The thyroid gland is located on the front surface of the trachea.  It has two lobes, and it produces two hormones:  Triiodothyronine (T3) and Thyroxine (T4).  Both T3 and T4 have the same effect on the target cell, but T3 is usually most active.  The thyroid also regulates metabolism.  The thyroidal secretions are controlled by both the hypothalamus and the pituitary.

     The pancreas secretes insulin, a hormone that regulates glucose in take of the cells.  A deficiency in this hormone results in diabetes mellitus.  Insulin regulates the blood sugar levels by stimulating cells to take in glucose.  It also stimulates the synthesis of protein and fat storage.

     The adrenal medulla is the gland behind the fight-or-flight reaction.  It secretes two hormones:  epinephrine and norepinephrine. (Epinephrine is also known as adrenaline.)  Epinephrine secretion is triggered by stress, both positive and negative stress.  It increases the rate and the stroke volume of the heart.

     The testis and ovaries secrete hormones that are grouped into three major categories: androgens, estrogens, and progestins.  All three are found in both males and females, but each in varying amounts. 

     Androgens are primarily produces by the testis.  Testosterone is the primary hormone in this group.  Androgens stimulate the maintenance and development of the male reproductive system.

     Estrogens are the female equivalent of Androgens.  They maintain the female reproductive system and trigger the development of female second sex characteristics.  Progestins maintain and prepare the uterus for growth and development of an embryo.