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.
In women, the adrenal glands and ovaries produce small amounts of testosterone. Before a boy is even born, testosterone is working to form male genitals. During puberty, testosterone is responsible for the development of male attributes like a deeper voice, beard, and body hair.