There are three types of muscle:

-Skeletal Muscle: multiple nuclei, striarated, voluntary movement 
-Smooth Muscle: one nucleus, spindle shaped, involved in digestion

-Cardiac Muscle: one or two nuclei, striarated, heart muscle

Tendons connect muscles to bones. Muscles are used to contract which allows them to move parts of the body. By sending a signal to a neuromuscular junction that connects to a muscle fiber. Each muscle fiber has fibers within fibers and each individual section of the fibers contract. Each segment of a muscle fiber has thin filament called Actin and a thick filament called Myosin. The Myosin pulls the Actin, which is anchored to the cell which then make the entire cell smaller. Myosin heads recievie ATP which causes them to pull the actin closer. By doing this to thousands of cells muscles can move. 

 

One genetic disorder related to the Muscle System is Muscular Distrophy, which is a genetic mutation that causes muscles to breakdown and deteriorate. It destroys the membrane covering the muscle fiber which leads to the breakdown of muscle tissue.

 

Another genetic disorder regarding the Muscle System are Mitochodrial Myopathies, which is a genetic mutation in the mitochodria. This leads to an underproduction of ATP and muscle deterioration.