Which of the following statements concerning the endocrine system is NOT true?

• A. Endocrine glands secrete hormones directly into the bloodstream.
• B. Hormones released by the endocrine system typically have rapid, short-lived effects.
• C. The pancreas functions as both an endocrine and exocrine gland.
• D. The pituitary gland is often referred to as the 'master gland' of the endocrine system.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the role of the endocrine system. The endocrine system is responsible for producing and releasing hormones into the bloodstream to regulate various physiological processes, such as growth, metabolism, and reproduction.
2. Step 2: Analyze the first statement: 'Endocrine glands secrete hormones directly into the bloodstream.' This is true because endocrine glands, unlike exocrine glands, release hormones directly into the circulatory system without using ducts.
3. Step 3: Analyze the second statement: 'Hormones released by the endocrine system typically have rapid, short-lived effects.' This is not true. Hormones released by the endocrine system generally have slower, long-lasting effects compared to the nervous system, which is responsible for rapid, short-lived responses.
4. Step 4: Analyze the third statement: 'The pancreas functions as both an endocrine and exocrine gland.' This is true. The pancreas has an endocrine function (secreting insulin and glucagon into the bloodstream) and an exocrine function (releasing digestive enzymes into the small intestine).
5. Step 5: Analyze the fourth statement: 'The pituitary gland is often referred to as the 'master gland' of the endocrine system.' This is true because the pituitary gland regulates many other endocrine glands by releasing hormones that control their activity.