Skeletal System Skeletal System– Framework of bones and tissues that connect to those bones

Functions of the Skeletal System Support. Bones work like beams that support a building. Protection. Bones protect the internal organs of your body from injury. Movement. Muscles and bones work together to move all the body ’ s parts. Produces materials the body needs Stores materials the body needs

Development of Bones Cartilage– tough, supportive tissue; softer, more flexible than bone (newborn’s skeleton is made mostly of this, most is replaced by bone) Ossification– cartilage hardening to bone-minerals are deposited Periosteum– tough membrane that covers bones; contains cells that form during bone growth and repair

Development of Bones Compact Bone– makes up the outer layer of bones, hard and dense Spongy Bone– lighter in weight, filled with spaces (absorbs shock) Marrow– type of tissue that fills space in spongy bone 2 types: 1. Red marrow- where most blood cells are made 2. Yellow marrow- stores fat

Joints– where two or more bones meet; allow for movement and protect bones from friction and force Ball and Socket Joint– the spherical head of one bone moves inside the cup-shaped socket of another; the joint can move in all directions; Ex: Shoulder and Hip Hinge Joint– joint moves in only one direction like a door hinge; Ex: Knees, Elbows, Fingers, Toes

Joints – Continued Gliding Joint– one part of a bone glides over another bone allowing limited sideways movement; Ex: vertebrae, hand Pivot Joint– end of one bone rotates inside a ring formed by another; joint can move up and down and side to side; Ex: cervical vertebrae (neck)

Joint Connectors Cartilage– connecting tissue that covers the ends of bones and supports certain structures. Ligaments– connecting tissues that hold bones in place at the joints

NAME THE PARTS OF THE BONE

Keeping the Skeletal System Healthy Osteoporosis– condition where bones become brittle and break easily due to significant mineral loss (including calcium, phosphorous, potassium and magnesium) Scoliosis– abnormal curvature of the spine Dislocation– the ends of the bones in a joint are forced out of their normal positions

Mandible(jawbone)

Keeping the Skeletal System Healthy Fracture– break in a bone Simple (closed)– bone is cracked or completely broken in two or more pieces Compound (open) – broken ends of the bone pierce the skin Which is more dangerous and why? Compound because infection can occur more easily

Types of Muscles Voluntary– Muscles that move under conscious will; Example: Skeletal muscle Involuntary– Muscles that move under the direction of the nervous system and various chemicals in the body; Contract and relax rhythmically without the conscious control of the brain; Examples: smooth muscle and cardiac muscle

Skeletal Muscles Muscles that pull on bones to move them. Strong fibers called tendons connect skeletal muscle to bones.

Smooth Muscles Muscles found in various organs, such as the esophagus and stomach

Cardiac Muscles Muscles only found in the heart. They contract and relax about 70 times a minute without ever stopping or getting tired.

Muscle contraction and relaxation (extension)