Germ%20layers:%20Cell%20lineages

1
Germ layers Cell lineages
2
Epithelium and Mesenchyme

• Defined by cell morphology and expression of
  definitive markers

Mesenchyme
Loosely packed connective tissue - migratory
3
Pancreas Development
Cardiac mesoderm signals
Notochord signals
Endoderm
Ventral pancreas
Dorsal pancreas
Signals from pancreatic mesenchyme
Signals from pancreatic mesenchyme
Exocrine cells Endocrine islets Ductal cells
(Low replication and regeneration potential)
4
Cellular Organization of the (Mouse) Pancreatic
Islet
Insulin (? cells)
Glucagon (? cells)
Somatostatin (d cells)
Pancreatic Polypeptide (PP)
Ghrelin (e cells)

• Human pancreas has characteristic shape, but
  with islet cell types intermingled

5
Liver Development
Cardiac mesoderm signals
Liver (2 lobes)
Endoderm
Signals from at least 3 different mesodermal
tissues and endothelial cells
Hepatocytes
High replication potential