MUSCULAR SYSTEM: moves all your moving parts

WHAT DOES THE MUSCULAR SYSTEM DO? THE MUSCULAR SYSTEM ACCOUNTS FOR ALL OF THE WAYS THAT THE PARTS OF THE BODY MOVE. EXAMPLES: RUNNING, EATING, BREATHING, DIGESTING FOOD, PUMPING BLOOD THE MUSCULAR SYSTEM HELPS PROTECT YOUR JOINTS AND HELPS CREATE THE HEAT THAT KEEPS YOUR BODY WARM.

What are muscles made of? Muscle fibers: bundles of special cells that make up the muscles. These muscle fibers are made up of long, paired strands of proteins. They are able to contract because of the way their paired strands of proteins are linked. (Like an extension ladder)

MUSCLE FIBERS

ARE ALL MUSCLES THE SAME? 3 types of muscle tissue: 1.Skeletal: striated (striped); the type you can move voluntarily 2.Smooth: involuntary movements; eyelids, internal organs, blood vessels 3.Cardiac: involuntary and striated muscle found only in the walls of the heart.

SKELETAL MUSCLE TISSUE

SMOOTH MUSCLE TISSUE

CARDIAC MUSCLE TISSUE

MUSCLE TISSUE

HOW DO SKELETAL MUSCLES MOVE THE BODY? Skeletal muscles move the body by pulling on bones that meet at joints. The muscles at a movable joint either pull the joint into a bent position or pull it straight. Muscles usually work in pairs, one on either side of the joint. When one contracts, the other relaxes.

MUSCLE CONTRACTION

WHAT CAUSES MUSCLES TO GET BIGGER WHEN YOU EXERCISE? The muscle fibers in the muscle contract repeatedly causing the muscle fibers and the muscle itself to grow in diameter and strength. Repeated moderate exercise (walking) does not increase a muscles diameter, however, it will greatly increases a muscle’s endurance by enabling it to obtain more oxygen.

WHY DO MUSCLES GET TIRED? Your muscles need oxygen in order to produce the energy needed for contracting. Muscles that are working very hard use up all oxygen at hand so less energy is at hand for contraction. What happens if you have used up all of your oxygen but you need to keep going? For example, running from a boogey man? In order for muscles to keep working without oxygen, a process that makes the chemical lactic acid provides a small amount of energy.

ANAEROBIC VS. AEROBIC Aerobic: exercises that involve an increased heart rate for an extended period of time. After 20 minutes, the body begins to burn fat. Anaerobic: short bursts of exertion followed by periods of rest. Bodies develop stronger muscles as a result of anaerobic exercise.