Learning Objectives By the end of this section, you will be able to: A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx (Figure 17.12). The medial region, called the isthmus, is flanked by wing-shaped…
Learning Objectives By the end of this section, you will be able to: The hypothalamus–pituitary complex can be thought of as the “command center” of the endocrine system. This complex secretes several hormones that directly produce responses in target tissues,…
Learning Objectives By the end of this section, you will be able to: Although a given hormone may travel throughout the body in the bloodstream, it will affect the activity only of its target cells; that is, cells with receptors…
Learning Objectives By the end of this section, you will be able to: Communication is a process in which a sender transmits signals to one or more receivers to control and coordinate actions. In the human body, two major organ…
Figure 17.1 A Child Catches a Falling Leaf Hormones of the endocrine system coordinate and control growth, metabolism, temperature regulation, the stress response, reproduction, and many other functions. (credit: “seenthroughmylense”) CHAPTER OBJECTIVES After studying this chapter, you will be able to: You may…
Divisions of the Autonomic Nervous System The primary responsibilities of the autonomic nervous system are to regulate homeostatic mechanisms in the body, which is also part of what the endocrine system does. The key to understanding the autonomic system is…
By the end of this section, you will be able to: An important way to understand the effects of native neurochemicals in the autonomic system is in considering the effects of pharmaceutical drugs. This can be considered in terms of…
Learning Objectives By the end of this section, you will be able to: The pupillary light reflex (Figure 15.10) begins when light hits the retina and causes a signal to travel along the optic nerve. This is visual sensation, because…
Learning Objectives By the end of this section, you will be able to: The autonomic nervous system regulates organ systems through circuits that resemble the reflexes described in the somatic nervous system. The main difference between the somatic and autonomic…
Learning Objectives By the end of this section, you will be able to: The nervous system can be divided into two functional parts: the somatic nervous system and the autonomic nervous system. The major differences between the two systems are…