Question

Which of the following statements about the hypothalamus is incorrect?

• A. It functions as an endocrine gland.
• B. It secretes tropic hormones that act directly on the gonads.
• C. It is subject to feedback inhibition by certain hormones.
• D. It is part of the central nervous system.

Answer 1

The correct option is B It secretes tropic hormones that act directly on the gonads.

The hypothalamus is the basal part of diencephalon, forebrain and it regulates a wide spectrum of body functions. It contains several groups of neurosecretory cells
called nuclei which produce hormones.These hormones regulate the synthesis and secretion of pituitary hormones. This control is exerted hormonally rather than by means of nerve axons, thus making the hypothalamus function as a endocrine gland. The hormones produced by hypothalamus are of two types, the releasing hormones (which stimulate secretion of pituitary hormones) and the inhibiting hormones (which inhibit secretions of pituitary hormones). The hypothalamus secretes gonadotrophins releasing hormone that stimualtes the anterior pituitary to release gonadotrophins which then regulate the activity of the gonads. The hypothalamus and the anterior pituitary gland are themselves partially controlled by the very hormones whose secretion they stimulate! In most cases this is an in inhibitory control, where the target gland hormones inhibit the secretions of the hypothalamus and anterior pituitary. This type of control system is called negative feedback inhibition and acts to maintain relatively constant levels of the target cell hormone.