1. Skeletal System Tissue

2. Functions 1.Support-body’s framework 2.Protection- encloses organ systems 3.Movement-joints of bones act as levers that move as muscles contract. 4.Mineral storage- calcium, phosphorus, etc. 5.Hematopoiesis- blood cell formation

3. Skeletal System Includes two types of connective tissue: –Bone –Cartilage Other tissues also discussed: –Blood –Nervous tissue –Loose fibrous tissue –Adipose –ETC.

4. Bone Tissue Refer back to Connective Tissue Notes: Bone Hard calcified matrix filled with collagen fibers Hard tissue gives it a support and protective function

5. Bone Matrix The intracellular substance of bone is made of two components: –In organic salts –Organic Matrix

6. Inorganic salts Calcified and hard nature of bone results from salt minerals. Calcium & phosphate Osteoporosis is characterized by a loss of these bone minerals

7. Organic Matrix Collagenous fibers Protein & polysaccharides (ground substance) –Provide support & adhesion between cellular & fibrous elements All organic substance give bone a plastic like resilience so that applied stress (with in reason) does not result in frequent crush or fractures.

8. Microscopic structure of bone Refer back to Connective Tissue Notes: Bone Compact bone –Contain cylinder Osteons –Osteons contain: Lamellae, lacunae, canaliculi, Haversian canal. –Haversian canals are connected by transverse Volkmann’s canals. Volkmann’s canals contain nerves & blood vessels that carry blood & lymph to osteons.

11. Microscopic structure of bone Cancellous (spongy) bone –Found sandwiched between compact bone. –No osteons –Contains needle like Trabeculae –Bone cells found in trabeculae –Nutrients and waste passed through canaliculi by diffusion –Bone marrow found within spongy bone

12. Bone Cells Refer back to Connective Tissue Notes: Bone Osteoblasts: bone forming cells Osteocytes: mature osteoblasts trapped within lacunae. Osteoclasts: Bone destroying cells

13. Bone Marrow Soft diffuse connective tissue: myeloid tissue Site of blood cell production Found in cavities of long bones & spongy bone.

14. Marrow types Red marrow –Found in all bones of an infant or child’s body –Produces red blood cells Yellow marrow –Red is replaced by yellow marrow as a person ages –Marrow is saturated with fat and no longer active in blood production In adults, ribs, vertebrae, humerus, pelvis, & femur have red marrow

15. Bone marrow transplant

16. Types of Bone Long bones Short bones Flat Bones Irregular Bones

17. Long Bones Long Shaped ends Femur & Humorous are examples of long bone

18. Long bones

19. Short Bones Cube or box shaped Broad Wrist (carpals) & ankle (tarsals) bones

20. Short bones

21. Flat Bones Broad and thin with a flat & often curved surface. Some skull bones, shoulder blades, pelvis, ribs, and sternum are flat.

23. Irregular Bone Often in clustered groups. Various shapes & sizes Vertebrate, sacrum, facial bones are irregular.

25. Parts of a long bone Diaphysis Epiphyses Articular Cartilage Periosteum Medullary (marrow) cavity Endosteum

26. Diaphysis Main Shaft like portion. Hollow cylinder shape Thick compact bone Provides strong support for weight

27. Epiphyses Ends of bone Bulb shape Space near joint for muscle attachments Spongy (cancellous) bone Red marrow fill spaces in spongy bone

28. Articular Cartilage Thin layer of hyaline cartilage Covers joints of Epiphyses Cushions joints or blows

29. Periosteum Dense white fibrous membrane that covers bone (not joints) Fibers of periosteum penetrate bone, sticking them together. Muscle tendon fibers interlace with periosteum fibers as well. Contains bone forming and destroying cells (Osteoblasts & Osteoclasts)

30. Medullary Cavity Tube like hollow space in the diaphysis Filled with connective tissue rich in fat: yellow marrow

31. Endosteum Thin epithelial membrane that line medullary cavity

32. Bone Model Using materials provided and page 191, create a model of a long bone. Parts –Periosteum  plastic wrap –Spongy bone  sponge –Compact bone (diaphysis)  clay – Yellow marrow  petroleum jelly Label each part

33. Regulation of Blood Calcium Levels Skeletal system-Storehouse of 98% of body’s calcium –Maintains constancy of blood calcium levels Calcium acquired during bone formation/remodeling –Homeostasis of calcium ion concentration essential for: Bone formation, repair Blood clotting Transmission of nerve impulses Maintenance of skeletal & cardiac muscle contractions

34. Mechanisms of Calcium Homeostasis Parathyroid hormone –Regulates calcium –Stimulates osteoclasts to breakdown bone matrix & release calcium in blood –Increases renal absorption of calcium into urine –Stimulates vitamin D synthesis Calcitonin –Stimulates osteoblasts, inhibits osteoclasts. –Reduces levels of circulating calcium, keeping it in the bones.

35. Development of Bone Osteogenesis –development of bone from cartilage. Process can happen in two ways: –Intramembranous Osteogenesis which is the direct laying down of bone without the presence of cartilage. –Endochondral Osteogenesis which involves bone formation from cartilage.

36. Epiphyseal plate Cartilage between diaphysis & epiphysis that functions in bone growth. Absent in adults that have stopped growing. Fractures of epiphyseal plate often found in adolescence.

37. Bone Growth and Resorption Bones grow by the combined action of osteoclasts and osteoblasts Osteoclasts enlarge diameter of medullary cavity Osteoblasts build new bone around outside of bone.

38. Bone repair Fracture-break in the continuity of the bone 1.Vascular damage initiates repair. 2.Fracture hematoma-blood clot that occurs after fracture. 3.Hematoma is resorped and a Callus, specialized repair tissue, binds fracture. 4.Callus is then replaced with normal bone tissue. Hematoma Callus New bone tissue

39. Fracture trends Higher in seniors because bone density decreases. Men have a lower rate of fracture because men generally have denser bones then women. Fractures usually happen in thin, flat bones, and especially at the ends of bones.

40. Cartilage Refer to notes: Connective tissue- Cartilage Types of cartilage: Hyaline, Fibrocartilage, Elastic Growth: –Interstitial Growth: Cartilage cells divide and secrete more matrix Seen in childhood –Appositional Growth: Chondrocytes in perichondrium divide and secret matrix Seen in adulthood

41. Fracture Rates Find out the rate of fractures in each age group. Answer the questions. Then as a group (3- 4), create a large graph showing the trend of fractures in the demographics studied. Use ● for women’s line and Δ for men’s line.