Talk:Endocrine - Pancreas Development

Introduction

Pancreas adult

pancreas structure

Lecture- Gastrointestinal Tract Development | UNSW Embryology - Pancreas Development see also GIT Notes- Pancreas

• Functions - exocrine (amylase, alpha-fetoprotein), 99% by volume; endocrine (pancreatic islets) 1% by volume
• Exocrine function - begins after birth
• Endocrine function - from 10 to 15 weeks onward hormone release
  • exact roles of hormones in regulating fetal growth?

Pancreas Development

Pancreatic buds and duct developing

Stage22 pancreas

• Pancreatic buds - duodenal level endoderm, splanchnic mesoderm forms dorsal and ventral mesentery, dorsal bud (larger, first), ventral bud (smaller, later)
• Pancreas Endoderm - pancreas may be opposite of liver
  • Heart cells promote/notochord prevents liver formation
  • Notochord may promote pancreas formation
  • Heart may block pancreas formation

• Duodenum growth/rotation - brings ventral and dorsal buds together, fusion of buds
• Pancreatic duct - ventral bud duct and distal part of dorsal bud, exocrine function
• Islet cells - cords of endodermal cells form ducts, from which cells bud off to form islets

Pancreatic Islets

• Islets of Langerhans - 4 endocrine cell types
• Alpha - glucagon, mobilizes lipid
• Beta - insulin, increase glucose uptake
  • Beta cells, stimulate fetal growth, continue to proliferate to postnatal, in infancy most abundant
• Delta - somatostatin, inhibits glucagon, insulin secretion
• F-cells - pancreatic polypeptide

Pancreas Timeline

• Week 7 to 20 - pancreatic hormones secretion increases, small amount maternal insulin
• Week 10 - glucagon (alpha) differentiate first, somatostatin (delta), insulin (beta) cells differentiate, insulin secretion begins
• Week 15 - glucagon detectable in fetal plasma