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.
Herding can be performed by people or trained animals such as herding dogs that control the movement of livestock under the direction of a person. The people whose occupation it is to herd or control animals often have herd added to the name of the animal they are herding to describe their occupation (shepherd, goatherd, cowherd).