title: Light and electron microscopy of the European beaver (Castor fiber) stomach reveal unique morphological features with possible general biological significance.
abstract: Anatomical, histological, and ultrastructural studies of the European beaver stomach revealed several unique morphological features. The prominent attribute of its gross morphology was the cardiogastric gland (CGG), located near the oesophageal entrance. Light microscopy showed that the CGG was formed by invaginations of the mucosa into the submucosa, which contained densely packed proper gastric glands comprised primarily of parietal and chief cells. Mucous neck cells represented <0.1% of cells in the CGG gastric glands and 22-32% of cells in the proper gastric glands of the mucosa lining the stomach lumen. These data suggest that chief cells in the CGG develop from undifferentiated cells that migrate through the gastric gland neck rather than from mucous neck cells. Classical chief cell formation (i.e., arising from mucous neck cells) occurred in the mucosa lining the stomach lumen, however. The muscularis around the CGG consisted primarily of skeletal muscle tissue. The cardiac region was rudimentary while the fundus/corpus and pyloric regions were equally developed. Another unusual feature of the beaver stomach was the presence of specific mucus with a thickness up to 950 µm (in frozen, unfixed sections) that coated the mucosa. Our observations suggest that the formation of this mucus is complex and includes the secretory granule accumulation in the cytoplasm of pit cells, the granule aggregation inside cells, and the incorporation of degenerating cells into the mucus.
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Ziółkowska
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Lewczuk
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Petryński
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Palkowska
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Prusik
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Targońska
authors.affiliation: 2Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland.
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Giżejewski
authors.affiliation: Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Przybylska-Gornowicz
mesh_terms: D000818:Animals; D005753:Gastric Mucosa / Q000166:cytology / Q000648:ultrastructure; D012377:Rodentia; D013270:Stomach / Q000033:anatomy & histology / Q000166:cytology* / Q000648:ultrastructure*
references.citation: Z Mikrosk Anat Forsch. 1990;104(2):298-304
references.pmid: 2220027
references.citation: Anat Rec. 1993 Jun;236(2):297-313
references.pmid: 8338234
references.citation: Annu Rev Microbiol. 1987;41:435-64
references.pmid: 3318676
references.citation: Clin Sci (Lond). 1982 Aug;63(2):187-95
references.pmid: 6806004
references.citation: Q J Exp Physiol. 1984 Jul;69(3):615-25
references.pmid: 6473699
references.citation: Anat Rec. 1993 Jun;236(2):314-32
references.pmid: 8338235
references.citation: Cell Tissue Res. 1998 Jul;293(1):121-31
references.pmid: 9634604
references.citation: Gastroenterology. 2010 Dec;139(6):2038-49
references.pmid: 20816838
references.citation: C R Biol. 2008 Jan;331(1):32-41
references.pmid: 18187120
references.citation: Histochem J. 1991 Jan;23(1):22-8
references.pmid: 1718927
references.citation: Anat Rec. 1996 Jul;245(3):539-58
references.pmid: 8800413
references.citation: Am J Physiol Cell Physiol. 2005 Jan;288(1):C1-19
references.pmid: 15591243
references.citation: Development. 2007 Jan;134(1):211-22
references.pmid: 17164426
references.citation: Cell Tissue Res. 1983;233(3):475-84
references.pmid: 6194886
references.citation: Anat Histol Embryol. 1997 Sep;26(3):217-22
references.pmid: 9334501
references.citation: Anat Histol Embryol. 2005 Dec;34(6):373-8
references.pmid: 16288608
references.citation: Eur J Pharm Sci. 2010 Jul 11;40(4):335-41
references.pmid: 20417275
references.citation: C R Acad Sci III. 1999 Dec;322(12):1081-92
references.pmid: 10656148
references.citation: Anat Histol Embryol. 2010 Oct;39(5):432-9
references.pmid: 20645954
references.citation: J Pharm Pharmacol. 2012 Feb;64(2):218-27
references.pmid: 22221097
references.citation: Acta Anat (Basel). 1974;88(1):1-10
references.pmid: 4838366
references.citation: Exp Cell Res. 2011 Nov 15;317(19):2759-64
references.pmid: 21907708
references.citation: Anat Anz. 1987;163(4):311-8
references.pmid: 2888419
references.citation: J Histochem Cytochem. 1965 Mar;13:211-34
references.pmid: 14327695