Upper Arm Muscle - Bicep Muscle Anatomy. There are three major muscle groups in the arm. The biceps brachii is a two headed muscle with point of origin under the deltoid and point of insertion just below the elbow. The basic function of your biceps is to lift and curl the arm, and to also pronate (twist downward) the wrist.
Testosterone is primarily responsible for the development of male secondary sexual characteristics, e.g., beard growth, pubic hair growth, deepening of voice, etc. Testosteron â¦ e.
Testosterone Replacement Therapy. Testosterone is a major sex hormone produced in the testes of men. The pituitary gland is responsible for controlling the production of testosterone hormone. In the testes, luteinizing hormone binds to receptors on Leydig cells; this stimulates production and secretion of testosterone. Testosterone helps to develop the primary and secondary sexual characteristics in males.