The Skeletal System Incredible Human Machine – Bare Bones https://www.youtube.com/watch?v=GQedanwEfHY

Your BONES Produce blood Protection Give shape. Help move Provide chemical storage Protection  CLICK Shape  CLICK Movement  CLICK

BONES are classified by shape Look at the bones on your table. Classify them…. Long bones – longer than they are wide, usually they have a shaft with heads at both ends. They are composed of mostly compact bone. All bones of the limbs except the wrists and ankles, and patella are long bones Short bones – generally cube shaped, composed mostly of spongy bone, bones of the wrists and ankles, and Sesamoid bones which form within tendons i.e. patella are short bones. Flat bones – thin, flattened and usually curved, composed of two layers of compact bone with a layer of spongy bone in the middle, most bones of the skull, the ribs, and the sternum are flat bones Irregular bones – if they don’t fit into the other categories then they are irregular bones. Mostly spongey Vertebra and hip bones

Bone Structure Bones are composed of connective tissue, chemicals, and fats Solid outer layer -compact bone Composed of Osteons An inner layer of spongy bone a honeycomb of flat, needle-like projections called trabeculae. Bones are organs. Thus, they’re composed of multiple tissue types. Compact Bone consists of multiple cylindrical structural units known as osteons or haversian systems. Imagine these osteons as weight-bearing pillars that are arranged parallel to one another along the long axis of a compact bone. Spongy Bone is interconnecting rods or plates of bone. Like scaffolding. Spaces filled with marrow. Covered with endosteum. Oriented along stress lines Compare compact and spongy bone as viewed with the light microscope Trabeculae: interconnecting rods or plates of bone. Like scaffolding. www.academic.pgcc.edu/~aimholtz/AandP/LectureNotes/ANP1_Lec/Skeletal/BoneTissue.ppt

Note the gross differences between the spongy bone and the compact bone. How are spongy bone and compact bone different? Descriptive words What do you think is the purpose of compact bone? Found in areas of strength like the shafts of long bones What do you think is the purpose of spongy bone? Found along lines of stress, it can transfer stress without breaking www.academic.pgcc.edu/~aimholtz/AandP/LectureNotes/ANP1_Lec/Skeletal/BoneTissue.ppt

BONES are grouped by location Axial skeleton Appendicular skeleton

Vertebral Column, Rib Cage Axial Skeleton Skull, Vertebral Column, Rib Cage Vertebral column: Regions: cervical, thoracic, lumbar, sacral, coccygeal Intervertebral disks: cushion vertebrae; assist in movement, flexibility Ribs: Twelve pairs Bottom two pair floating Sternum: Breastbone: Three bones fused

Shoulder Girdle, Pelvic Girdle, Appendicular Skeleton Shoulder Girdle, Pelvic Girdle, Arms & Legs Pectoral girdle: shoulder: Clavicle, scapulas Pelvic girdles: hip: Coxal bones, sacrum, pubic symphysis Limbs: Arms: humerus, radius, ulna, wrist and hand bones Legs: femur, tibia, fibula, ankle and foot bones

Interesting facts The longest bone in your body is the bone above your knee, the thighbone. Your funny bone isn’t a bone at all. When you were born, you had more than 300 bones. By the time you stop growing, you’ll have 206. Your bones are living. They grow as you get older.