The muscular system is the part of the human body that helps a person to move around and function correctly. Many muscles that are part of the anatomy of this system are attached to the bones of the skeletal system and contract relatively easily. These groups of fibers include the biceps in the arms and the muscles located in the thighs, along with muscles in the neck and chest. An individual has control over them, so they are considered to be voluntary. Meanwhile, other fibers that form the heart and the insides of organs are involuntary, as a person does not dictate their movements.
Biceps make up part of the anatomy of the muscular system. These muscles are located in the top part of a person’s arms and are connected to his or her shoulder blades. In addition, they stretch along the bone of the top section of a person’s arm, going down to the individual’s elbow. The biceps, which essentially have two heads, enable a human being to retract his or her arm and thus are considered voluntary muscles that are extremely important for transporting physical items.
Several fibers make up a person’s bottom area as well. For instance, the adductor longus muscle is triangular in shape and goes from a bone that is part of the base on which the upper body rests all the way down to the thigh bone. This type of voluntary muscle helps to move the thigh inward and enables the hip to rotate, so it is a significant part of the anatomy of the muscular system. The abductor muscles in the buttocks area of the body further enable a person to move his or her legs outward to the side, as someone would do when performing jumping-jack exercises.
A major part of the human body also includes the tissues that make up the neck. The voluntary neck muscle, also called the sternocleidomastoid muscle, is located on the side of the neck and goes behind the ear. This aspect of the anatomy of the muscular system helps someone to turn his or head from side to side or to bend his or head down toward the chest.
Another important part of this physical body system is the chest muscle. Also called the pectoralis major, this voluntary muscle starts at the breastbone and ribs and goes all the way up to the collarbone, and additionally stretches to the bone in a person’s upper arm. As part of the anatomy of the muscular system, this muscle enables the arms to move across the body, while the pectoralis minor muscle located below it enables the shoulder blade to move.
The heart muscle is a collection of fibers that attach together and are involuntary. This means that, unlike other muscles, a human being does not control the movement of this muscle. Likewise, the smooth muscles that make up organs such as the arteries or gallbladder operate under the control of the nervous system rather than by the conscious movement of an individual.