Chapter 7 Skeletal System

Skeleton – 206 bones Framework – bones support the body’s muscles, fat and skin Protection – bones protect vital organs. Levers - muscles attach to bones to help provide movement Production of blood cells- help produce red and white blood cells and platelets Storage – bones store calcium, phosphorus and fats

Long Bone Structure diaphysis – long shaft epiphysis – ends of bone medullary canal – cavity in diaphysis endosteum – membrane that lines medullary canal; keeps yellow marrow intact periosteum – covering of the outside of the bone; contains blood vessels, lymph vessels osteoblasts(cells that form new bone tissue)

Bone Structure Yellow marrow – storage area for fat cells; contains cells that form leukocytes (white blood cells) Red marrow – found some bones such as vertebrae, ribs, sternum and cranium; produces RBC, platelets, and WBC used to diagnose blood diseases used in transplants

Skeletal System Sections Axial Skeleton – forms main trunk of body skull, spinal column, ribs, breastbone Appendicular Skeleton – forms extremities shoulder girdle, arm bones, pelvic girdle, and leg bones

Cranium – protects the brain fontanels – “soft spots”, allow for enlargement of skull as brain grows sutures – where cranial bones join together foramina – openings in bones that allow nerves and blood vessels to enter or leave bone

Spinal Column 26 Bones Purpose is to protect the spinal cord and provide support for the head and trunk

Ribs 12 pairs True Ribs – 7 pairs; attach directly to sternum (breastbone) False Ribs – 3 pairs; attach to cartilage of the rib above Floating Ribs – 2 pairs; floating, no attachment to front of body

Upper Body sternum – breastbone clavicles – collarbones scapulas – shoulder blades; provide attachment of upper arm bones

Arm and Hand humerus – upper arm radius – lower arm on thumb side ulna – larger bone of lower arm with projection called olecranon process carpals – 8; wrist bones metacarpals – 5; palm of the hand phalanges – 14; fingers phalanges

Legs Femur – large bone in thigh Patella – knee cap Tibia – (shin bone) larger weight bearing bone of lower leg Fibula – slender smaller bone of lower leg

Feet tarsals – 7; ankle bones calcaneus – heel bone (largest tarsal bone) metatarsals – 5; instep of foot phalanges – 14; toes phalanges metatarsals

Joints – points where bones connect Bones cannot bend so when 2 bones come together and need to move, they form a joint.

Diseases & Abnormal Conditions Arthritis – inflammation of the joint Fractures – crack or break in bone Simple – complete break of bone with no damage to skin Compound – complete break of bone that ruptures the skin

Diseases & Abnormal Conditions Dislocation – bone forcible displaced from a joint Sprain – twisting action tears ligaments at a joint

Diseases & Abnormal Conditions Osteomyelitis – bone inflammation; infectious organisms cause the formation of an abscess within the bone and an accumulation of pus in the medullary canal Osteoporosis – porosity or softening of the bones

Diseases & Abnormal Conditions Ruptured Disk – herniated or slipped disk, intervertebral disk ruptures or protrudes out of place causing pressure on spinal nerve

Diseases & Abnormal Conditions Spinal Curvatures scoliosis – side to side, curvature of spine kyphosis – hunchback, rounding bowing in thoracic area lordosis – swayback, inward curvature of lumbar region