Gland
Pancreatic islets (of Langerhans)
Vascular endocrine clusters within the pancreas
High-yield
Human islet vessels integrate with surrounding pancreatic microcirculation. A universal one-way beta-core → mantle → acinar flow scheme is too simple.
Overview
Islets form a small endocrine portion of the pancreas among its exocrine acini. Cell composition, size and distribution vary, with extensive capillary contact and local signaling between endocrine types. Their coordinated secretion balances nutrient storage with fuel mobilization.
Reference facts
- Location
- Scattered through pancreatic parenchyma with regional variation; endocrine tissue is often more concentrated toward the tail, while PP-cell-rich tissue is prominent in the ventral-derived head region.
- Hormones
- Beta cells release insulin, alpha cells glucagon, delta cells somatostatin and PP cells pancreatic polypeptide; rare epsilon cells express ghrelin.
- Blood supply
- Supplied by branches of splenic and pancreaticoduodenal vessels through a dense integrated capillary network with variable inlet and outlet patterns.
- Innervation
- Vagal, sympathetic, vascular and local paracrine mechanisms interact to regulate endocrine secretion.
- Function
- Coordinates glucose and other nutrient metabolism through hormones with complementary and feedback-linked effects.
Clinical correlation
Type 1 diabetes principally destroys beta cells but also disrupts broader islet function. Type 2 diabetes combines insulin resistance with inadequate beta-cell compensation. Pancreatic neuroendocrine tumors may be nonfunctioning or produce hormone-excess syndromes.
Frequently asked questions
Where are the pancreatic islets (of Langerhans) located?
Scattered through pancreatic parenchyma with regional variation; endocrine tissue is often more concentrated toward the tail, while PP-cell-rich tissue is prominent in the ventral-derived head region.
What do the pancreatic islets (of Langerhans) secrete?
Beta cells release insulin, alpha cells glucagon, delta cells somatostatin and PP cells pancreatic polypeptide; rare epsilon cells express ghrelin.
What do the pancreatic islets (of Langerhans) do?
Coordinates glucose and other nutrient metabolism through hormones with complementary and feedback-linked effects.
What is the blood supply of the pancreatic islets (of Langerhans)?
Supplied by branches of splenic and pancreaticoduodenal vessels through a dense integrated capillary network with variable inlet and outlet patterns.