The digestive tract of the echinopluteus of Echinocardium cordatum (Echinodermata, Echinoida): its ultrastructure and innervation

1994 ◽  
Vol 72 (12) ◽  
pp. 2090-2099 ◽  
Author(s):  
Leonid P. Nezlin ◽  
Vladimir V. Yushin

The digestive tract of the echinopluteus of Echinocardium cordatum consists of a tubular oesophagus, spherical stomach, and large hemispherical intestine. The oesophagus is constructed from cells of one ultrastructural type and has subepithelial muscles oriented circumferentially and longitudinally. The cardiac and pyloric sphincters separating the stomach from the oesophagus and intestine, as well as the anal sphincter, consist of myoepithelial cells and subepithelial muscles. The cells of both the stomach and intestine are able to absorb nutrients and phagocytize food. Neuron-like cells were detected around the mouth, in the oesophageal epithelium, and around the anal opening. Axonal trunks pass at the base of the oesophageal epithelium and around the sphincters. The rest of the digestive tract is innervated by solitary axons. Catecholamine-containing neurons were found inside the lower lip ganglion, in the two suboral ganglia, and around the anal opening.

2003 ◽  
Vol 11 (3) ◽  
pp. 192-202 ◽  
Author(s):  
Mirian Aparecida Onofre ◽  
Heli Benedito Brosco ◽  
Rumio Taga

The objective of the present study was to evaluate the glands of wall of congenital fistulae of the lower lip with the transmission electron microscope in order to characterize their microstructural pattern. Thin section of Araldite resin embedded congenital fistulae of the lower lip of four patients with Van der Woude syndrome from the Hospital de Reabilitação de Anomalias Craniofaciais da Universidade de São Paulo, Bauru, SP, were analyzed with a transmission electron microscope. The results showed that the glands were mostly made by typical mucous acini exhibiting, with certain frequency, myoepithelial cells surrounding them. In some of lobules, a few acini smaller than the typical mucous, showed granules of moderate electron density or containing a dense core or exhibiting small dense spherule and predominance granular material. These granules resemble to described recently by others in various human minor salivary glands. We concluded that glands associated with congenital fistula of lower lip of patients with Van der Woude syndrome, in spite of being located in vermilion border of the lip, showed at the transmission electron microscope characteristics of labial minor salivary gland, i.e, are mostly mucous with a few seromucous units, while typical seromucous demilunes are not present.


1986 ◽  
Vol 64 (9) ◽  
pp. 1842-1851 ◽  
Author(s):  
Geneviève Lutaud

Blue lateral spots, corresponding to rows of myoepithelial cells invaded by spherular pigmented microorganisms, were observed in the oesophagus of every polypide in 75% of living colonies of Palmicellaria skenei from deep rocky sites off the northern coast of Brittany. Ultrastructural examination of the microorganisms showed that they are intracellular procaryonts with no membranous organelle of thylakoid structure. Their natural pigmentation and a cortical layer of vesicles cause them to resemble autotrophic bacteria with chlorophyllic pigments. The association is not obligatory, but it is specific and is restricted to the first contractile region of the digestive tract. Ultrastructural examination of the paired organs attached to the diaphragm of the tentacular sheath showed that each organ is formed by the adhesion of one of the glandular diverticula of the diaphragm to a pouch, itself derived from the vestibular wall and containing filamentous bacteria, which is divided by the folds of its internal cuticle. The structural characters of the bacteria are described. The interdigitated microvilli of the epithelium of this pouch and the presence inside it of fibrillated plates, probably originating from the adjacent secretory organ, suggest that there may be exchanges between the bacterial population and the host. The association is obligatory and probably symbiotic.


Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2651-2659 ◽  
Author(s):  
T. Kondo ◽  
P. Dolle ◽  
J. Zakany ◽  
D. Duboule

Vertebrate 5′-located HoxD genes are expressed in the most caudal part of the digestive tract and their potential functions during gut development have been assessed by gene disruptions. We have inserted reporter lacZ sequences within the Hoxd-12 gene and analysed the morphology of the gut in these mice as well as in Hoxd-13 mutant animals. When homozygous, both mutations induce an important disorganization of the anorectal region. In particular, severe alterations of the smooth muscle layers of the rectum led to defective morphogenesis of the internal anal sphincter. Similarly, Hoxd-12 and Hoxd-13 functionally overlap during digit development. The function of these genes in the morphogenesis of the digestive system as well as their functional evolution are discussed.


2000 ◽  
Vol 5 (1) ◽  
Author(s):  
S. RODASKI ◽  
S. D. GUÉRIOS ◽  
M. A. PERRONI ◽  
A. B. NARDI ◽  
C. A. M. SILVA

A incontinência fecal em cães pode ser neurogênica ou conseqüente às miopatias da região perineal, principalmente em relação ao esfíncter anal externo. Nas extensas ressecções como nos casos de neoplasias perineais, pode haver comprometimento do esfíncter anal externo e inabilidade para retenção de fezes. Tendo em vista a dificuldade dos proprietários conviverem com animais incontinentes, este experimento tem como objetivo restabelecer a função do músculo esfíncter anal externo com enxerto de membrana biológica conservada em glicerina 98%. Trinta dias após iatrogenização de incontinência através da miectomia bilateral do esfíncter anal externo, procedeu-se a esfincteroplastia. Para isso foram realizadas duas incisões de 2 cm, laterais a abertura anal, e através dessas foram feitos dois túneis no tecido subcutâneo, um dorsal e outro ventral, com o auxílio de pinça hemostática curva de Halstead. Após a tunilização, inseriu-se um segmento de peritônio bovino medindo em média 6 cm de comprimento e 0,5 cm de largura. As extremidades da membrana foram unidas através de duas suturas interrompidas simples, e após isto, fixou-se o peritônio ao músculo coccígeo com três suturas interrompidas simples e fio polipropileno no. 3-0. Na seqüência, procedeu-se a sutura contínua simples do tecido subcutâneo com fio categute simples no. 3-0 e aproximou-se as bordas da pele através de suturas interrompidas simples com fio mononáilon no. 3-0. Os dez cães, machos, sem raça definida, com peso variando entre 8 e 12 kg apresentaram controle da emissão de fezes em 10 dias, após a realização da esfincteroplastia, e permaneceram continentes durante os dois meses de observação pós-operatória. External anal experimental esphincteroplasty in dogs with bovine peritoneum membrane preserved in 98% glicerine Abstract Fecal incontinence in dogs can be either neurogenic or due to myopathies in the perineal region, mainly in relation to the external anal sphincter. In large resections as in cases of perineal neoplasias, there may be damage of the external anal sphincter and incapability of fecal control. Once it is hard for owners to cope with incontinent animals, this experiment objectifies to re-establish the functioning of the muscle of the external anal sphincter by grafting a biological membrane preserved in glycerine 98%. Sphincteroplasty was held 30 days after incontinence iatrogeny, through a bilateral myectomy of the external anal sphincter. Two incisions of 2cm at both sides of the anal opening were performed, followed by two ventral and dorsal tunnels opened through the subcutaneous tissue using Halsted’s curved hemostatic forceps. After tunneling, a segment of bovine peritoneum was inserted, 6 cm long and 0,5 cm wide, Membrane ends were put together by two plain interrupted sutures and after this procedure, peritoneum was attached to coccigean muscle by three plain interrupted sutures with polypropylene thread no. 3-0. It was followed by a plain continuous suture of the subcutaneous tissue with catgut no.3-0, putting dermal ends together through plain interrupted sutures with mononylon thread no. 3-0. Ten (10) male dogs of undefined breed, weight ranging from 8 to 12 kg presented fecal control ten days after sphincteroplasty and remained continent for the two subsequent months of follow-up.


Author(s):  
Gauthier Rolet ◽  
Alexander Ziegler ◽  
Chantal De Ridder

Heart urchins (Echinoidea: Spatangoida) are considered infaunal, deposit feeding sea urchins that utilize the surrounding sediment as a source of nutrients. Sediment occupies most of the digestive tract lumen but never enters the gastric caecum, a prominent structure that is filled with a transparent fluid. The aim of this study was to shed light on the nature of the fluid found inside the gastric caecum of a well-studied spatangoid species, Echinocardium cordatum. Our conclusions are based on a three-step-approach: firstly, by following the movement of dyed seawater from the mouth up to the caecal lumen; secondly, by comparing the osmolarity of various body fluids; and thirdly, by describing the particulate content of the gastric caecum. In addition, we employed magnetic resonance imaging (MRI) to reveal the absence of sediment within the gastric caecum. Our osmolarity measurements show that the coelomic fluid is significantly more concentrated than the caecal fluid, which in turn has an osmolarity similar to seawater. MRI reveals that the gastric caecum, in contrast to the rest of the digestive tract, is always devoid of sediment. Light and electron microscopy observations reveal the presence of a variety of detrital particles suspended in the caecal fluid that are identical to those occurring in seawater sampled over the seafloor. We argue that the fluid filling the gastric caecum must be predominantly seawater, and we propose a scenario that explains seawater circulation in E. cordatum. In this context, the gastric caecum could act as an internal trap for suspended particulate organic matter. We hypothesize that spatangoid sea urchins could have adopted internal suspension feeding as a secondary feeding mode in addition to deposit feeding.


Author(s):  
Alfredo Feria-Velasco ◽  
Guadalupe Tapia-Arizmendi

The fine structure of the Harderian gland has been described in some animal species (hamster, rabbit, mouse, domestic fowl and albino rats). There are only two reports in the literature dealing on the ultrastructure of rat Harderian gland in adult animals. In one of them the author describes the myoepithelial cells in methacrylate-embbeded tissue, and the other deals with the maturation of the acinar cells and the formation of the secretory droplets. The aim of the present work is to analize the relationships among the acinar cell components and to describe the two types of cells located at the perifery of the acini.


Author(s):  
C. N. Sun

Myoepithelial cells have been observed in the prostate, harderian, apocrine, exocrine sweat and mammary glands. Such cells and their numerous branching processes form basket-like structures around the glandular acini. Their shapes are quite different from structures seen either in spindleshaped smooth muscle cells or skeletal muscle cells. These myoepithelial cells lie on the epithelial side of the basement membrane in the glands. This presentation describes the ultrastructure of such myoepithelial cells which have been found also in the parotid gland carcinoma from a 45-year old patient.Specimens were cut into small pieces about 1 mm3 and immediately fixed in 4 percent glutaraldehyde in phosphate buffer for two hours, then post-fixed in 1 percent buffered osmium tetroxide for 1 hour. After dehydration, tissues were embedded in Epon 812. Thin sections were stained with uranyl acetate and lead citrate. Ultrastructurally, the pattern of each individual cell showed wide variations.


Author(s):  
T. M. Murad ◽  
E. von Haam

Pericytes are vascular satellites present around capillary blood vessels and small venules. They have been observed in almost every tissue of the body and are thought to be related to vascular smooth muscle cells. Morphologically pericytes have great similarity to vascular endothelial cells and also slightly resemble myoepithelial cells.The present study describes the ultrastructural morphology of pericytes in normal breast tissue and in benign tumor of the breast. The study showed that pericytes are ovoid or elongated cells separated from the endothelial cell of the capillary blood vessel by the basement membrane of endothelial cell. The nuclei of pericytes are often very distinctive. Although some are round, oval, or elongated, others show marked irregularity and infolding of the nuclear membrane. The cytoplasm shows mono-or bipolar extension in which the cytoplasmic organelles are located (Fig. 1). These cytoplasmic extensions embrace the capillary blood vessel incompletely. The plasma membrane exhibits multiple areas of focal condensation called hemidesmosomes (Fig. 2, arrow). A variable number of pinocytotic vesicles are frequently seen lining the outer plasma membrane. Normally pericytes are surrounded by a basement membrane which is found more consistently on the outer plasma membrane separating the pericytes from the stromal connective tissue.


1970 ◽  
Vol 101 (2) ◽  
pp. 241-244 ◽  
Author(s):  
L. M. Solomon
Keyword(s):  

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