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.
For example, men tend to be taller than women, but there are many people of both sexes who are in the mid-height range for the species. Some examples of male secondary sexual characteristics in humans, those acquired as boys become men or even later in life, are: 1  more pubic hair. 2  more facial hair.he term manhood is used to describe the period in a human male's life after he has transitioned from boyhood, having passed through puberty, usually having attained male secondary sexual characteristics, and symbolises a male's coming of age. The word man is used to mean any adult male.