Skeletal System Chapter 7

Functions 1. Support – strong, rigid nature allows for structural support 2. Protection – Shields organs, ribcage surrounds heart and lungs 3. Aid in Movement – serves as place of attachment for skeletal muscles 4. Blood Cell Formation – hematopoiesis: manufacturing process for blood cells, occurs in red marrow 5. Storage – calcium and phosphate, which are needed for muscle contraction, nerve cell functioning, and movement of materials across cell membranes

Bone Structure

Types of Bones Long bone – Greater in length than in width designed to absorb stress from body weight found in arms, forearms, hands, thighs, legs, and feet

Types of Bones Short Bone – equal in length and width (cube shaped) Found in ankles and wrists

Types of Bones Flat Bone – thin and flat Found in cranium of head, ribs, scapulae, and sternum

Types of Bones Irregular – complex shapes Vertebrae, facial bones

Types of Bones Round (sesamoid) Bones – small, nodular, usually embedded in tendons Kneecap

Parts of a Long Bone Diaphysis – long, central shaft of bone (between ends) Epiphyses – extreme ends of a bone, each end forms a joint (articulation) with another bone Articular Cartilage – thin layer of hyaline cartilage along outer surface of epiphyses near joint

Parts of a Long Bone Periosteum – sheet of dense connective tissue that covers bone (except where there is articular cartilage) attaches to outer surface of bones by protein fibers large supply of blood vessels (bone nourishment) contains bone cell called osteoblast (bone growth and repair)

Parts of a Long Bone Compact bone – dense matrix, forms thick walls in diaphysis, thin layer in epiphyses Spongy bone – spaces filled w/ red marrow, occupies epiphyses

Parts of a Long Bone Medullary cavity – surrounded by sponge bone layer; space w/in shaft of long bones that contains yellow marrow (fat storage) Endosteum – thin membrane that lines the interior surface of the medullary cavity