Functions of Bones

Functions of Bones Slide 5.2 Copyright © 2003 Education, Inc. publishing as Benjamin Cummings Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage of minerals and fats Blood cell formation Compact vs. Spongy Compact = dense, solid, looks smooth Spongy = open spaces, needle-like pieces Classification of Bones Long – longer than wide, shaft w/heads at both ends. Short – generally cube-shaped & mostly spongy bone(carpals of wrist/tarsals of ankle) Flat – thin, flat and usually curved (skull, ribs sternum) Irregular – doesn’t fit in other categories. (Vertebrae) #4 Long bone Structure Diaphysis = Shaft, compact bone Epiphysis = head of long bone, spongy bone Epiphyseal Plate = “Growth Plate” of children, site of actively dividing cartilage for bone growth. Epiphyseal Line = In adults, bone/Cartilage no longer growing; plate becomes ossified (bone) and a line is seen as a remnant. Periosteum = outside layer/covering of bone Endosteum = inside lining of bone, lining of medullary cavity (site of yellow marrow) #5 Spongy bone – In epiphysis (heads) of long bones (also, “diploe” of flat bones) Compact bone – Diaphysis (shaft) Articular Cartilage – at joints to decrease friction, Ends of epiphysis of long bones. #6 Yellow Marrow = Fat, stored inside medullary cavity of long bones (adult) Red Marrow = Site of Red blood Cell product. Spongy Epiphysis(head of long bones) in adults In children, entire shaft of long bones #7 diagram #8 Bone markings Condyle = Rounded articular projection Occipital condyle, Medial condyle near knee Sinus = Cavity inside a bone, air/lined w/mucous membrane. Frontal & maxilla of skull. Foramen = hole/opening in a bone Foramen magnum, verterbral foramen Spine = pointed projection of bone Spinous process of vertebrae #9,10 #11, 12 Osteoblast – Build bone Osteoclast – destroy bone Epiphyseal plate = Growth plate of children, Site has actively dividing cartilage only when child. Site ossifies(become bone) as an adult #13 bone growth/remodeling Bones grow due to: Hormones, Stress (mechanical or gravity), Calcium levels in blood… if blood Ca+2 High then Calcium deposited, if blood Ca+2 is low bone degraded #14 Greenstick – Break is incomplete, like a green twig. Compound – bone breaks and exits through skin. #15, 16 Hematoma = Bruise #17,18 Axial skeleton = skull, vertebrae, bony thorax 19, 20, 21 Remember: Eating times; 7am, 12 pm, 5pm Scoliosis – Curvature is Lateral (to the side) Atlas (C1) – articulates with occipital condyles at base of skull…Nod-yes/no Axis (C2) – allows head to “pivot” 24,25,26 Spine is slight “S” shape Tailbone = Coccyx (last part/beneath sacrum) = hole for spinal cord The Bony Thorax = Sternum, Ribs, Thoracic vertebrae Slide 5.31b Copyright © 2003 Education, Inc. publishing as Benjamin Cummings True ribs –Directly connected to sternum by Costal Cartilage False – indirectly connected: Costal cartilage attached to costal cartilage Floating ribs = 2, not attached Figure 5.19a