Intro to Skeletal System Flashcards
Functional Roles of Skeletal System (5)
Support of body. Protection of internal organs. levers for skeletal muscles. production of blood cells. Storage of minerals.
Bone: composition
composite = made of diff things. 70% inorganic calcium phosphate crystals (strong, inflexible, resistant to compressive stress. 30% organic collagen fibers (tough but flexible, resits stretching, bending and twisting stresses.
Bone: remodeling
will remodel under influence of forces, will change its shape depending on activity (Ex throwing arm vs serving arm which is thicker b/c lots of force is applied.
Bone: anisotropic (not isotropic)
(isotropic=constant properties) has different strength and hardness depending on its orientation, like wood - so can resist stress in some directions better than others.
Bone cells (4)
connective tissue: osteocyte, osteoblast, osteoclast, osteoprogenitor cells
Osteocyte
mature bone cells that maintain protein and mineral contents in bony matrix
osteoblast
cuboidal bone cells found on outer and inner surfaces of a bone, secrete bone material called osteoid (immature) - organic material. responsible for osteogenesis
osteoclast
bone cells responsible to remove bony matrix and releasing minerals into body. large, multinucleated. - osteolysis
osteoprogenitor cells
bone cells found in outer and inner layers of a bone, important role in fracture repair, “just in case” cells, can form osteoblasts
Structure of Bone: two types
spongy aka trabecular or cancellous - open network of struts and plates, hoolow space is where marrow lives. compact bone - dense and solid
Medullary Cavity
in middle of bone: yellow marrow (adipocytes = fat) and red marrow (mature and immature red and white blood cells)
periosteum and endosterum
every bone is covered with a fibrous, thin and transparent layer: covered outside and inside
Osteon aka haversian System
basic functional unit of mature compact bone - osteocytes organized in cocentric layers around a central canal containing blood vessels supplying the osteon
3 types of joints
fibrous, cartilaginous, synovial
Hinge vs ball and socket joints
hinge joint: unaxial - permits only flexion and extension, like elbow joint. ball and socket: multiaxial - rounded head into concavity, movement on several axis like hip joint
Fibrous Joints
connected by dense connective tissue like collagen - like cranial sutures and inteosseous membranes (syndesmosis) - unites long bones like between radius and ulna. fixed, immovable
Cartilaginous Joints
connected entirely with cartilage, more movement than fibrous but less than synovial
Primary cartilaginous joints
aka Synchondrosis: temporary cartilaginous union between bones - growth plates between ossification centers in long bones, might ossify with age.
Secondary cartilaginous joints
aka Symphysis: permanent - intervertebral discs, pubic symphysis
Synovial Joints
most common, allow movement: bones are united by capsule containing synovial fluid - less viscous than motor oil
bone aka?
osseous tissue - is a type of supporting connective tissue
balance between osteoblast and osteoclast
osteoclast removes matrix and releases minerals, osteoblasts produce matrix that quickly binds minerals
major difference between compact and spongy bone
spongy bone is arranged into parallel struts/branching plates called trabeculae
spongy vs compact bone functional difference
compact: resists a lot of strength from epiphysis to epiphysis, but impacts can easily cause fractures. spongy bone - not as massive, but resists stress applied from many different directions
