The Skeletal SystemSection 2, Chapter 14

Pages 474-481

Your framework, or skeleton, is made up of all the bones in your body.

Your skeleton has five major functions. IT provides shape and support, enables you to move, protects your organs, produces blood cells, and stores minerals and other minerals until your body needs them.

What the Skeletal System Does

The backbone, or vertebral column, is the center of the skeleton.

26 small bones make up your vertebrae that make up your backbone.

A newborn baby’s skeleton is made of cartilage.

Shape and Support

Your skeleton allows you to move.

The muscles pull on your bones to make the body move.

Bones protect many of the organs in your body.

Movement and Protection

Bones also store minerals such as calcium and phosphorus.

Bones, in the skeletal system, make certain red blood cells.

Production and Storage of Substances

Your body contains many small bones rather than fewer large ones.

A joint is a place in the body where two bones come together.

Joints allow bones to move in different ways.

Two kinds of joints- immovable and movable.

Joints in the Skeleton

Some joints in the body connect bones in a way that allows little or no movement.

These joints are called immovable joints.

The bones of the skull are held together by immovable joints.

Immovable Joints

hinge

Be able to identify the types of joints

Ball-and socket

Pivot joint- would be a neck vertebrae

Be able to identify which joints are movable- knee and shoulder. Immovable- skull

What kind of motion does a knee (hinge) joint allow? Backward and forward

Which joint provides the greatest range of movement (ball and socket)? Shoulder

Be able to identify different types of joints

Movable joints are held together by strong connective tissues called ligaments. Hinge joints allow backward to forward motion.

Most joints have a second type of connective tissue, called cartilage, which is more flexible than bone.

Cartilage covers the ends of the bones and keeps them from rubbing against each other.

The spaces in bones are filled with a soft connective tissue called marrow.

Movable Joints

Bones are complex living structures that undergo growth and development.

The femur if the body’s longest bone- it connects the pelvic bones to the lower leg bones.

A tough membrane covers all of the bone through the membrane.

Bones- Strong and Living

Beneath the bone’s outer membrane is a layer of compact bone, which is hard and dense, but not a solid.

These canals carry blood vessels and nerves from the bone’s surface to the living cells within the bone.

Bone Structure

Just inside the femur’s compact bone is a layer of spongy bone. Like a sponge, spongy bone has many small spaces within it.

Spongy bone is found at the ends of the bone.

It is lightweight, but strong.

Bone structure

The spaces in many bones contain a soft, connective tissue called marrow.

Two types- red and yellow.

Red marrow produces some of the body’s blood cells.

Yellow marrow stores fat that can serve as an energy reserve.

Bone Structure

The structure of bone makes it both strong and lightweight.

They are so strong they can absorb more force without breaking than can concrete or granite rock.

About 20% of an average adult’s body weight is bone. It is very lightweight.

Bone Strength

Bones are alive- they contain cells and tissues, such as blood and nerves.

Your body is continuously making new bone tissue.

Sometimes it forms after an accident.

The replacement of cartilage by bone tissue usually is complete by the time you stop growing.

Bone growth

A combination of a balanced diet and regular exercise are important for a lifetime of healthy bones.

Eat a well balanced diet that includes enough calcium and phosphorus to keep your bones strong.

Your bones grow stronger and denser when you exercise.

Taking Care of Your Bones

To determine if a bone is broken, a doctor is most likely to use x ray images.

The injury that occurs when a bone comes out of joint is called a dislocation.

Accidents

As people become older, their bones begin to lose some of the minerals they contain.

Mineral loss can lead to osteoporosis, a condition in which the body’s bones become weak and break easily.

More common in women than men.

Osteoporosis