The same chemical messenger may be either a hormone or a neurotransmitter, depending on its source and mode of delivery to the target tissue.

Question

Quizplus · Accepted Answer

This statement is true. A chemical messenger can act as a hormone if it is secreted by an endocrine gland into the bloodstream to act on distant target tissues, or it can act as a neurotransmitter if it is released by a nerve cell to act on adjacent target cells. Examples of chemical messengers that can act as both hormones and neurotransmitters include adrenaline and dopamine.

The Same Chemical Messenger May Be Either a Hormone or a Neurotransmitter