Skeletal and Muscular System

Skeletal System Body system that consists of bone, cartilage, ligaments, and tendons. Humans have about 206 bones. 4 Functions 1. Stores calcium, phosphorus, and other minerals for use later by the body 2. gives support and structure to the body 3. protects internal organs 4. helps the body to move with the muscles

Structure-parts 1. bone- an organ of the skeletal system a. compact bone- hard outer layer b. spongy bone- soft inner layer 2. cartilage- smooth elastic tissue found mostly at the ends of bones 3. ligament- a connective tissue that connects bone to bone 4. tendon- tissue that connects muscle to bone

Joints joint- a place where two or more bones join A. moveable- bones move 1.ball and socket- shoulder and hip 2.hinge- knee and elbow 3.pivot- neck 4.gliding- wrist B. immoveable- bones don’t move

Muscular System There are over 600 muscles in the human body Function- 1. surround your bones and body organs to protect them 2. give form and support 3.move the body with the skeletal system 4.produce heat

2 Types of Muscles- Structures 1. Flexors- are muscles that bend a joint example- bicep 2. Extensors- are muscles that straighten a joint example- tricep

Muscles work in pairs. When one muscle contracts it pulls on the bone and the other muscle relaxes. Then to move the bone back the muscles do the opposite.

Three Kinds of Muscles 1. Cardiac muscle- a. found only in the heart b. it is striated (striped) c.it is involuntary- you don’t control this muscle

2. Skeletal muscle- a. muscle that is attached to bone b.it is striated (striped) c.it is voluntary- you can control this type of muscle

3. Smooth muscle a. found in the walls of blood vessels, the stomach and other internal organs b.it is not striated (striped) c.it is involuntary- you don’t control these muscles