1. The skeletal system

2. 1.SUPPORT Attachment for tendon, framework for body 2.PROTECTION Ex: cranial bones protect brain 3.ASSISTANCE IN MOVEMENT Work with muscles 4.MINERAL HOMEOSTASIS calcium 5.BLOOD CELL FORMATION hemopoiesis in red bone marrow of select bones 6.TRIGLYCERIDE STORAGE Potential energy reserve in adipose cells of yellow bone marrow

4. 1. diaphysis: shaft 2. epiphyses: ends 3. metaphysis: between diaphysis and epiphysis. Contains epiphyseal plate (hyaline cartilage) in growing bone. Replaced by bone around 18-21 = epiphyseal line

5. 4. Articular cartilage: covers ends of bone to reduce friction 5. periosteum: surrounds bone everywhere there isn’t articular cartilage; bone growth in thickness, assists in fracture repair, serves as an attachment point for ligaments and tendons

6. 6. Medullary cavity (marrow cavity): inside diaphysis that contains fatty yellow bone marrow 7. endosteum: lines the medullary cavity

8. Compact bone tissue Strong/light Makes up most of diaphysis

9. Parts of compact bone OSTEON: repeating unit of the structures 1.Perforating (Volkmann’s) canals: transverse, for blood vessels and nerves 2. Central (haversian) canals: connect with perforating canals; run longitudinally; for blood vessels and nerves

10. 3. Concentric lamellae: rings around central canals 4. Lacunae: spaces between lamellae 5. Canaliculi: fluid-filled; radiating from lacunae in all directions.

12. Spongy bone tissue Does NOT contain osteons Looks spongy; is not soft Forms most of epiphyses and narrow rim around medullary cavity of diaphyses Makes up most of short, flat, and irregulary shaped bones Sometimes red bone marrow

13. Choices: spongy or compact 1.What type of bone tissue is made up of osteons? 2.What type of bone tissue would the patella be made up of?

14. Calcium in bone

15. Bones, neurons, muscle cells, blood clotting, depend on Ca +2 in blood. Too high – heart stops Too low – osteoporosis, breathing stops

16. Stimulus: low blood calcium levels Receptors: cells of parathyroid gland Control center: nucleus of parathyroid cells (parathryoid hormone – PTH) Effectors: osteoclasts activated – releases calcium from bone A negative feedback system Calcium homeostasis

17. Stimulus: high blood calcium levels Receptors: Cells in thyroid gland Control center: nucleus of thyroid cells (secrete calcitonin). Effectors: osteoclasts inhibited: bone absorbs calcium What type of feedback system?