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Ch. 14.3 Notes
The Muscular System
The Muscular System
• There are about 600 muscles in the human body.
• Muscles have many functions such as:– Keep your heart beating– Pull your mouth into a smile– Move the bones of your skeleton– Expand your chest so you can breathe
Types of Muscles
• There are 3 types of muscle tissue:– Skeletal– Smooth– Cardiac
Skeletal Muscle
• Skeletal muscles are attached to the bones of your skeleton and provide the force that moves your bones.
• These are the muscles we normally think about: – Biceps– Abs– Gluteus Maximus
• A tendon is a strong connective tissue that attaches muscle to bone.
• Remember that ligament was a connective tissue from bone to bone.
• Skeletal muscles look like they have stripes so sometimes we call them striated muscles.
• So, Skeletal muscles = Striated muscles
Smooth Muscles
• The inside of many internal organs, such as the stomach and blood vessels, contain smooth muscle.
• Unlike skeletal muscles, smooth muscle cells are not striped (striated). They react much more slowly and do not tire as easily.
Cardiac Muscle
• THIS IS FOUND ONLY IN YOUR HEART!
• Cardiac = Heart
• They are a little like skeletal and smooth muscles.
• They are striated (like skeletal), but they do not get tired (like smooth).
• If your heart got tired – YOU WOULD DIE!
2 Categories of Muscles
• The three types of muscles (skeletal, smooth, and cardiac) can be divided into 2 categories:– Voluntary (You can move it when you want to)– Involuntary (It moves all by itself without
thinking)
Voluntary or Involuntary?
• Heart• Biceps• Abs• Diaphragm (lungs for breathing)• Eye lids• Toes• Stomach• Blood Vessels
Muscles at Work
• Because muscle cells can only CONTRACT (get shorter), not extend, skeletal muscles must work in pairs.
• While one muscle contracts, the other muscle in the pair relaxes to its original length.
Guess the Pair
• Bicep
• Abs
• Triceps
• Gluteus Maximus
• Hamstring
• Calf
Muscular Strength and Flexibility
• Regular exercise is important for maintaining both muscular strength and flexibility.
• Exercise makes individual muscles cells grow in size.
• As a result, the whole muscle becomes thicker.
• Stretching warms up the muscles and keeps them limber to help prevent injuries.
Injured?
• Sometime, even if you are careful, you can get injured.
• A muscle strain, or pulled muscle, can occur when muscles are overworked or overstretched.
• Tendons can also be overstretched or partially torn.
• After a long period of exercise, skeletal muscles can cramp.
• A muscle cramp is when the entire muscle contracts strongly and stays contracted!
• It is important to follow your doctors advise if you have a muscle or connective tissue injury.
• Sometimes they are so bad you have to have surgery.