BELL WORK Write about a time you injured a muscle ?

BODY SYSTEMS MUSCULAR SYSTEM

OBJECTIVES  explain the functions of the muscular system.  identify how muscle types differ.  describe ways to keep your muscular system healthy.

MUSCLE FACTS The human body has over 600 voluntary/skeletal muscles Muscles are made of microscopic filaments which contract and slide over each other causing the the muscles to shorten and therefore contract. There are fast-twitch and slow-twitch muscles. The largest muscle is the Gluteus Maximus, the muscles of the buttocks The strongest muscles are: – The Soleus, part of the calf muscle, below the calf muscles, as it can apply the most force. – The Masseter, also known as the jaw muscles

YOUR MUSCLES Your muscular system contains many muscles that perform different functions

YOUR MUSCLES muscular system The group of structures that give your body parts the power to move

TYPES OF MUSCLES skeletal muscles The muscles attached to bones that enable you to move Skeletal muscles are voluntary.

TYPES OF MUSCLES Skeletal muscles are the largest part of the body’s muscular system.

TYPES OF MUSCLES smooth muscles Muscles found in organs, blood vessels and glands Smooth muscles are involuntary.

TYPES OF MUSCLES The mouth, stomach, and lungs are all composed of smooth muscles.

TYPES OF MUSCLES cardiac muscles Muscles found only in the walls of your heart Cardiac muscles are involuntary.

TYPES OF MUSCLES Cardiac muscles work continuously, even when you sleep.

HOW MUSCLES WORK There are two basic and opposite actions that account for all muscle movement.

CONTRACTION The shortening of muscle fibers.

EXTENSION The lengthening of muscle fibers.

MUSCLE MOVEMENT Muscle movement is triggered by impulses.

HOW MUSCLES WORK When you bend your arm, your biceps contract and pull on a bones of your lower arm. At the same time, the triceps extend. 1 When you straighten your arm, your triceps contract and pull on the other bone in your lower arm. At the same time, the biceps extend. 2

PROBLEMS WITH THE MUSCLULAR SYSTEM Muscle strain is caused by small tears in a muscle or tendon. Strains usually occur in large muscles that have been overworked.

PROBLEMS WITH THE MUSCULAR SYSTEM Muscular dystrophy is an inherited disease, and causes skeletal muscle tissue to gradually waste away.

CARE FOR THE MUSCLAR SYSTEM Regular exercise helps maintain the natural tension in muscle fibers, called muscle tone.

CARE FOR THE MUSCLAR SYSTEM Regular exercise also keeps the cardiac muscles healthy.

CARE FOR THE MUSCLAR SYSTEM Eat well.

CARE FOR THE MUSCLAR SYSTEM Warm up before exercising or playing sports.

CARE FOR THE MUSCLAR SYSTEM Cool down after exercising or playing sports

CARE FOR THE MUSCLAR SYSTEM Use exercise or sports equipment properly.

CARE FOR THE MUSCLAR SYSTEM Lift heavy objects properly.