Which statement best describes endocrine glands?

Which statement best describes endocrine glands?

• A. Endocrine glands are glands that secrete hormones directly into the bloodstream
• B. Nerve cells transmit hormones
• C. Exocrine glands secrete hormones into ducts
• D. Bones store minerals

Answer: (A)

Endocrine glands are defined by releasing hormones directly into the bloodstream, allowing these chemical messengers to travel to distant organs and regulate important processes. This circulating route is what sets endocrine glands apart from exocrine glands, which dump their products into ducts that lead to body surfaces or cavities (like saliva into the mouth or sweat onto the skin). Nerve cells, on the other hand, transmit signals via electrical impulses and neurotransmitters within the nervous system, not through circulating hormones. Bones store minerals such as calcium and phosphate, rather than secreting hormones. So, secreting hormones directly into the bloodstream is the defining feature of endocrine glands.

Endocrine glands are defined by releasing hormones directly into the bloodstream, allowing these chemical messengers to travel to distant organs and regulate important processes. This circulating route is what sets endocrine glands apart from exocrine glands, which dump their products into ducts that lead to body surfaces or cavities (like saliva into the mouth or sweat onto the skin). Nerve cells, on the other hand, transmit signals via electrical impulses and neurotransmitters within the nervous system, not through circulating hormones. Bones store minerals such as calcium and phosphate, rather than secreting hormones.

So, secreting hormones directly into the bloodstream is the defining feature of endocrine glands.