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.
1 The testes are responsible for making testosterone, the primary male sex hormone, and for generating sperm. 2  Within the testes are coiled masses of tubes called seminiferous tubules.3  These tubes are responsible for producing sperm cells. Most men have two testes. 2  The testes are responsible for making testosterone, the primary male sex hormone, and for generating sperm. 3  Within the testes are coiled masses of tubes called seminiferous tubules.