somite

[′sō‚mīt]

(zoology)

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Somite

a paired metameric formation in the embryos of such invertebrates as annelids and insects and in the embryos of man and all other chordates. The middle germ layer, or mesoderm, is segmented into somites during embryonic development. The somites are arranged along the longitudinal axis of the body alongside the neural tube and the chorda. The entire mesoderm is segmented in invertebrates, whereas in man and other chordates only its dorsal section is segmented, with the remaining mesoderm forming lateral plates, or splanchnotomes. Segmentation begins from the anterior section of the body and gradually extends to the posterior section. In the process of development, each somite decomposes into a myotome, a sclerotome, and a dermatome, from which are formed, respectively, the truncal musculature, the axial skeleton (in fish, also the skeleton of the fins), and the connective-tissue portion of the skin and its derivatives.

T. A. DETLAF

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References in periodicals archive

Shh is a gene involved in different processes of embryonic development, as the induction of the neural tube, differentiation of the somites, and regionalization of the intestine (Sadler, 2012), it is also related to a center of signals involved in the anteroposterior formation members design (Johnson et al., 1994; Antonelli et al., 2012).

Immunolocalization of Morphogen Sonic Hedgehog in Salmon Fry (Salmo salar)/Inmunolocalizacion del Morfogeno Sonic Hedhehog en Alevines de Salmon (Salmo salar)

Higher exposure concentrations resulted in progressively higher GFP expression levels, and a nominal concentration of [EE.sub.2] (10 ng/L; measured concentration, 7.25 ng/L) induced considerable expression throughout the liver; this was accompanied by GFP expression in the muscle (somite and cranial muscle) and heart (Figure 3D).

Biosensor zebrafish provide new insights into potential health effects of environmental estrogens

The focus of these experiments was to achieve survival of the embryos following somite:somite cross-transplantation through 10 days post-surgery, which provides the opportunity for the embryo to complete pattern formation, and establish the basic body plan.

Avian somitic cell chimeras using surrogate eggshell technology

6, A and B): Dorsomedian spines on the 4th, 5th and 6th abdominal somites; one pair of lateral spines on 5th and 6th abdominal somites; one pair of lateroventral spines on the 6th abdominal somite.

Larval development of the kishi velvet shrimp, Metapenaeopsis dalei (Rathbun) (Decapoda: Penaeidae), reared in the laboratory

Abdomen extremely large, with six somites, and telson free articulated; margin with tomentum, laterally covering ischia and distally buccal cavity and eyes.

Austinotheres angelicus (Lockington, 1877): nombre correcto para el cangrejo simbiotico Juxtafabia muliniarum sensu Cabrera-Pena et al

acanthitelsonis herein examined, from north and south Atlantic, do not vary in the characters mentioned in the identification key of Crosnier & Forest (1973) presenting: smooth dorsal margin at abdominal somites 3-5; abdominal somite 2 without dorsal carina; long and slender rostrum; and 13-19 pairs of dorsolateral spines at telson.

Sobre algunos Oplophoridae (Caridea, Decapoda) raros de la Cordillera Meso-Atlantica Sur

Nonsignificant malformations (otic vesicle, somite, circulation, pigmentation, swim bladder, notochord distortion, and alterations in touch response) are excluded.

Signaling Events Downstream of AHR Activation That Contribute to Toxic Responses: The Functional Role of an AHR-Dependent Long Noncoding RNA (slincR) Using the Zebrafish Model

The upper distal borders of the fifth abdominal somite have a spine on each side that was only visible on the right-hand side of the prezoea stage.

The larval development from prezoea to megalopa and juvenile stages of Allopetrolisthes punctatus (Guerin, 1835) (Decapoda, Anomura, Porcellanidae)

Citation: Taketaro Sadahiro et al., Tbx6 Induces Nascent Mesoderm from Pluripotent Stem Cells and Temporally Controls Cardiac versus Somite Lineage Diversification.

Tbx6 Is Crucial To Heart And Skeleton Formation From Stem Cells

(A) Habitus, dorsal view; (B) Urosome showing posterior end of the genital double-somite, the anal somite, and caudal rami, ventral view; (C) Caudal ramus, dorsal view; (D) Leg 5.

First Record of the Family Peltidiidae (Copepoda; Harpacticoida) from the Gulf of Mexico, with the Description of a New Species of Peltidium

The above are in line with the observed complexity of the embryological development of the vertebral skeleton, which encompasses abnormalities that can arise at any stage from the somite development through the ossification of the cartilage anlage (primordium stage of development).

The Articulating Neural Arch A Rare Developmental Anomaly

Urosome with four segments, genital double somite subquadrate, lacking lateral medial protrusions and with rounded integumental window on each side of posterior half (arrows in Fig.

Notas sobre Halicyclops (Copepoda, Cyclopoida, Cyclopidae) de Colombia y el Caribe occidental: un nuevo registro con una clave para las especies del Grupo "B" sensu Rocha (1991)