Certified Professional Coder (CPC) Practice Test 2025 - Free CPC Practice Questions and Study Guide

The adrenal gland is classified as an endocrine gland because it produces and secretes hormones directly into the bloodstream. Unlike exocrine glands, which release their secretions through ducts to specific locations (like the salivary glands that release saliva into the oral cavity), endocrine glands are ductless and have a systemic effect by releasing hormones that circulate throughout the body. The adrenal glands, located on top of the kidneys, play a crucial role in regulating metabolism, immune response, blood pressure, and stress response through hormones like cortisol and adrenaline.

The thymus gland, while also an endocrine organ, primarily functions in immune system development during childhood rather than hormone production in adulthood. Salivary glands fall under the category of exocrine glands due to their ducted secretion of saliva. The term "exocrine" itself refers to glands that release secretions through ducts, differentiating them from endocrine glands like the adrenal gland. Therefore, in this context, the adrenal gland is the most fitting example of an endocrine gland based on its structure and function.