The islets of Langerhans make up just 1 to 2% of pancreatic mass yet hold the reins on blood sugar. After a meal the beta cells at the islet centre release insulin to pull glucose back into the 70 to 140 mg/dL band; during exercise it falls instead and the alpha cells at the rim answer with glucagon. In type 1 diabetes the beta cells go nearly silent; in type 2 insulin still pours out, but resistant tissue makes the fall painfully slow.
The islets of Langerhans make up just 1 to 2% of pancreatic mass yet hold the reins on blood sugar. After a meal the beta cells at the islet centre release insulin to pull glucose back into the 70 to 140 mg/dL band; during exercise it falls instead and the alpha cells at the rim answer with glucagon. In type 1 diabetes the beta cells go nearly silent; in type 2 insulin still pours out, but resistant tissue makes the fall painfully slow.
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