Voluntary muscles are muscles of the skeletal body that connect to bones. They control the movement of the head, limbs, the neck and other body parts, under conscious control. The muscles of the skeleton are coordinated by nerve signals coming from the brain, which communicate with muscle fibers in each muscle and cause them to contract.
The male reproductive system includes a number of hormones and organs that are involved in reproduction. These hormones and organs can be found either inside or outside of the pelvis.
Reproduction refers to the process where organisms create more of themselves. However, although the reproductive system is vital to maintaining a species' existence, unlike other body systems it is not essential for keeping an individual alive.