Kaplan Nursing Entrance Exam Practice 2025 – Comprehensive Prep

The pineal gland is a key component of the endocrine system, which is responsible for producing hormones that regulate various bodily functions. Specifically, the pineal gland secretes melatonin, a hormone that regulates sleep-wake cycles and helps control circadian rhythms. This gland plays a crucial role in maintaining hormonal balance and influencing reproductive functions, mood regulation, and seasonal biological rhythms.

The other organs listed, while they have important functions in the body, are not primarily considered part of the endocrine system. The liver plays a major role in metabolism and detoxification but is part of the digestive system. The kidneys are essential for filtering blood and managing fluid balance in the body, belonging to the renal system. The heart, while crucial for circulating blood and transporting hormones, primarily functions as part of the cardiovascular system. Understanding the specific functions and classifications of these organs clarifies how the endocrine system operates and its vital role in overall health.