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.
a low testosterone level or sperm count, or both. sex hormone : a hormone that affects and is made by the reproductive (sex) organs. It is responsible for secondary sex traits, such as facial hair in men.estosterone is the main sex hormone that men have. It controls male physical features. The testes (testicles) make testosterone. Women have testosterone too, but in much smaller amounts than in men.