are gestational sac and yolk sac the same
Gestational sac The yolk sac and embryo should be readily identifiable when the gestational sac reaches a certain size â€” a yolk sac should be seen when the gestational sac is 20mm and a fetal pole should be seen when the gestational sac reaches 25mm.
Fetal pig The monogastric digestive system of the fetal pig harbors many similarities with many other mammals. The fetal pig's digestive organs are well developed before birth, although it does not ingest food. These organs include the esophagus, stomach, small and large intestines. Mesenteries serve to connect the organs of the fetal pig together. In order for digestion to occur, the fetal pig would have to ingest food. Instead, it gains much needed nutrition from the mother pig via the umbilical cord. In the adult pig, food will follow the general flow through the esophagus, which can be located behind the tracheae. From the oral cavity, the esophagus leads to the stomach, small intestine, and large intestine. Other organs developing during fetal pig development such as the gallbladder, pancreas and spleen are all critical in contributing to the overall flow of the digestive system because they contain digestive enzymes that will perform chemical digestion of food. After food is digested and nutrients are absorbed, the food follows through the large intestine and solid wastes are excreted through the anus. In the fetal pig however, the metabolic wastes are sent back to the mother through the umbilical cord where the mother excretes the wastes. Other remaining wastes remain in the fetal pig until birth. Then