1. Organization Cell (ex=muscle cell) Tissues (many of the same types of cells ex muscle tissue) Organ (many tissues that work together ex heart) Organ system level (many organs work together ex circulatory system) Organism level (many organ systems work together)

2. Bones and ligaments

3. Bone Structure Compact bone – hard outer surface Spongy bone – Swiss cheese like matrix interior. To cushion impact. Bone marrow – source of red and white blood cells Haversian Canals – blood vessel canals through compact bone

4. osteoporosis Disease of the bone, causes of which are largely unknown. –Mineral deficiencies promote disease, especially Calcium. –Decrease in bone density –Predominantly older women –Prevention – Get plenty of Calcium at a young age, exercise helps build bone strength

5. Joints – 4 types Ball and socket – all directions –Shoulder and hips Pivot joints – twist around –Arm, vertebrae Hinge joints – lever or hinge action –knees, fingers, toes Gliding – slide past one another –Wrist, ankle

6. Ligaments TOUGH connective tissue that links bones to bones

7. Ligaments Connect bone to bone (joints)

8. Tendons Collagen connective tissue that links bone to muscle. When muscle contracts, pulls on tendon, moves bone.

9. Muscles and Muscular Contraction

10. 3 types of muscle cells Smooth muscle – internal organ walls, blood vessels (enables dilation and contraction) –Sheets of cells, all acting in concert –Many work together to squeeze –Involuntary muscle

11. Cardiac Muscle –Only found in heart –Striated –Involuntary –group of cells contract together

12. Skeletal Muscle Voluntary muscle Multinucleated Striated The muscles in your arms, legs, etc.

13. Skeletal cont… Structure: Muscle  Fasicle  Myofiber (cell)  Myofibril (with many sarcomeres)  Myofilaments Many myofibers connected lengthwise through entire fiber Many mitochondria Many nuclei (why? The multiple nuclei arise from the fact that each muscle fiber develops from the fusion of many cells (called myoblasts).

14. Skeletal cont… Sarcomere (small part of myofibril) –Made up of thin (Actin) and thick (Myosin) filaments –Thin slide across thick

15. Contraction – Sliding Filament Theory When muscle contracts its shortens. When muscle relaxes it DOES NOT lengthen beyond relaxed state Actin and Myosin slide across one another (they do not shorten or lengthen) Myosin head binds actin and pulls it, causing sliding. Requires help of Calcium and _______. ATP

16. Actin/Myosin animation