Presentation on theme: "The Muscular System. How many muscles do you have in the body? Approximately 640 muscles! Muscles make up approximately 40% of your body weight."— Presentation transcript:
The Muscular System
How many muscles do you have in the body? Approximately 640 muscles! Muscles make up approximately 40% of your body weight
Types of Muscles Voluntary muscles – muscles you can control by will or thinking What is an example? Involuntary muscles – muscles you cannot control at will, but work automatically What is an example?
Different Kinds of Muscles 1. Skeletal muscle (voluntary) 2. Smooth (involuntary) 3. Cardiac (involuntary)
Skeletal Striated muscles Holds the skeleton together Gives the body shape Helps with everyday movements
Smooth Controlled by nervous system automatically Examples of smooth muscles are the walls of the stomach and intestines, which help break up food and move it through the digestive system. Smooth muscle is also found in the walls of blood vessels, where it squeezes the stream of blood flowing through the vessels to help maintain blood pressure
Cardiac Found in the heart The walls of the heart's chambers are composed almost entirely of muscle fibers. Its rhythmic, powerful contractions force blood out of the heart as it beats.
How does movement occur? The motor cortex sends an electrical signal through the spinal cord and peripheral nerves to the muscles, causing them to contract The motor cortex on the right side of the brain controls the muscles on the left side of the body and vice versa
The cerebellum coordinates the muscle movements ordered by the motor cortex
Movement continued Sensors in the muscles and joints send messages back through peripheral nerves to tell the cerebellum and other parts of the brain where and how the arm or leg is moving and what position it's in Muscles move body parts by contracting and then relaxing. Your muscles can pull bones, but they can't push them back to their original position. They work in pairs of flexors and extensors
What is the longest muscle? Sartorius (Quadricep muscle)
What is the smallest muscle? Stapedius (Inside the ear)
What is the widest muscle? External oblique (Runs around the side of the upper body)
What is the biggest muscle? Gluteus maximus (In your buttock)
Sternocleidomastoid Location: Location: Side of the neck Function: Function: Pulls head back and rotates head