Development of the digestive system Flashcards
What occurs during week one of development?
Fertilisation to implantation
What forms in week 2 of development?
Bilaminar Germ Disk
What occurs in week 3 of development?
Trilaminar Germ Disc forms
What occurs in weeks 3-8 of development?
Organogenesis
What is the first phase of embryonic development?
Growth phase - cells divide
What is the second phase of embryonic development?
Morphogenesis - development of shape, size of organs
What is the third phase of embryonic development ?
Differentiation - Maturation of physiological processes
What does the ectoderm form?
Skin, CNS, PNS, liver, eyes, nose, ears
What does the endoderm form?
Epithelial lining of resp. system, GIT, Liver,pancreas, thyroid, bladder etc
What does the mesoderm?
Muscle, bones, cartilage, dermis, vascular system, urogenital system, spleen etc
The lateral plate mesoderm gives rise to what?
Parietal and visceral mesoderm
Where does the foregut arise from?
The cranial part of the primitive gut tube
What divides the foregut into trachea and oesophagus?
Tracheo-oesophageal septum
When does the foregut dilate to form the stomach?
Week 4
How is the stomach attached to the dorsal and ventral wall?
Via a mesentery called the mesogastrium
How is the duodenum formed?
From the caudal part of the foregut and the cranial part of the midgut
What supplies the duodenum?
The coeliac trunk and the superior mesenteric artery
When does the liver bud appear?
Third week
When does the spleen form
END OF WEEK 4/ START OF WEEK 5
What occurs if the tracheo-oesophageal septum deviates incorrectly?
Atresia and tracheo-oesophageal fistula
What occurs if the ventral bud fails to deviate around the duodenum correctly?
Annular pancreas which may result in duodenal stenosis
What does the midgut form?
The distal part of the duodenum, jejunum, ileium, caecum, appendix, ascending colon and proximal 2/3 of transverse colon
What does the cephalic part of the primary intestinal loop form?
The distal duodenum, jejunum and the proximal ileum
What does the caudal part of the distal ileum become?
Distal ileum, appendix, ascending colon and proximal 2/3 of the transverse colon
When does midgut rotation occur?
Week 6
What is omphalocele and how does it occur?
The herniation of abdominal viscera through an enlarged umbilical ring as a result of the failure of retraction of umblilical ring
What happens if there are remnants of the vitelline duct?
Meckels diverticulum which may form fistula or cyst
What does the hindgut form?
Distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum and upper part of anal canal
What does the endoderm of the hindgut form?
the lining of the bladder and urethra
What supplies the hindgut?
The inferior mesenteric artery
When does the liver form?
Week 3
What is gastrochisis?
Herniation of abdo viscera. No amnion covering viscera
What layer makes the spleen?
Mesoderm
When does midgut rotation occur?
Week 6
