| Term | Definition |
| adrenal cortex | the outer portion of the adrenal gland |
| adrenal medulla | the inner portion of the adrenal gland |
| anterior pituitary | the front lobe of the pituitary gland |
| hormone | a substance that an endocrine gland secretes and that the blood or bodily fluids transport |
| negative feedback system | a mechanism activated by an imbalance that corrects it |
| pancreas | glandular organ in the abdominal cavity that secretes hormones and digestive enzymes |
| parathyroid gland | one of four small endocrine glands embedded in the posterior portion of the thyroid gland |
| pineal gland | a small structure located in the central part of the brain that secretes the hormone melatonin, which controls certain biological rhythms |
| posterior pituitary | the lobe of the pituitary gland that secretes oxytocin and antidiuretic hormone |
| prostaglandin | a compound with powerful, hormonelike efffects |
| target cell | a specific cell on which a hormone exerts its effect |
| thymus gland | a glandular organ in the mediastinum behind the sternum and between the lungs |
| thyroid gland | endocrine gland located just below the larynx and in front of the trachea that secretes thyroid hormones |