HOMEOSTASIS

Concentration Control

Concentration Control

Instead of being controlled by the central nervous system (CNS), blood glucose is controlled by the pancreas. Islets of Langerhans, located in the pancreas, act as glucose receptors and endocrine cells and control the levels of glucose by releasing hormones. They’re comprised of two types of cell: ? and ? cells. Both types are comprised of glucose receptors. The difference is:

  • ? cells secrete glucagon in response to a low blood glucose concentration
  • ? cells secrete insulin in response to a high blood glucose concentration

Glucagon and insulin are antagonistic hormones because of their opposite effects on blood glucose.

The blood glucose concentration is controlled like this:

The blood glucose level increases (for example, after a meal)??-cells located in the pancreas detect this increase and insulin is secreted?

More glucose is taken up by the cells, glycogenesis increases in the liver and the muscle, and lipogenesis increases in the liver

?

Glucose is removed from the blood

Normal blood glucose concentration

? ?

? ?

Normal blood glucose concentration

The blood glucose level drops (for example, too much glucose is removed from the blood)??-cells located in the pancreas detect this drop and glucagon is secreted?

Glycogenolysis and gluconeogenesis increases in the liver

?

Glucose is released into the blood