Final answer:
The muscular system includes cardiac, smooth, and skeletal muscles responsible for various body functions such as movement, circulation, and digestion. It allows for voluntary and involuntary movements by contracting muscle fibers, which either pull on bones for movement or exert pressure internally.
Step-by-step explanation:
The muscular system comprises all the muscles in the body and is essential for various bodily functions, including movement, circulation, and digestion. It consists of three types of muscles: cardiac, smooth, and skeletal. Cardiac muscle is found in the heart and is responsible for pumping blood throughout the body. Smooth muscle is found in the walls of internal organs and helps to move substances through the body. Skeletal muscles are connected to bones and are responsible for voluntary movements such as standing, walking, and running.
Muscle contractions in the muscular system allow us to not only move our limbs and trunk but also support the body in various activities, such as yoga. These contractions work by muscle fibers shortening to pull on bones or exert pressure within the body. Voluntary movements are those we consciously control, while involuntary muscle contractions occur automatically, such as the beating of the heart.
Understanding the muscular system is crucial as it plays a vital role in our everyday life, keeping us active and alive. It works in tandem with the skeletal system to provide support and mobility, making activities as diverse as running and grasping items possible.