Lesson 1, Topic 1
In Progress

Neuroendocrine System

April 11, 2024

Learning Objective: Examine the connection between the endocrine and nervous systems.
The endocrine system is composed of ductless glands throughout the body. Endocrine glands release hormones directly into the bloodstream, and the blood transports them to target cells. The hormones act as messengers to the target cells, telling the cells to alter their functions to help maintain homeostasis in the body. Hormones function as the body’s chemical messengers, transferring information from one group of cells to another. They control metabolism, growth, mood, sexual maturity, reproduction, and water and electrolyte balance. Hormone levels vary and can be affected by outside factors, such as illness and stress. FIGURE 24.1 shows the endocrine glands and their locations.


Maintaining Homeostasis
Learning Objective: Describe how the neuroendocrine system maintains homeostasis.
      The nervous system and the endocrine system can work alone or together. Working jointly, as a neuroendocrine system, they perform communication functions and maintain homeostasis. The brain sends out signals to and continually receives feedback from the endocrine system. The nervous system communicates quickly through nerve impulses and delivers rapid responses to maintain homeostasis. The endocrine system communicates slowly through hormones, which maintain homeostasis for a longer period of time. The body needs both systems working together through communication to maintain homeostasis.


Hypothalamus
Learning Objective: Discuss the function of the hypothalamus.
      The hypothalamus, located in the middle of the brain, is the major connection for the neuroendocrine system. It plays an important role in controlling the endocrine system. When the hypothalamus detects rising levels of a target organ’s hormones, it sends a signal to the pituitary gland to release or prevent pituitary hormone production.

FIGURE 24.1  Location of the endocrine glands. From Patton KT, Thibodeau GA: Anatomy and physiology, ed 9, St. Louis, 2016, Mosby.

      The hypothalamus is also responsible for the production of antidiuretic hormone (ADH) and oxytocin. These two hormones are produced by the hypothalamus and stored and secreted by the posterior lobe of the pituitary gland. They will be discussed in more detail in the next section.