The primitive gut tube is derived from the dorsal part of the yolk sac , which is incorporated into the body of the embryo during folding of the embryo during the fourth week.
The primitive gut tube is divided into three sections. Table 11 - Sections of the Gut Tube. Pharynx, lower respiratory system, esophagus, stomach, proximal half of duodenum, liver and pancreas, biliary apparatus.
Small intestine, distal half of duodenum, cecum and vermiform appendix, ascending colon, most of the transverse colon. Left part of transverse colon, descending colon, sigmoid colon, rectum, superior part of anal canal, epithelium of urinary bladder, most of the urethra. The epithelium of and the parenchyma of glands associated with the digestive tract e.
During the solid stage of development the endoderm of the gut tube proliferates until the gut is a solid tube. A process of recanalization restores the lumen. The proctodeum anal pit is the primordial anus , and the stomodeum is the primordial mouth. In both of these areas ectoderm is in direct contact with endoderm without intervening mesoderm, eventually leading to degeneration of both tissue layers.
The tracheoesophageal septum divides the foregut into the esophagus and trachea. See the chapter on Respiratory system for more information. The primordium of the primitive stomach is visible about the end of the fourth week. It is initially oriented in the median plane and suspended from the dorsal wall of the abdominal cavity by the dorsal mesentery or mesogastrium. Rotation of the stomach creates the omental bursa or lesser peritoneal sac. The duodenum acquires its C-shaped loop as the stomach rotates.
AccessEmergency Medicine. Case Files Collection. Clinical Sports Medicine Collection. Davis AT Collection. Davis PT Collection. Murtagh Collection. About Search. Enable Autosuggest. You have successfully created a MyAccess Profile for alertsuccessName. Previous Chapter. Next Chapter. AMA Citation Chapter 9.
Morton D. David A. Morton, et al. The Big Picture: Gross Anatomy. Other pathologies that increase in occurrence with age include acute pancreatitis, jaundice, and gallbladder problems. Large intestinal changes such as hemorrhoids and constipation may also occur. Cancer incidence in general increases with age, including risk for rectal cancer. Privacy Policy.
Skip to main content. Search for:. Development of the Digestive System. Digestive System Development The digestive system is an endoderm-derived structure that begins developing about the fourth week of embryogenesis. Learning Objectives Outline the development of the embryonic digestive system.
Key Takeaways Key Points Around the 16th day of human development, the embryo begins to fold and the ventral surface becomes concave in two directions. Which of the following is NOT derived at least in part from the midgut?
Meckel's diverticula, vitelline cysts, or vitelline fistulas are most commonly found in association with:. Questions 8 and 9 refer to the following case: A one-week-old male infant is brought in by his parents who report bilious projectile vomiting about 2 hours after each feeding. The child has not gained much weight since birth and the parents comment that the child's diapers are not particularly soiled or when they are changed.
On physical exam the child is lethargic and exhibits signs of dehydration. The heart and breathing rates are somewhat elevated, but otherwise the heart and lungs appear normal. On physical exam, the abdomen is unremarkable. Which of the following conditions best accounts for the infant's signs and symptoms? For items 10 — 12 below, select the one lettered option from the following list that is most closely associated with each numbered item below.
Options in the list may be used once, more than once, or not at all. Simbryo Animations.
0コメント