What are the functions of the skeletal system? 10/7

1. What are the functions of the skeletal system? 10/7 What does bone do in our bodies? What are the classes of bone? Where is blood produced? What structural arrangements occur inside bone? What are the structural arrangements of “flat” bone? What are the structural arrangements of “long” bone? Osteoblast vs. Osteoclast activity: How is this a struggle for strength and density vs light weight and weakness? What are three ways to create bone within a human?

2. Paper Content: • Title (include your name as author) • Introduction (a paragraph or two that discusses what the paper is about ¼ -1/2 pages) • Body of paper (1-1 ½ pages) • Conclusions Section (review major points of paper that is ¼-1/2 pages) • Literature Cited list this will be in addition to the 1 ½ - 2 pages of text Single Spaced. • 12 pitch New times Roma font, single spaced 1 inch margins top/sides. • No wiggling out of this one ok? :o) • See grade sheet for distribution of points.

3. Editing and Writing for the paper • Try to find folks who are “critical” when they read what you write. Pride is a terrible thing if it prevents us from taking advice on improving our writing. • References…how many? If you have one or two per paragraph you will be fine. A couple students said there are “limits” in their English class. This does not apply to science. Often times a paper will have one or two references per sentence, though you need not be so strict here. Consider this sentence, how can we improve it? Original: One reputable researcher from Germany recently observed that “…high dietary sodium intake increases the risk of high blood pressure and heart disease in otherwise healthy humans” (Luft, Ada, Hark and Doe, 2003, pg 1089). Better to tell who the researcher is and put their quote into your own words. Also assume that if the person is being used in your paper they are “reputable”. Paraphrase and change to you your own words and cite source: Improved: When persons consume more sodium, their risk of hypertension and heart disease increase (Luft et al 2003, pg 1089). Personal Communications: These are great and should be cited, but do not count towards the six references. For instance do not cite your Aunt Mary a respected Pediatric Surgeon at Mayo Clinic. Instead cite the manuscript she authored on the topic of osteoporosis.

4. Writing Assignment Grade Sheet #1)______#2)_______#3)_________=9 points (3 X 3 points): Are three fully edited rough drafts included and editorial comments made to your paper to improve quality? (You are welcome to have additional people read/edit the paper, just do not include these with the final draft) • ______1 point: Are the proper section headings (Title, Author, Introduction, Body, Conclusion, Literature Cited) used on your final draft? • ______2 points: Are copies of the first page of at least two papers/online source identified by using PubMed or listed in your Literature Cited section? • ______5 points: Is the paper easy to read? Does it contain grammatical errors? • ______3 points: Are references properly cited inside the paragraphs of the paper and are they listed in alphabetical order (by author last name) in the literature cited section. • ______5 pts for library tutorial attendance-if you cannot attend it is only 5 points lost. • ______Total out of 25 pts

5. Why do we need bones? Bones provide the following: • Support- • Protection- • pH/Electolyte Balance- • Hemopoeisis- • Detoxification- Bones are formed via: • Intramembranous Ossification- • Endochondral Ossification- Bone consist of: -Collagen as a structural frame work Problem: weak bone and osteogenesis imperfecta -Hydroxyapatite: Calcium phosphate + Calcium carbonate Problem: vitamin D deficiency, ricketts and soft bones

6. Bones differ with respect to shape and length!There are four classes based on shape/length:

7. Two Types of Bone and Marrow: Both reduce body weight and muscle work! Flat and “Spongy” Bones: Red Marrow- Blood formation- Trabeculae- Long and “Hollow” Bones: Storage Yellow marrow Gelatinous marrow Trabecular stress angle The locations of hemopoeisis change with age! V.I.P.

8. Compact Bone: Osteon- Lamellae- Lacunae/Osteocyte- Canaliculi- Central Canal- Volkman Canals- Nutrient Foramen- Bone stress stimulates osteoblast activity! Why have a hollow core? How do we make bones very strong yet keep them light enough for us to stay mobile?_______+_____=strength

9. Flat Bone is a laminate of two layers of compact bone (no lamellae rings) with spongy bone (trabeculae) that forms a shock absorber between the two layers (red marrow “reticular CT” is found here too!).

10. Long bone-compact bone has many osteons, a hollow medullary cavity, and trabeculae at the ends. Other features include the diaphysis (shaft), epiphyseal plate, and widened epiphyseal ends for articulation.

11. What are the parts of a long bone called? What do they do? Epiphyseal Plate: (hyalin cartilage?) Growth is initiated here! Spongy bone/Trabeculae: Compact (Cortical) Bone: Epiphysis vs. Diaphysis End/Joint vs. Center/Shaft Medullary Cavity Periosteum vs. Endosteum Nutrient Foramina/Foramen:

12. Bones differ with respect to the organization of their interior.Bones can have many well organized or very few osteons and lamellae.

13. What cells inhabit bone and what do they do? Which cells do we want to manipulate and why? Classic fibroblast/migrating Fibroblast: Osteogenic cells develop from fibroblasts and become osteoblasts and osteoclasts Osteoblast  Mature Osteocyte in lacunae Deposition of bone Lacunae and cannaliculi: Osteoclast  More often on surface of bone Resoprtion of bone Pits called Resorption Bays or “Howships Lacunae” Bone Density (strength) is determined by a balance of the activity of osteoblasts and osteoclasts, which constantly work in opposition to each other.

14. What is the proper chemical content of bone? Bone Matrix = Inorganic Contents + Organic Contents Hydroxyapatite + Calcium Phosphate + Calcium Carbonate + Collagen: Effects of pH on matrix? How emphysema effect bone strength? Fibroblasts and Collagen formation: Why does Osteogenesis Imperfecta cause brittle bones? Why does radiation toxicity occur? Radium and Cadmium are both divalent cations that look like Ca++ Osteoblast activity is stimulated along lines of tension/stress in bone! Why may astronauts break bones when they get back to earth? Why do the bed ridden break bones when they leave the bed?

15. You Looked Like This! This is a twelve week old fetus. Why is it dangerous for the bones to be “too” hard at birth? Note the sharp demarcations at the ends of the femur (epiphyseal plates) Note the spaces between the frontal, parietal and occipital bones (fontanels). How is bone formed in our bodies?

16. Ossification is the formation of bone. There are three methods to get this done. Osteoblasts, fibroblasts and collagen are critical for making bone! • 1) Endochondral Ossification: Hyalin Cartilage- Epiphyseal Plate- Plate Closure- • 2) Intramembranous Ossification: Osteoid tissue- Trabelulae- Compact bone deposition- • 3) Ectopic Ossification (soft tissue calculi): Usually pathological May indicate hormonal imbalance Chronic Infection/irritation Atherosclerosis

17. Epiphysis: end of bone Diaphysis: Shaft of boneMetaphysis: place where epiphysis and diaphysis convergeEpiphyseal Plate: Place where bone elongation occurs, this plate disappears when bone growth (elongation) stops.

18. How are Long Bones formed? Endochondral Ossification!“Bone matrix is deposited into the former hyalin cartilage at the diaphyseal end of the epiphyseal plate (metaphysis). Blood vessels inside medullary cavity provide nutrients to red marrow that becomes yellow marrow with age.

20. Why would a fracture across an epiphyseal plate create problems for bone elongation during growth? Why is this not a problem in adults?

21. Jack is my 9 year old, why was surgery needed? Thanks to a Nerf football! 2 pins corrected this. This fracture was located across the proximal epiphyseal plate of the 5th proximal phalanx, and $6,800 for a $1.99 Nerf football. 