Please write in complete sentences!! Do Now – 01/06/17 What is the muscular system? About how many muscles do we have in our bodies? Please write in complete sentences!!

Muscular System Mrs. Hill

The Muscular System A group of tough tissues that make your body parts move

there are over 600 muscles in the body There are over 30 muscles in your face alone The strongest muscle is the Heart

Functions of the Muscular System Your muscles are responsible for moving your bones, pumping blood, digesting food, and breathing

A group of muscle cells form a muscle fiber A group of muscle fibers make a fasciculus ( a strand of muscle) Many fasciculi (plural) make a muscle.

Each fiber of muscle is covered by a slippery membrane, or sheath, that allows it to slide easily

*tendons connect muscle to bone Ligament connects bone to bone

Kinds of Muscle Fibers 1. Voluntary- Skeletal Muscle- The muscles you control. Made up of striated muscle fibers (legs, arms) make up 50% of our body weight.

2. Involuntary- Smooth Muscle- Muscles that work without your direct control. Consists of smooth muscle fibers (stomach and intestines).

3. Cardiac Muscle- The Heart- Works on its own 3. Cardiac Muscle- The Heart- Works on its own. Controlled by the autonomic nervous system.

How Muscles Work Nerves cause muscles to contract Muscles work in pairs. One muscle group contracts or shortens as another extends or lengthens. (biceps and triceps)

Your muscles are responsible for moving your bones, pumping blood, digesting food, and breathing

Muscle tone- is the tension of your muscles at rest Muscle tone- is the tension of your muscles at rest. The better conditioned your muscles, the better tone they have.

*Warm up- before exercising you should warm up the muscles by doing some easy stretching and exercises to get the muscles ready for activity.

Types of Muscle Fibers 1. Slow Twitch Fibers (red fibers)- Can do long periods of work before tiring, like jogging. (aerobic exercise- with oxygen)

2. Fast Twitch Fibers (white fibers)- Can do short periods of strenuous, like sprints or weight lifting. (anaerobic exercise- without oxygen)

Red fibers have more myoglobin that can store oxygen in the muscle so it can work longer without tiring Strength training- trains the muscle to do more work without tiring also increases the size of the fibers, but does not increase the number of fibers

Problems of the Muscular System 1. Muscle Soreness (strain)- caused by lactic acid, which builds up in the muscle when you exercise. Stretching and warming up before and after exercise can help with lactic acid build up. Sprain is when a ligament is stretched or torn.

2. Pulled Muscle- muscle sheath is in spasm 2. Pulled Muscle- muscle sheath is in spasm. Ice, stretching, and light weight training may be prescribed.

3. Torn Muscle- muscle fibers are actually ripped or torn away from the bone, surgery may be necessary.

4. Muscle Cramps- Muscle is unable to relax 4. Muscle Cramps- Muscle is unable to relax. Can be injury or fatigue related. Loss of mineral, potassium and sodium, also a cause.

5. Tendonitis- inflammation of a tendon

Muscular Dystrophy- commonly an inherited disorder where the muscles become weak and atrophy (shrink) until walking and basic movement is not possible. There is no cure, but therapy can keep muscles working longer.