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Muscular System. Introduction. There are more than 640 muscles in your body. Almost half of the body’s weight is muscle. 40 % (can be up to 80!) Responsible for body movement and the production of heat Also helps give shape to your body. Types of Muscle.
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Introduction • There are more than 640 muscles in your body. • Almost half of the body’s weight is muscle. 40 % (can be up to 80!) • Responsible for body movement and the production of heat • Also helps give shape to your body
Types of Muscle • Involuntary muscles are not under your conscious control. • You do not have to think about moving them to make them move; they move on their own. • Responsible for activities such as breathing and digesting food.
Types of Muscle • Muscles that are under your conscious control are voluntary muscles.
Types of Muscle Tissue • Three types of muscle tissue • Skeletal, Smooth, and Cardiac • Some are voluntary and some are involuntary
Skeletal Muscle • These muscles are attached to the skeleton. • Provide the force that moves your bones. • They are responsible for movement. • Skeletal muscles are sometimes called striated muscles because the muscle cells appear banded, or striated. • Skeletal muscles are voluntary muscles. • Can react very quickly • Tire quickly
Tendons • Tendons are strong connective tissues that attach muscles to bones.
Smooth Muscle • Smooth muscles are found inside of many internal organs. • They are involuntary muscles. • They work automatically to control certain movements inside your body, such as those used in digestion. • Smooth muscles cells are not striated. • React slowly • Tire slowly
Cardiac Muscle • Cardiac muscle is found only in the heart. • It is involuntary. • Cardiac muscle cells are striated. • Does not tire • Repeated contractions are called heartbeats.
Muscles at Work • Muscles do their work by contracting, or becoming shorter and thicker. • Muscles contract when they receive messages from the nervous system. • Because they can only contract, not extend, they must work in pairs. • When one muscle contracts, the other muscle of the pair relaxes to its original length.
Muscular Strength and Flexibility • Exercise makes individual muscle cells grow in size. • As the muscle cells get larger, the whole muscle becomes thicker. • The thicker a muscle is, the stronger it is. • Stretching and warming up before exercise makes the muscle more flexible.
Muscle Injuries • A muscle strain, or pulled muscle, can occur when a muscle is overworked or overstretched. • Tendons can also become overworked or overstretched. • Muscle cramps occur when the muscle contracts strongly and stays contracted.
Muscles to Know • Biceps • Triceps
Muscles to Know • Quadriceps
Muscles to Know • Deltoid
Muscles to Know • Pectoralis major
Muscles to Know • Gluteus maximus