Designing the Chassis: Muscles

Revisit your journal entry that you wrote for the warm-up activity. Have your ideas about muscles changed? The muscular system is an amazing structure of the body. Without muscles, your body would not work. All body functions depend upon muscles. The heart has its own special muscle type called cardiac, and organs such as the stomach and intestines have smooth muscle to coordinate body functions. There is even skeletal muscle to produce movement.

Movement occurs around joints or intersections of two or more bones. Joints come in all shapes and sizes, depending on the type of motion that needs to occur. The hip and shoulder joint need the most movement, so they have ball-and-socket-style joints. These joints allow the arms and legs to adduct, abduct, flex, extend, and rotate. The spinal column is made to pivot from side-to-side, while a wrist joint is ellipsoidal, or allowed to move in all directions except pivot. There are also hinge joints which function like those of a door, with flexion and extension and little or no sideways movement.