BackChapter 16: The Endocrine System – Human Anatomy & Physiology Study Notes
Study Guide - Smart Notes
Tailored notes based on your materials, expanded with key definitions, examples, and context.
Endocrine System Overview
Introduction to the Endocrine System
The endocrine system is one of the two major control systems of the body, working alongside the nervous system to maintain homeostasis. It influences metabolic activities through hormones transported in the blood, producing responses that are slower but longer-lasting than those of the nervous system.
Endocrinology: The study of hormones and endocrine organs.
Main functions:
Reproduction
Growth and development
Maintenance of electrolyte, water, and nutrient balance of blood
Regulation of cellular metabolism and energy balance
Mobilization of body defenses
Comparison of Nervous and Endocrine Systems
Functional Differences
The nervous and endocrine systems both regulate body functions, but they differ in their mechanisms and effects.
Nervous System | Endocrine System |
|---|---|
Initiates responses rapidly | Initiates responses slowly |
Short-duration responses | Long-duration responses |
Acts via action potentials and neurotransmitters | Acts via hormones released into the blood |
Acts at specific locations determined by axon pathways | Acts at diffuse locations—targets can be anywhere blood reaches |
Neurotransmitters act over short distances | Hormones act over long distances |
Signal strength coded by frequency of action potentials | Signal strength coded by concentration of hormone |
Major Topics in the Endocrine System
Chapter Structure
This chapter covers the following key areas of the endocrine system:
16.1: The endocrine system as a major control system
16.2: Hormone structure
16.3: Mechanisms of hormone action
16.4: Stimuli causing hormone release
16.5: Determinants of cell responses to hormones
16.6: The hypothalamus and its control of the pituitary gland
16.7: The thyroid gland
16.8: The parathyroid glands
16.9: The adrenal glands
16.10: The pineal gland
16.11: Organs with other major functions that also secrete hormones
Developmental Aspects: Environmental effects and changes throughout life
Key Terms and Concepts
Hormone: A chemical messenger secreted by endocrine glands, transported by blood to target organs.
Endocrine gland: Ductless gland that releases hormones directly into the bloodstream.
Homeostasis: The maintenance of a stable internal environment.
Target cell: A cell that has receptors for a specific hormone.
Example: Hormonal Regulation of Growth
Growth hormone (GH) is secreted by the anterior pituitary gland and stimulates growth and metabolism in target tissues. Its release is regulated by hypothalamic hormones and feedback mechanisms.
GH stimulates:
Cellular uptake of nutrients
Protein synthesis
Bone and muscle growth
Summary Table: Endocrine System Functions
Function | Example Hormone | Target Tissue |
|---|---|---|
Growth and development | Growth hormone (GH) | Bone, muscle |
Metabolism regulation | Thyroid hormone (TH) | Most body cells |
Electrolyte balance | Aldosterone | Kidneys |
Stress response | Cortisol | Various tissues |
Additional info: These notes are based on the introductory slides and chapter outline for "Chapter 16: The Endocrine System" from Marieb Human Anatomy & Physiology. For detailed mechanisms, hormone pathways, and clinical correlations, refer to the full chapter content.
