The Skeletal System How the Skeletal System Works

The skeletal system consists of bones and connective tissue. 206 bones Bones of the skeleton range from the tiniest bone of the inner ear (about 0.25 cm long) to the longest bone of your thigh (femur) Connective tissues cushion the bones, attach bone to bone, and attach bone to muscles

Your skeletal system has many functions, including: providing support for the body protecting internal tissues and organs from damage acting as a framework for attached muscles allowing movement of limbs and igits producing new red and white blood cells storing fat and minerals, such as calcium and phosphorus

Bones Living tissues formed into different layers Outer layer is hard, densely packed, compact bone Beneath spongy bone, less dense with a network of cavities filled with red bone marrow, where blood cells are produced Some bones contain yellow bone marrow, type of connective tissue that stores fat

Bone Structure Humerus bone – Long bone

Rib bone – Flat bone Wrist bone – short bone

Connective Tissue Three types of connective tissue: Cartilage – strong, flexible act as a cushion between two bones to reduce friction, also act as a flexible structure for soft parts of the body (tip of the nose or outer ear) All bones begin in the embryo as cartilage, early in development the cartilage hardens Ossification process by which bone is formed, renewed, and repaired Ligament is a band of fibrous, slightly elastic connective tissue that attaches one bone to another, attach to bones to create joints: attaches the two bones of the forearm to each other, forming the pivot joint Tendon is fibrous cord that attaches muscle to the bone, muscles contract to move parts of the body.

Cartilage surrounding the knee ossification

ligament tendons

Joints – points at which bones meet some joints do not move (bones of the skull); flexible joints include ball- and socket, hinge joints, pivot joints, and ellipsoidal joints. Joints – points at which bones meet some joints do not move (bones of the skull); flexible joints include ball- and socket, hinge joints, pivot joints, and ellipsoidal joints. Ball and socket joint Hinge joint Pivot joint

Understanding Skeletal Problems Injuries and disorders harm the skeletal system Poor nutrition, infections, sports injuries, and poor posture, degenerative disorders can also be problems Compound fractures – broken end of the bone breaks through the skin Simple fracture broken bones doen not break through the skin Hairline fracture – parts of the bone do not separate Transverse fractures when the fracture is completely across the bone Comminuted fracture when the bone shatters inot more than two pieces

compound hairline

Transverse fracture Comminuted fracture

Injuries to joints can occur from overuse strain or disease Dislocation – bone slips out of place, tearing the ligaments that attach the bone at the joint (reset joint and immobilize until healed) Torn cartilage – sharp blow to a joint or a severe twisting of a joint, (surgery removes pieces of the damaged cartilage) Bursitis – painful inflammation of bursa (fluid-filled sac) that helps reduce friction in the joints Bunions – painful swellings of the bursae in the first joints of big toes ( wearing ill-fitting shoes make bunions worse, larger ones require surgery) Arthritis - inflammation of a joint, from injury, natural wear and tear or autoimmune disease ( immune system mistakenly attacks itself, targeting the cells, tissue and organs of own body)

Dislocation knee cap Torn cartilage

Bursitis Bunions Arthritis

Repetitive Motion Injury Prolonged, repeated movements (sewing or computer work) Carpal tunnel syndrome – ligaments and tendons in the wrist swell (numbness, a tingling sensation in thumb and forefinger, pain and weakness in hand Osteoporosis – progressive loss of bone tissue