The arm is not part of a single system; to construct an arm you need lots of systems, which includes the muscular, skeletal, circulatory, nervous, and integumentary systems.
the arm
arm
They belong to the peripheral nervous system, as opposed to the central nervous system (as they are to be found on the periphery of the body).
They belong to the peripheral nervous system, as opposed to the central nervous system (as they are to be found on the periphery of the body).
your nervous system sends messages to the brain like when you move your arm you nervous system sends the message to the brain
The joints connects the arm to the upper body.
While basically any organ in your body has a function (aside perhaps of the appendix) the only "organ" in your arm that you could have removed without losing arm functions would be a lymphic node, which is part of your immune system. Losing one of these nodes would lower the effectiveness of your immune system, but not cost you arm function.
Your arm
Lifting your arm away from your body is abduction
The average human body height to arm span ratio is approximately one to one. The arm to body ratio in a human is two to one.
Skeletal system
The Orion arm