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.