Anatomy and Physiology Chapter 5 The Skeletal System

Skeleton Greek for “dried up body” Engineering marvel –Light –Strong –Functional Divided into two sub-divisions –Axial- longitudinal axis –Appendicular - limbs and girdles

Bones Contribute to body shape and form 1.Provide Support (Framework) 2.Protection Skull, ribs, vertebrae 3.Movement Muscle attachment sites create levers 4.Storage of fat, Ca, P, 5.Blood Cell Formation (hematopoiesis) in certain bones

Bone Classification 206 bones Made of two types of tissue 1.Compact –Dense –Homogeneous 2.Spongy –Small bone projections –Lots of open space

Bone Shapes Long Bones –Longer than wide –Proximal and distal heads and a shaft –All bones of the limbs except wrist and ankle

Short Bones Cube shaped Mostly spongy Wrist and ankle Includes sesamiod –patella

Flat Bones Thin and flat Two layers of compact around spongy Skull, ribs and sternum

Irregular Bones Junk Drawer Vertebrae and hips

Long Bone Structure Shaft = Diaphysis –Mostly compact bone –Covered in membrane (peirosteum) Secured by Sharpey’s Fibers that penetrate the bone End = Epiphysis –Thin layer of compact over spongy –Covered in articular cartilage(hyaline) –Marked by epiphyseal plate/line (growth plate)

Long Bones The cavity of the shaft = Medullary cavity –Adults fat –Infants red marrow Not smooth but have bumps, holes, and ridges –Attachment sites –Blood vessels and verves