Skeletal System

The Skeletal System •  The skeletal system is

made up of all the bones in your body.

•  The adult human skeleton has 206 bones.

•  Babies actually have around 300 bones! As we grow, some small bones join together to form larger bones.

What does it do for us? Our skeleton… •  Gives us shape and

support, •  Helps us move, •  Protects our organs, •  Produces blood cells,

and •  Stores stuff (like

calcium and fat) until the body needs it.

How are bones connected? •  Bones are connected by

joints. (LIGAMENTS hold your bones together!)

•  Joints allow bones to move in different ways; for example, your elbow joint and your shoulder joint provide different types of motion

•  Some joints do not allow movement (like in your skull).

TYPES of JOINTS 1) HINGE JOINT allows

back-and-forth movement (like the hinge on a door).

Ø Examples: Knee, Elbow

2) BALL-AND-SOCKET JOINT allows wide-range of motion. One bone with rounded end fits into a “cup-like” shape on another bone.

Examples: Shoulder, Hip

TYPES of JOINTS

3) PIVOT JOINT allows one bone to rotate around another.

Examples: Neck (can turn your head from side-to-side.) Forearm (can twist side-to-side).

TYPES of JOINTS

4) GLIDING JOINT allows one bone to slide over another.

Examples: Wrists and Ankles let you bend and flex.

TYPES of JOINTS

Are bones alive? •  Yes! •  The skeletal system,

like all organ systems, is made of up organs (your bones), which are made up of living cells and tissues.

•  Bones grow and develop, and can heal themselves if you break one!

What is on the inside of a bone?

•  Bones contain four main layers:

1.  Outer Membrane: Thin and tough; blood vessels and nerves enter the bone through the membrane.

2.  Compact bone: Hard, dense layer of bone that has small canals carrying blood vessels and nerves.

Canal

What is on the inside of a bone?

3. Spongy bone: This layer has many air spaces like a sponge to make the bones lightweight.

4. Marrow: Inside most bones; red marrow makes blood cells and yellow marrow stores fat.

Keeping Your Bones Healthy •  Diet and exercise are two

ways to keep your bones healthy

•  Eat foods high in calcium and phosphorus, like dairy products, meats, and leafy green vegetables.

•  Exercise gets your bones used to heavier loads, which makes them stronger.

Keeping Your Bones Healthy •  Osteoporosis is a disease

where bones lose minerals and become weak.

•  Osteoporosis mostly affects the elderly.