Zoology 9th Edition by Stephen Miller

Exercise 1

In addition to a nervous system, animals also need an endocrine system for maintaining homeostasis. Whereas the nervous system reacts quickly to disturbances of function, the endocrine system works for long-term regulation of disturbances by producing hormones. Hormones coordinate the activity of specific target cells. Examples include metabolism, respiration, excretion, movement, and reproduction. Chemical messengers can be categorized as follows: local chemical messengers (autocrine or paracrine agents), neurotransmitters, neuropeptides, hormones, and pheromones.
How do hormones and neurotransmitters differ?