Chapter 42, Problem 15TYK

Summary Introduction

To review:

The endocrine system that evolved earlier, endocrine glands or neurosecretory neurons.

Introduction:

The endocrine system can be defined as the system that is composed of chemical messengers known as hormones and glands. The endocrine system consists of groups of glands that secrete hormones in the bloodstream. These hormones regulate the functions of the target sites. The activity of these hormones is regulated by a feedback mechanism.