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THIS UPLOADED FILE IS A PRESENTATION OF THE SKELETAL SYSTEM OF HUMANS
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- 1. AGNES ZONDO PROFESSIONAL STUDIES 3A STUDENT NUMBER: 201106453
- 2. SKELETAL SYSTEM OF HUMANS LIFE SCIENCES GRADE 11 BONES
- 3. WHAT IS A BONE? Is a specialized connective tissue and is one of the hardest tissues of the body Second only to cartilage in its ability to withstand stress
- 4. FUNCTIONS OF THE BONE Provides mechanical support Provides levers for the action of muscles/help in locomotion Serves as site for storage of calcium in the body Protects vital organs Encloses the blood forming elements of the bone marrow
- 5. STRUCTURAL ELEMENTS OF THE BONE Bone cells Osteoprogenitor cells – stem cells Osteoblasts – forms bone Osteocytes – maintains bone Osteoclasts – resorbs bone Bone matrix Sharpey’s fibers Blood vessels, nerves, lymph vessels (Haversian canals)
- 6. BONE CELLS
- 7. OSTEOPROGENITOR CELLS Stem cells derived from the mesenchyme Possess mitotic potential and the ability to differentiate into mature bone cells Resemble mesenchymal cells and are spindle-shaped, with pale-staining elongated nuclei and sparse cytoplasm (small amount of rough ER and poorly developed golgi complex) Mostly found in the inner portion of the periosteum, in the endosteum, and within vascular canals of compact bone
- 8. TYPES OF OSTEOPROGRNITOR CELLS Preosteoblasts Possess some endoplasmic reticulum and gives rise to the osteoblasts Preosteoclasts Has more mitochondria and free ribosomes and give rise to the osteoclasts
- 9. OSTEOBLAST Associated with bone formation Found where osseous matrix is being deposited Vary in shape, some being cuboidal and others pyramidal, and are frequently in continuous layer suggestive of an epithelial arrangement
- 10. FUNCTIONS OF OSTEOBLAST Contain ribose nucleoprotein concerned with the synthesis of the organic components of bone matrix, i.e. collagen and glycoproteins Contain the enzyme alkaline phosphatase concerned not only with the elaboration of matrix but also with its calcification
- 11. OSTEOCYTES Principal bone cells Are osteoblasts which have become imprisoned within the bone matrix and are lodged inside cavities called LACUNA Have faintly basophilic cytoplasm which can be shown to contain fat droplets, some glycogen and fine granules similar to those of or are present within osteoblasts
- 12. OSTEOCYTES Has fine cytoplasmic processes which extend for some distance and are called radiating canaliculi. These form an extensive continuous communication system among osteocytes
- 13. TWO TYPES OF BONE: COMPACT AND SPONGY BONE
- 14. COMPACT BONE Compact Bone •Compact bone is arranged in units called osteons or Haversian systems. •Osteons (Haversian canal) contain blood vessels, lymphatic vessels, nerves •Surrounding this canal are concentric rings of osteocytes along with the calcified matrix. •Osteons are aligned in the same direction along lines of stress. These lines can slowly change as the stresses on the bone changes.
- 15. SPONGY BONE Spongy Bone •Spongy(cancellous)bonedoesnotcontainosteons. •Itconsistsoftrabeculaesurroundingmanyredmarrowfilledspaces. •Itformsmostofthestructureofshort,flat,andirregularbones,andtheepiphyse soflongbones. •Spongybonetissueislightandsupportsandprotectstheredbonemarrow. Spongy bone -irregular lattice work of bone called trabecula-spaces filled with red bone marrow-osteocytes trapped within calcium matrix
- 16. Factors that affect bone growth 1.Minerals 2.Vitamins 3.Hormones 4.Exercise
- 17. Factors that affect bone growth: calcium Calcium Makes bone matrix hard Hypocalcemia: low blood calcium levels. Hypercalcemia: high blood calcium levels. PhosphorusMakes bone matrix hard MagnesiumDeficiency inhibits osteoblasts BoronMay inhibit calcium loss, increase levels of estrogens ManganeseInhibits formation of new bone tissue
- 18. Factors that affect bone growth: vitamins Vitamin AControls activity, distribution, and coordination of osteoblasts/osteoclasts Vitamin B12May inhibit osteoblast activity Vitamin CHelps maintain bone matrix, deficiency leads to decreased collagen production which inhibits bone growth and repair (scury) disorder due to a lack of Vitamin C Vitamin D(Calcitriol) Helps build bone byincreasing calcium absorption. Deficiencies result in “Rickets” in children
- 19. Factors that affect bone growth: hormones Hormones Human Growth HormonePromotes general growth of all body tissue and normal growth in children Insulin-like Growth FactorStimulates uptake of amino acids and protein synthesis InsulinPromotes normal bone growth and maturity Thyroid HormonesPromotes normal bone growth and maturity Estrogen andIncreases osteogenesis at puberty Testosteroneand is responsible for gender differences of skeletons
- 20. Bone fracture terms Closed/Open Partial/Complete Displaced/Non-displaced Simple/Compound Other Fractures: Spiral Transverse Longitudinal Pathologic
- 22. Steps in fracture repair 1 . Formation of a fracture hematomaImmediately after the fracture, there is a sharp fracture line with associated soft tissue swelling. At the fracture Site, there is abundant hematoma with beginning fibroblastic penetration.
- 23. Steps in fracture repair 2 Fibrocartilaginous CallusFormation At 2 weeks there is much visible callus. There is also bone resorption and osteoporosis, both difficult to see in this case because of the overlying callus. There has been migration of chondroblasts into the area and cartilage is beginning to cover the ends of the fracture. New osteous tissue is produced enchondrally.
- 25. END OF THE LESSON I HOPE THAT WHAT I HAVE PRESENTED TO YOU IS WORTHY AND WILL PROMOTE AWARENESS IN THE PROTECTION AND KNOWLEDGE OF BONES PLEASE TAKE CARE OF YOUR BONES CALCIUM!!!!!!!!!!!!!
- 26. Internal structure of a compact bone
- 27. REFERENCES Shinson Kelly, applied autonomy and physiology: a case study approach, paradigm publishers, 14 july 2012http://www.slideshare.net/KellySHinson/ap-ch05 Dieter95, skeletal system, adams publishers, 19 june 2012http://www.slideshare.net/dieter95/skeletalsystem13385835?qid=1e510902-4081-4834-8643f49e03e658b2&v=qf1&b=&from_search=1 Dawn Chipchase, anatomy and physiology, 18 September 2001http://www.slideshare.net/dchipchase/lesson-1-skeletal-system Ronaldo Quitco, anatomy and physiology, mc graw-hill companies, 15 December 2008 http://www.slideshare.net/ronaldoquitco/skeletal-system-presentation