Biomaterial Database

Ultrastructure of the secondary yolk sac in pig's embryo. 1994

J Liwska, and A J Grabiński-Baranowski

Department of Histology and Embryology, Veterinary Faculty Agricultural University, Warsaw.

During the investigated period of development the pig embryo secondary yolk sac consists of two parallel epithelia (endodermal and mesodermal) separated by a layer of vascularized mesenchyme. Endoderm cells and blood vessels undergo morphological changes connected with the embryo age. The development of the blood vessels is at the vasculogenesis stage. Blood stem cells, erythroblasts, megakaryocytes and platelets were observed in the lumen of vessels. A comparison our results with the development of the pig embryo liver shows that the transferring the haemopoetic function from the yolk sac to the liver begins on about 27 dpc. Until 51 day of embryo development the yolk sac does not show any signs of involution. Possibly yolk sac supports the liver in its haemopoetic function until the time when that organ becomes a fully efficient haemopoetic organ.

UI	MeSH Term	Description	Entries
D005314	Embryonic and Fetal Development	Morphological and physiological development of EMBRYOS or FETUSES.	Embryo and Fetal Development,Prenatal Programming,Programming, Prenatal
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D015017	Yolk Sac	The first of four extra-embryonic membranes to form during EMBRYOGENESIS. In REPTILES and BIRDS, it arises from endoderm and mesoderm to incorporate the EGG YOLK into the DIGESTIVE TRACT for nourishing the embryo. In placental MAMMALS, its nutritional function is vestigial; however, it is the source of INTESTINAL MUCOSA; BLOOD CELLS; and GERM CELLS. It is sometimes called the vitelline sac, which should not be confused with the VITELLINE MEMBRANE of the egg.	Vitelline Sac of Embryo,Embryo Vitelline Sac,Embryo Vitelline Sacs,Sac, Yolk,Sacs, Yolk,Yolk Sacs