Homeostatic Mechanisms Balance the Supply and Demand OfAImostAII Nutrients
This chapter focuses on supply regulation of the major energysupplying nutrients; however, other nutrients, including vitamins and minerals, also are subject to homeostatic regulatory mechanisms.
Although many of these mechanisms directly involve the digestive system, a complete discussion is beyond the scope of this book. The homeostatic mechanisms regulating the supply of minerals and vitamins are described in select references of the Bibliography.Energy-supplying nutrients are referred to as metabolic fuels, and the physiological mechanisms for maintaining the supply of fuels and matching it to demand constitute fuel homeostasis. Fuel homeostasis is maintained by several mechanisms: the insulin-glucagon axis, the hypothalamic-pituitary axis, and the central nervous system (CNS). This chapter discusses some of the ways in which fuel is stored during the absorptive period of digestion and subsequently mobilized when needed to supply energy requirements. You may want to review Chapter 1 and the section on insulin and glucagon in Chapter 34 before reading this chapter.