Hormone- chemical messenger that travels in the blood
Endocrine gland- specialized organ ( anterior pituitary, pineal gland, thyroid, and parathyroid)
Endocrine tissue and cells- group of endocrine cells in EI tract (placenta, thymus, gonads, hypothalamus, heart)
Target cell- cells that bind to hormones and may be changed by that hormone. Also has a specific receptor cell