An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk.
Glands
Examples of exocrine glands include sweat glands, lacrimal glands, salivary glands, etc.
Exocrine
The endocrine system is made up of the endocrine glands that secrete hormones.
Endocrine
Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs
Hormones
Cell surface receptors are receptors that are embedded in the plasma membrane of cells. They act in cell signaling by receiving extracellular molecules.
cell receptors
A target cell responds to a hormone because it bears receptors for the hormone.