1. Musculoskeletal System - Bones Homeostasis Bone Function Bone Structure Bone Growth

2. Homeostasis “steady state” Need to maintain balance between intracellular and extracellular fluid. 3 points: Each cell metabolizes All cells contribute to the body Combined contributions = stable ECF

3. Homeostasis 3 players Sensory receptor: sense change in environment; ex) neurons Integrator: processes info; ex) brain Effectors: carry out response; ex) muscles and glands 2 types of feedback: Negative and Positive

4. Homeostasis Negative Feedback Reverses the altered condition Ex) maintaining body temperature Positive Feedback Intensify the change from the original condition Ex) oxytocin in giving birth

5. Bone Function 5 major functions Movement Support Protection Mineral Storage Blood cell formation

6. Bone Structure Made of both living and non-living cells Living= osteocytes Non-living = mineralized matrix of collagen, protein, carbs, and lacunae

7. Bone Structure 2 kinds of bone tissue: 1. Compact bone: Outside of bones Dense & solid Made of collagen = tensile strength Made of osteons which surround canals that carry blood vessels and nerves 2. Spongy Bone: Inside Flattened struts Can contain red marrow which makes blood cells Can contain yellow marrow

8. Bone Structure Red bone marrow = makes red blood cells, platelets, and most white blood cells Yellow bone marrow = consists mainly of fat cells. Can be converted back to red marrow.

9. Bone Growth Start with cartilage template Growth continues at epiphyses; triggered by GH Remodeling= the process of growing or breaking down bone tissue Osteoblasts = deposit bone Calcitonin triggers uptake and production Osteoclasts = breakdown PTH triggers enzyme production that breaks down bone

10. Bone Growth The skeletal system helps maintain Calcium level homeostasis. http://bcs.whfree man.com/thelifew ire/content/chp42 /4202003.html http://bcs.whfree man.com/thelifew ire/content/chp42 /4202003.html

11. Skeleton 206 bones Divided into: Axial Skeleton Head to toe vertical axis Appendicular Skeleton Hanging appendages Ligaments Connect bone to bone Tendons Connect muscle to bone

12. Axial Skeleton Down the center of the skeleton: Skull Vertebrae Ribs Sternum

13. Appendicular Skeleton The appendages of the body. Pectoral Girdle: Ex) shoulder blade, arm bones, and fingers Pelvic Girdle Ex) pelvis, leg bones, and toes

14. Joints Areas of contact/near contact between bones. 3 types: Synovial Have a cavity filled with synovial fluid. Most flexible joints Ex) knee Cartilaginous Somewhat flexible Ex) disk b/w vertebrae Fibrous No cavity b/w bones Not flexible Ex) skull bones Fibrous: A & B. Cartilaginous C & D Synovial E - J