Anatomy and Histology of the Gut of the Emu <i>Dromaius Novaehollandiae</i>

Herd, R. M.

doi:10.1071/mu9850043

Cited by 9 publications

(9 citation statements)

References 10 publications

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“…These features are shared by ratites and have been reported in the ostrich (Gadow, 1879; Pernkopf and Lehner, 1937; Tivane, 2008), greater rhea (Gadow, 1879; Feder, 1972), kiwi (Owen, 1879; Pernkopf and Lehner, 1937) and cassowary (Meckel, 1829; Gadow, 1879). As previously noted by Herd (1985), the lumen of the proximal oesophagus of the emu exhibits a series of well‐developed longitudinal folds. An average number of 16‐folds were present in the emu oesophagus in comparison with 10–12 in the greater rhea (Feder, 1972) and 12 in the ostrich (Tivane, 2008).…”

Section: Discussionsupporting

confidence: 59%

“…Another important adaptation of the oesophagus for swallowing large food items is that of lubrication (Ziswiler and Farner, 1972; Hodges, 1974). This is made possible in the emu by the ubiquitous presence of mucus‐secreting glands in the lamina propria (Herd, 1985; M. R. Crole, personal observation). Thus, the proximal oesophagus of the emu displays three main adaptations allowing it to receive and handle large, orally unaltered, food items: (1) the diameter is relatively large, (2) the mucosa is longitudinally folded allowing great distensibility and (3) the numerous mucus‐secreting glands provide copious amounts of mucus to lubricate the lumen and food for ease of transport.…”

Section: Discussionmentioning

confidence: 99%

“…Although aspects of the anatomy of ratites have been the subject of recent in‐depth investigations (Aire et al., 2008; Parizzi et al., 2008) and despite numerous studies conducted on the intestinal tract (Owen, 1841, 1879; Gadow, 1879; Pycraft, 1900; Mitchell, 1901; Herd, 1985; Bezuidenhout, 1986, 1999; Potter et al., 2006; Porchescu, 2007), very little comprehensive information is available on the structure of the upper digestive tract (oral cavity, tongue, pharynx and oesophagus) of these birds. In contrast, the upper digestive tract of many other avian species has been described in some detail (for a review of the earlier literature see Calhoun, 1954; McLelland, 1979).…”

Section: Introductionmentioning

confidence: 99%

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Gross Morphology of the Intra‐Oral rhamphotheca, Oropharynx and Proximal Oesophagus of the Emu (Dromaius novaehollandiae)

Crole

Soley

2010

Anat Histol Embryol

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Information on the gross morphology of the upper digestive tract of ratites is sparse. This is an important region considering that it is the first area for food selection and intake which is vital to the nutrition and growth of the animal and therefore its commercial viability. Twenty-three heads from sub-adult (12-14 months) emus were used to provide a definitive description of the oropharynx and proximal oesophagus. Besides supplying baseline morphological data of veterinary importance, this study also underlines the functional importance of this region. The mandibular and maxillary nails, and serrations on the rostral mandibular tomia, provide the emu with a formidable combination of gripping, tearing and pecking power. The folded oropharyngeal floor allows distention of the dorso-ventrally flattened cavity during eating and drinking. The laryngeal mound performs both respiratory and digestive functions, whereas the distensible proximal oesophagus supports the particular feeding method employed by ratites.

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Section: Discussionsupporting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gross Morphology of the Intra‐Oral rhamphotheca, Oropharynx and Proximal Oesophagus of the Emu (Dromaius novaehollandiae)

Crole

Soley

2010

Anat Histol Embryol

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“…Proximal esophagus A prominent feature of the avian esophagus is the presence of numerous simple tubular mucus‐secreting glands, a feature also noted in the ostrich (Tivane 2008) and greater rhea (Feder 1972). In the emu, the esophageal glands are situated in the Lamina propria (Herd 1985) (although much of their length is enclosed in the epithelial lining) (present study) into which they extend for only a short distance, a feature similar to that in the ostrich (Porchescu 2007; Tivane 2008) and greater rhea (Feder 1972). This is in contrast to mammals where glands are situated in the submucosa (Ross and Pawlina 2006).…”

mentioning

confidence: 71%

“…Studies on the upper digestive tract of ratites have identified glandular tissue in the ostrich ( Struthio camelus ) (Porchescu 2007; Jackowiak and Ludwig 2008; Tivane 2008), greater rhea ( Rhea americana ) (Feder 1972) and emu ( Dromaius novaehollandiae ) (Herd 1985; Crole and Soley 2009a, b, c, 2010b). However, with the exception of a detailed report on the lingual glands of the emu (Crole and Soley 2009 c ) very little comprehensive information is available on the morphology and distribution of glandular tissue in the oropharynx and proximal esophagus in this group of birds.…”

Section: Introductionmentioning

confidence: 99%

Distribution and structure of glandular tissue in the oropharynx and proximal esophagus of the emu (Dromaius novaehollandiae)

Crole

Soley

2010

Acta Zoologica

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The glandular regions of the upper digestive tract in the emu were non-pigmented (except for the tongue in most specimens) and invested by a non-keratinised stratified squamous epithelium. The glands found in these regions were exclusively simple in nature and composed of tubular secretory units lined by Periodic Acid Schiff Stain-positive mucus-secreting cells. The naming of the various glandular fields was based on previously identified anatomical features and on nomenclature modified from previous studies on birds. The glands were classified into two main types, namely, simple tubular and simple branched tubular mucus-secreting glands. Simple branched tubular glands were a feature of the regions exposed to the greatest amount of friction during feeding, whereas simple tubular glands were a feature of regions exposed to less friction. The saliva produced by the salivary glands in birds functions to moisturize and lubricate food boli. Mucins in saliva also protect mucosal surfaces from desiccation and mechanical damage, assist in maintaining cellular water balance, provide lubrication and have an antimicrobial action. This study suggests that, in addition to the role of specific gross anatomical features, the type and distribution of glandular tissue in the emu upper digestive tract supports the cranioinertial feeding method employed by this species.

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The avian cecum: Update and motility review

1999

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The ceca, intestinal outpocketings of the gut, are described, classified by types, and their occurrence surveyed across the Order Aves. Correlation between cecal size and systematic position is weak except among closely related species. With many exceptions, herbivores and omnivores tend to have large ceca, insectivores and carnivores are variable, and piscivores and graminivores have small ceca. Although important progress has been made in recent years, especially through the use of wild birds under natural (or quasi-natural) conditions rather than studying domestic species in captivity, much remains to be learned about cecal functioning. Research on periodic changes in galliform and anseriform cecal size in response to dietary alterations is discussed. Studies demonstrating cellulose digestion and fermentation in ceca, and their utilization and absorption of water, nitrogenous compounds, and other nutrients are reviewed. We also note disease-causing organisms that may be found in ceca. The avian cecum is a multi-purpose organ, with the potential to act in many different ways-and depending on the species involved, its cecal morphology, and ecological conditions, cecal functioning can be efficient and vitally important to a bird' s physiology, especially during periods of stress.

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Anatomy and Histology of the Gut of the Emu Dromaius Novaehollandiae

Cited by 9 publications

References 10 publications

Gross Morphology of the Intra‐Oral rhamphotheca, Oropharynx and Proximal Oesophagus of the Emu (Dromaius novaehollandiae)

Gross Morphology of the Intra‐Oral rhamphotheca, Oropharynx and Proximal Oesophagus of the Emu (Dromaius novaehollandiae)

Distribution and structure of glandular tissue in the oropharynx and proximal esophagus of the emu (Dromaius novaehollandiae)

The avian cecum: Update and motility review

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