Chapter 7 Skeletal system
Skeletal system is made up of- 206 bones in the adult skeleton Composed of cartilage and bone Includes the joint, cartilage and ligament systems Is the internal frame work of the body that allows for motion and protection Always changing due to stress and blood calcium levels Very active and alive tissue
Bone function: Support Protection Movement Storage-minerals and fat Blood cell formation-within bone marrow
Bone types: compact-dense and smooth Spongy-open and rough with many holes
osteoblasts 1. functions in bone deposition by secreting collagen, 2. cannot undergo mitosis osteocytes 1. mature bone cells derived from osteoblasts; 2. principle bone cell, 3. cannot undergo mitosis, 4. maintain daily cellular activities (i.e. exchange of nutrients & wastes with blood) osteoclasts 1. functions in bone resorption (i.e. destruction of bone matrix), 2. important in development, growth, maintenance & repair of bone
Bone classification: Long bones-long and thin with mostly compact bone-femur Short bones-cube shaped and mostly spongy bone-wrist and ankle Flat bones-thin, flattened and curved-spongy bone sandwiched between two layers of compact bone-skull and ribs Irregular bones-do not fit into any of the above categories-vertibra
Bone markings: The ridges, holes and bumps on the bone-where tendons, muscles and ligaments attach along with where nerves and blood vessels pass through the bone
Two major types of bone markings: Projections or processes-growth is outward-words that start with a “T” Depressions or cavities-grooves or indentations-words with a “F” except for facets
Site of muscle attachment-projections: Tuberosity-large rounded projection Trochanter-very large, blunt irregular shaped projection-found on femur only Tubercle-small rounded projection Epicondyle-raised area above a condyle Crest-ridge of bone, very prominent Line-ridge of bone, less prominent Spine-sharp, slender, pointed projection
Joint projections: Condyle-rounded articular projection Ramus-armlike bar of bone Head-bone expansion with narrow neck Facet-smooth, flat-like surface
Bone depressions: Fissure-narrow, slit-like opening Foramen-round or oval opening in bone Groove-furrow Fossa-shallow, basin like depression-on atricular surface Meatus-canal-like passage Sinus-cavity within a bone, filled with air and lined with mucous membrane