The Skeleton System is the framework of the human anatomy, supporting the body and protecting its internal organs. Two hundred and six bones compose the skeleton, about half of which are in the hands and feet. Most of the bones are connected to other bones at flexible joints, which lend the framework a high degree of flexibility. The skeletons of male and female bodies are essentially the same, with the exceptions being that female bones are usually lighter and thinner than male bones, and the female pelvis is shallower and wider than the male's. This latter difference makes childbirth easier.
Muscular System: The human body contains more than 650 individual muscles anchored to the skeleton, which provide pulling power so that you can move around. These muscles constitute about 40% of your total body weight. The muscle's points of attachment to bones or other muscles are designated as origin or insertion. The point of origin is the point of attachment to the bone to which the muscle is anchored. The point of insertion is the point of attachment to the bone the muscle moves. Generally, the muscles are attached by tough fibrous structures called tendons. These attachments bridge one or more joints and the result of muscle contraction is movement of these joints. Primarily muscle groups move the body, not by individual muscles. These groups of muscles power all actions ranging from the threading of a needle to the lifting of heavy weights.
The Nervous System of the human anatomy is responsible for sending, receiving, and processing nerve impulses. All of the body's muscles and organs rely upon these nerve impulses to function. Three systems work together to carry out the mission of the nervous system: the central, the peripheral, and the autonomic nervous systems. The central nervous system is responsible for issuing nerve impulses and analyzing sensory data, and includes the brain and spinal cord. The peripheral nervous system is responsible for carrying nerve impulses to and from the body's many structures, and includes the many crania spinal nerves, which branch off of the brain and spinal cord. The autonomic nervous system is composed of the sympathetic and parasympathetic systems and is responsible for regulating and coordinating the functions of vital structures in the body.