure of the embryonic coelom is relatively simple; in an adult other organs push into the coelomic cavity, and it is also subdivided into compartments, e.g., the pericardial cavity, in which the heart develops. The origin of the coelom is uncertain. The acoelomate theory holds that it evolved from an acoelomate ancestor; the enterocoel that it evolved from gastric pouches of cnidarian ancestors. Recent research, particularly with flatworms and with small worms recently discovered in marine fauna, supports the enterocoel theory.
Author not available, COELOM.,
The Columbia Encyclopedia, Sixth Edition 2008
The Columbia Encyclopedia, Sixth Edition. Copyright 2008 Columbia University Press
Related newspaper, magazine, and journal articles from HighBeam Research
|
Gamete spawning and fertilization in the gymnolaemate bryozoan Membranipora membranacea.
The Biological Bulletin; 10/1/1994; Temkin, M.H.; 5725 words
; ... for oocytes from the maternal visceral coelom to the external seawater. For E. posidoniae ... crustulenta is external to the maternal coelom, occurring while oocytes are in either ... Membranipora membranacea is within the maternal coelom, whereas the site of egg activation is ...
Read more
|
|
|
Changes in larval morphology in the evolution of benthic development by Patiriella exigua (Asteroidea: Asterinidae), a comparison with the larvae of Patiriella species with planktonic development.
The Biological Bulletin; 6/1/1995; Byrne, M.; 6329 words
; ... ILLUSTRATION FOR FIGURE 3A OMITTED]. A single coelom forms at the anterior end of the archenteron ... ILLUSTRATION FOR FIGURE 3B OMITTED]. This coelom subsequently forms the lumen of the central ... externally in 3-day-old larvae, the anterior coelom has branched into the two lateral arms ...
Read more
|
|
|
Waveform dynamics of spermatozeugmata during the transfer from paternal to maternal individuals of Membranipora membranacea.
The Biological Bulletin; 2/1/2004; Temkin, M.H. Bortolami, S.B.; 6584 words
; ... membranacea migrate into the perivisceral coelom from the peritoneum of the body wall ... membranacea are motile in the paternal coelom, like sperm of other gymnolaemate bryozoans ... become positioned in the perivisceral coelom between the body wall and the distomedial ...
Read more
|
|
Evaluation of coelioscopic splenic biopsy and cloacoscopic bursa of fabricius biopsy techniques in pigeons (Columba livia).(Original Studies)
Journal of Avian Medicine and Surgery; 12/1/2006; Hernandez-Divers, Stephen J. Wilson, G. Heather Lester, Vanessa K. Hernandez-Divers, Sonia M. Latimer, Kenneth S. Ritchie, Branson W.; 3239 words
; ... anesthesia by a left lateral approach to the coelom from behind the last rib. From within ... respiratory tract, gastrointestinal tract, and coelomic viscera, particularly the urogenital tract ... all patients. The image quality of the coelomic viscera was excellent, and all structures ...
Read more
|
|
PROGRAM OF THE 44TH ANNUAL MEETING.
Bulletin of the New Jersey Academy of Science; 3/22/1999; 21103 words
; ... ADDUCTOR MUSCLE, PERICARDIAL GLAND, PERICARDIAL COELOM, AND VENTRICLE OF THE HARD SHELL CLAM, MERCENARIA ... present either in the pericardial gland or pericardial coelom. The pericardial coelom contains concretions of various sizes, consistencies ...
Read more
|
|
|
Madreporite function and fluid volume relationships in sea urchins.
The Biological Bulletin; 12/1/1996; Ferguson, John C.; 5107 words
; ... medium, as well as from the perivisceral coelomic fluid (PCF) which is variably 1.5 mosmol ... water vascular system to the perivisceral coelom, thus maintaining the fluid volume of ... canal of asteroids into the perivisceral coelomic space were probably the main route of ...
Read more
|
|
|
Morphogenesis and organogenesis in the regenerating planktotrophic larvae of asteroids and echinoids.
The Biological Bulletin; 10/1/2002; Vickery, Minako S. Vickery, Michael C.L. McClintock, James B.; 6819 words
; ... digestive system and a pair of non-connected coelomic pouches (Fig. 1B). Mid-stage larvae were ... region. Internally, the left and right coelomic pouches were connected at the anterior ... brachiolar apparatus possessed an underlying coelom. Latestage larvae were defined as either ...
Read more
|
|
Evidence for sequential hermaphroditism in Sabellastarte spectabilis (polychaeta: sabellidae) in Hawai'i (1).
Pacific Science; 10/1/2006; Bybee, David R. Bailey-Brock, Julie H. Tamaru, Clyde S.; 3101 words
; ... sampled had only one type of gamete in the coelom, but both eggs and sperm were seen in the coelom of 15% of individuals, demonstrating the ... were classified as unknown. Fresh samples of coelomic contents were also extracted from live worms ...
Read more
|
|
|
The structure and mode of function of the water vascular system of a brittlestar, Ophioderma appressum.
The Biological Bulletin; 2/1/1995; Ferguson, John C.; 5132 words
; ... a unique arrangement of fluid-filled coelomic passages and associated parts. The general ... long thin boundary with the perivisceral coelomic extension that partially encases the interradial ... it is separated from the perivisceral coelom by a thin layer of connective tissue ...
Read more
|
|
|
Spermiogenesis and modified sperm morphology in the "seepworm" Methanoaricia dendrobranchiata (polychaeta: orbiniidae) from a methane seep environment in the Gulf of Mexico: implications for fertilization biology.
The Biological Bulletin; 10/1/2002; Eckelbarger, Kevin J. Young, Craig M.; 4964 words
; ... fine needle and examining the extruded coelomic contents under a compound microscope for ... sections of 2-4 body segments containing coelomic sperm or ovaries. The tissue samples were ... vitellogenesis, when they are released into the coelom. Sexually mature females were so packed ...
Read more
|
Related entries from encyclopedias, dictionaries, and thesauruses
|
coelom
A Dictionary of Zoology
coelom A fluid-filled (see COELOMIC FLUID ) body cavity that originates by the splitting of the mesoderm ... to be differentiated for various functions. In many animals, the coelom plays an important part in collecting excretions and acts as a storage ...
Read more
|
|
Body Cavities
Animal Sciences
... There is no secondary body cavity, or coelom, and consequently these phyla are referred ... not all of the characteristics of true coeloms. Finally, several animal phyla, including ... characterized by a body cavity known as a true coelom . These phyla are known as the eucoelomates ...
Read more
|
|
|
Body Plan
Animal Sciences
... Nemertea No pseudocoele, body is acoelomate, has coelom-like structure for storing proboscis, complete ... segmentation. Coelomates have internal body cavities (coeloms) Phylum Annelidabody cavities (coeloms) Triploblastic, segmentation and body segment ...
Read more
|
|
|
Annelida
A Dictionary of Zoology
Annelida A phylum of coelomate (see COELOM ) worms that have a definite head and good metameric segmentation . Anatomically they are more complex than the Platyhelminthes . They have vascular, respiratory, and nervous systems which are well developed ...
Read more
|
|
|
Echiurida
A Dictionary of Zoology
Echiurida (spoon worms) A phylum of coelomate (see COELOM ), marine, worm-like animals in which mature individuals lack metameric segmentation . The body consists of a sausage-shaped, cylindrical trunk and an anterior, muscular proboscis that cannot ...
Read more
|