Skeletal System

The Skeletal System in Action !!

The number of bones Depends on your age Baby has about 275 bones Adult has 206 bones As a baby grows, some of the bones fuse together Ex: Skull

5 Functions of the Skeletal System 1. Movement: Skeletal system provides points of attachment for muscles. Your legs and arms move when the muscles pull on the bones. 2. Support: The backbone is the main support center for the upper body. It holds your head up and protects your spinal cord. Muscle attached to bones!!

5 Functions of the Skeletal System 3. Protection: The bones of your skull protect your brain. Your ribs protect your lungs and heart from injury. 4. Makes Blood: Red and white blood cells are formed by tissue called marrow, which is in the center of the bone.

5 Functions of the Skeletal System 5. Storage: Bones store minerals, such as calcium and phosphorus, for use by the body

Two Major Skeletal System Parts Axial Skeleton: The axial skeleton includes the skull, spine, ribs and sternum. Appendicular Skeleton: The appendicular skeleton includes the appendages of the body, which are the shoulders, arms, hips, and legs.

Skeletal System Bones Four basic bone shapes 1. Long- arms, legs and fingers 2. Short- wrist and ankles 3. Flat- skull and sternum 4. Irregular- spine

Classification of Bones on the Basis of Shape Figure 5.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bone Structure Typical Four Layers: Periosteum: Covers Bones Compact Bone: Lies beneath the periosteum Spongy Bone: Lies beneath the compact bone Bone Marrow: Fills the gaps between the spongy bone

Periosteum Dense, fibrous membrane covering bone; specialized connective tissue covering all bones of the body Contains blood vessels Essential for bone cell survival and bone formation

Compact Bone Hard, strong layer directly underneath the periosteum Gives bones strength Framework of calcium and phosphate that makes the bone hard Contains blood cells and blood vessels

Spongy Bone Located toward the ends of long bones Has many small, open spaces that make bones lightweight

Bone marrow In the center of long bones Some marrow is yellow and composed of fat cells Red marrow produces red blood cells at a rate of 2-3 million cells per second

Bone Formation and Growth Ossification - Process of converting other tissues to bone Healthy bone tissue is always being formed & reformed Osteoblasts – Bone forming cells that deposit the minerals calcium & phosphorus to make bone tissue hard Osteoclasts – Break down bone tissue to release calcium and phosphorus in your blood to maintain healthy levels

Bone Formation Childhood and adolescence: ossification exceeds bone loss Early adulthood through middle age: ossification equals bone loss After age 35: bone loss exceeds ossification

Joints of the Body Ball and Socket Joint: Round end of bone fitting snuggly within another bone. Ex. Shoulder and Hip

Joints of the Body Hinge Joint: Movement at joint in one direction like a door. Ex. Knee and Elbow

Joints of the Body Pivot Joint: Bone resting atop another bone permitting free movement. Ex. Neck, Wrist and Ankles

Joints of the Body Fixed Immovable: Joint does not move Ex. Skull Gliding Joint: Bones slipping over other bones with a free flowing movement. Ex. Knuckles

The Connectors of the Body Cartilage: It acts as a cushion between bones at a joint and protects the bones.

The Connectors of the Body Ligaments: Connect bone to bone

The Connectors of the Body!! Tendon: Attaches muscles to bones

Problems of Skeletal System 1. Fracture – any type of break in the bone First slide copied from other PPT

1a. Hairline Fracture – parts of the bone do not separate

1b. Transverse Fracture – when the break is completely across the bone

1c. Comminuted Fracture – bone shatters in more than 2 pieces

1d. Compound Fracture – break in bone punctures the skin

Problems of the Skeletal System Fracture: Break Dislocation: Out of joint

Problems of the Skeletal System Sprain: Swelling in the joint Arthritis: Inflamed and stiff joints

Problems of the Skeletal System!! Scoliosis: Curvature of the spine Osteoporosis: Brittle bones

Problems of Skeletal System Osteoporosis – condition in which there is a progressive loss of bone tissue Bones weaken and become brittle Caused by a lack of vitamin D and calcium Milk and other dairy products are excellent sources. Weight training and physical activity help increase bone mass

Problems of Skeletal System Scoliosis Lateral, side to side, curvature of the spine. Depending on how serious, can be treated by light exercise, a special brace, or surgery.

Keeping Skeletal System Healthy Consume Calcium and Vitamin D! Found in dairy products such as milk and yogurt Participate in regular physical activity Light weight lifting can enhance bone mass. Exercise promotes better blood circulation which helps to nourish bones

Keeping Skeletal System Healthy Wear protective gear Helmets, pads with contact sports, etc. Keep teeth clean!! Infections from cavities can potentially spread to jaw bone and other facial bones.