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.
Wildebeest at the Ngorongoro Crater; an example of a herd in the wild. A herd is a social grouping of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is referred to as herding. The term herd is generally applied to mammals, and most particularly to the grazing ungulates that classically display this behaviour.