Review of Medical Physiology - William F. Ganong 2002

Endocrine System, Metabolism, and Reproduction
Energy Balance, Metabolism, and Nutrition
Introduction

Like The Nervous system, the Endocrine System coordinates the activities of various body systems, adapting them to Changes in the external and internal environment. Endocrine integration is achieved through Hormones—chemical messengers produced by ductless glands and transported by the Blood to target Cells. Other types of chemical messengers are described in Chapter 1. Some hormones are amines, whereas others are Amino Acids, Polypeptides, Proteins, or Steroids.

Hormones regulate metabolic processes. The term METABOLISM, which literally means change, is used to describe all the chemical and energy transformations that occur within the body.

In animal Tissues, CARBOHYDRATES, proteins, and fats undergo oxidation, primarily producing CO₂ and H₂O, while releasing the energy essential for life. Carbon dioxide, Water, and energy are also generated when nutrients are burned outside the body. However, within the living Organism, oxidation is not a single-step, semi-explosive reaction; rather, it is a complex, stepwise process known as Catabolism, during which energy is released in small, usable increments. This energy can be stored in the body in the form of high-energy phosphate compounds, as well as proteins, fats, and complex carbohydrates synthesized from simpler molecules. The energy-requiring formation of these compounds is called anabolism. This chapter examines the core concepts necessary for understanding The impact of the endocrine system on energy release and utilization, as well as on the metabolism of carbohydrates, proteins, and fats.