Sources of hormones in humans = the endocrine system [Fig. 37.2] 3. Target cells = cells with receptors for a given chemical messenger that can alter their activities in response to messenger.- Hormones are transported throughout the body by the blood, but they only elicit responses in target cells.. Do not diffuse into cells. b. Target cells have specific receptor for hormone on cell surface. c. Hormone binds to receptor and causes a second messenger to be released within the cell.
Definition of herder. : one that herds; specifically : a person who manages, breeds, or tends to livestock : herdsman 1.
A herding dog, also known as a stock dog or working dog, is a type of pastoral dog that either has been trained in herding or belongs to breeds developed for herding. Their ability to be trained to act on the sound of a whistle or word of command is renowned throughout the world. Collies are recommended as herding dogs.