Question 1
Which of the following is not an endocrine gland?
- Mammary gland
- Hypothalamus
- Pituitary
- Adrenal gland
Explanation: Endocrine glands secrete hormones into the blood stream, lined with endothelium, allowing them to travel through the blood and to act at a distant site. Exocrine organs, in contrast, secrete products into lumens that are lined with epithelium.
Mammary glands are used in lactation. Because the milk is not secreted into the blood, the mammary glands are not endocrine glands.
The hypothalamus releases hormones into the blood, such as corticotropin-releasing hormone (CRH). The pituitary releases hormones such as prolactin. The adrenal gland secretes hormones such as cortisol.