Biomaterial Database

Histology and ultrastructure of the chorioallantoic membrane of the mallard duck (Anas platyrhynchos). 2000

W S Lusimbo, and F A Leighton, and G A Wobeser

Department of Veterinary Pathology and Canadian Co-operative Wildlife Health Centre, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B4 Canada. Wanjala.lusimbo@usask.ca

The histology and fine structure of the chorioallantoic membrane of the mallard duck (Anas platyrhynchos), and the density of vessels per millimeter of membrane were assessed between days 12 and 24 of incubation. Light and transmission electron microscopy of the chorioallantoic membrane of the mallard duck after various days of incubation was carried out. Blood vessels within the mesoderm were counted per millimeter of membrane by light microscopy (40x). The chorioallantoic membrane had three distinct layers from day 12 to 24 of incubation, the chorionic epithelium, the mesoderm, and the allantoic epithelium. After day 12, chorionic epithelium consisted of two layers of flattened, elongated epithelial cells interfaced by numerous desmosomes, and separated from the underlying mesoderm by a basement membrane. At this stage, the allantoic epithelium consisted of a single layer of flattened, overlapping cells. Blood capillaries were observed in the mesoderm close to the chorionic epithelium on days 12 and 13; by day 14, these capillaries were located within the chorionic epithelium, forming a capillary sinus. Between days 14 and 16, the chorion underwent cellular and cytological differentiation into three cell types: capillary covering cells, villus cavity cells, and less differentiated basal cells. The mesoderm was composed of a loose matrix of mesenchymal cells and collagen fibrils through which coursed blood and lymphatic vessels. The vascular density in the mesoderm increased rapidly from 4.2+/-0.6 vessels per mm (n = 12) on day 12 to a maximum of 9.4+/-0.3 vessels per mm (n = 15) by day 16. From day 16, the allantoic epithelium had two to three layers of elongated and overlapping cells. The luminal layer of allantoic epithelial cells had microvillus projections and varying numbers of membrane-bound dense vesicles at all stages from day 12 onward. The histologic and ultrastructural features of mallard duck chorioallantoic membrane from day 12 to 24 of incubation were very similar to those described in the chorioallantoic membrane of the chicken (Gallus gallus) from day 8 to 20 of incubation. Much of the information available concerning the CAM of the chicken also may apply to the CAM of the mallard, with timing adjusted to match the developmental time-frame recorded here.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D010063	Ovum	A mature haploid female germ cell extruded from the OVARY at OVULATION.	Egg,Egg, Unfertilized,Ova,Eggs, Unfertilized,Unfertilized Egg,Unfertilized Eggs
D002823	Chorion	The outermost extra-embryonic membrane surrounding the developing embryo. In REPTILES and BIRDS, it adheres to the shell and allows exchange of gases between the egg and its environment. In MAMMALS, the chorion evolves into the fetal contribution of the PLACENTA.	Chorions
D004195	Disease Models, Animal	Naturally-occurring or experimentally-induced animal diseases with pathological processes analogous to human diseases.	Animal Disease Model,Animal Disease Models,Disease Model, Animal
D004372	Ducks	A water bird in the order Anseriformes (subfamily Anatinae (true ducks)) with a broad blunt bill, short legs, webbed feet, and a waddling gait.	Duck
D004528	Egg Shell	A hard or leathery calciferous exterior covering of an egg.	Eggshell,Egg Shells,Eggshells,Shell, Egg,Shells, Egg
D004625	Embryo, Nonmammalian	The developmental entity of a fertilized egg (ZYGOTE) in animal species other than MAMMALS. For chickens, use CHICK EMBRYO.	Embryonic Structures, Nonmammalian,Embryo, Non-Mammalian,Embryonic Structures, Non-Mammalian,Nonmammalian Embryo,Nonmammalian Embryo Structures,Nonmammalian Embryonic Structures,Embryo Structure, Nonmammalian,Embryo Structures, Nonmammalian,Embryo, Non Mammalian,Embryonic Structure, Non-Mammalian,Embryonic Structure, Nonmammalian,Embryonic Structures, Non Mammalian,Embryos, Non-Mammalian,Embryos, Nonmammalian,Non-Mammalian Embryo,Non-Mammalian Embryonic Structure,Non-Mammalian Embryonic Structures,Non-Mammalian Embryos,Nonmammalian Embryo Structure,Nonmammalian Embryonic Structure,Nonmammalian Embryos,Structure, Non-Mammalian Embryonic,Structure, Nonmammalian Embryo,Structure, Nonmammalian Embryonic,Structures, Non-Mammalian Embryonic,Structures, Nonmammalian Embryo,Structures, Nonmammalian Embryonic
D004785	Environmental Pollutants	Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.	Environmental Pollutant,Pollutant,Pollutants,Pollutants, Environmental,Pollutant, Environmental
D000367	Age Factors	Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.	Age Reporting,Age Factor,Factor, Age,Factors, Age
D000482	Allantois	An extra-embryonic membranous sac derived from the YOLK SAC of REPTILES; BIRDS; and MAMMALS. It lies between two other extra-embryonic membranes, the AMNION and the CHORION. The allantois serves to store urinary wastes and mediate exchange of gas and nutrients for the developing embryo.	Allantoic Membrane,Membrane, Allantoic