Skeletal System

1. Skeletal System Chapter 5

2. Components of the Skeletal System • Skeleton subdivided • Axial Skeleton-longitudinal axis of body • Appendicular Skeleton-limbs and girdles • Skeletal System includes • Joints – 3 types • Cartilages – 3 types • Hyaline, Fibrocartilage, Elastic • Ligaments – bone to bone http://www.daviddarling.info/encyclopedia/S/skeleton.html

3. Functions of Bones • Support: framework • Protection: protect soft body organs examples? • Movement: skeletal muscles attached to bones via tendons • Storage: fats in the internal cavities of bones and minerals such as Ca++ and Phosphorus. • Blood cell formation: hematopoiesis (blood cell formation) – marrow cavities of some bones.

4. Classification of Bones • Two types of osseous tissue • Compact bone-dense, smooth, homogeneous • Spongy bone-needlelike pieces of bone and lots of open space. http://www.britannica.com/EBchecked/topic-art/276196/101316/Longitudinal-section-of-the-humerus-showing-outer-compact-bone-and

5. Classification based on Shape • Four groups 1) Long bones – longer than wide, shaft with heads at both ends, mostly compact bone, all bones of limbs except patella, wrist, ankle 2) Short bones – cube shaped, mostly spongy, wrist, ankle, sesamoid bones 3) Flat bones – thin, flattened, usually curved, outer layers of compact bone sandwich spongy, skull, ribs, sternum 4) Irregular bones – don’t fit previous categories, hip bones, vertebrae http://www.aclasta.co.nz/osteoporosis/index.htm

6. Structure of a Long Bone • Diaphysis - shaft • Periosteum - fibrous connective tissue membrane • Endosteum • Sharpey’s fibers - perforating fibers connect periosteum to bone • Epiphyses - ends, compact bone enclosing spongy • Articular cartilage - covers epiphyses, glassy hyaline cartilage-decreases friction • Epiphyseal line - adult bones, epiphyseal plate in growing bones, hyaline cartilage, growth, replaced by bone in puberty http://www.curehandpain.com/images/bone/long_bone.gif

7. Structure of a Long Bone • Medullary cavity – • 1) adults - yellow marrow 2) infants – red marrow - in adults red marrow confined to spongy bone of flat bones and epiphyses of some long bones • Bone Markings – Table 5.1 projections vs depressions ex. Trochanter, Foramen http://www.curehandpain.com/images/bone/long_bone.gif

8. Microscopic Anatomy of Long Bone • Osteocytes – mature bone cells • Lacunae – cavities where osteocytes found • Lamellae – circles lacunae found • Haversian canals – center of lamellae • Osteon – lamellae + Haversian canal • Canaliculi • Volkmann’s canals http://www.octc.kctcs.edu/GCaplan/anat/images/Image269.gif

9. Microscopic Anatomy of Long Bone • Osteocytes – mature bone cells • Lacunae – cavities where osteocytes found • Lamellae – circles lacunae found • Haversian canals – center of lamellae • Osteon – lamellae + Haversian canal • Canaliculi • Volkmann’s canals http://education.vetmed.vt.edu/curriculum/vm8054/labs/Lab8/IMAGES/OSTEON%20AND%20INTERSTITIAL%20SYSTEM.jpg

10. Bone Formation, Growth, and Remodeling • Skeleton formed from bone and cartilage • Embryos vs young children • Cartilage remains in nose, parts of ribs, joints • Ossification – bone formation http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

11. Ossification • Ossification – 2 phases 1) Hyaline cartilage model covered w/ bone matrix by Osteoblasts 2) Cartilage digested opening Medullary cavity -By birth hyaline cartilage models coverted to bone except articular cartilages and epiphyseal plates http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

12. Bone Growth - Lengthening • New cartilage added 2 places – external articular cartilage and ephiphyseal plate • What do each of these do? • Old cartilage digested replaced by bony matrix http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

13. Bone Growth - Widening • Appositional Growth – diameter increase • Osteoblasts in periosteum add bone tissues to diaphysis • Osteoclasts in endosteum remove bone from inner diaphysis • Occurs at about same rate • Controlled by hormones • Ends in puberty – epiphyseal plates converted to bone http://www.personal.psu.edu/staff/m/b/mbt102/bisci4online/bone/bonedevel.jpg

14. Bone Remodeling • 2 Factors 1) Ca++ in blood – bones as storage a) below homeostatic levels – parathyroid glands release PTH into blood. - PTH activates osteoclasts b) above homeostatic levels - Ca++ deposited as calcium salts

15. Bone Remodeling 2) pull of gravity and muscles on bone • Necessary to retain proportions and strength during growth • Bones become thicker and form projections where bulky muscles attached • No stress – bones weaken and atrophy • Ca++ uptake/release and remodeling work together • PTH determines WHEN bone broken down or deposited based on [Ca++] in blood • Muscle pull and gravity determine WHERE bone broken down or deposited

16. Bone Fractures • Occur less often in youth, requires exceptional trauma – twists or smashes • Two types – simple or compound • Comminuted – many fragments • Compression – crushed • Depressed – broken bone portion pressed inward (skull) • Impacted – broken ends forced into each other • Spiral – ragged break due to twisting • Greenstick – incomplete break http://www.hivandhepatitis.com/2008icr/ddw/docs/060308_b.html http://www.itim.nsw.gov.au/index.cfm?objectid=2A54AE6D-1321-1C29-707811D2028CC580

17. Bone Repair • Reduction – closed or open, immobilization to all healing • Hematoma forms – blood vessels broken, blood filled swelling • Fibrocartilage callus formation – mass of repair tissue – cartilage matrix, bony matrix, and collagen fibers, act as splint • Bony Callus forms – osteoblasts and osteoclasts migrate to break, spongy bone callus forms • Bone Remodeling – permanent patch due to stresses http://1.bp.blogspot.com/_57e2KV2nOZs/SAGetjS3TjI/AAAAAAAAAY8/rvhaSyEf-us/s400/bone+repair.jpg

18. Axial SkeletonBones of Skull • Cranium + facial • Cranium – encloses brain tissue • Facial – hold eyes, facial expressions • Joined by sutures – immovable joints • 1 exception – what is it? http://commons.wikimedia.org/wiki/File:Human_skull_side_simplified_(bones).svg

19. Cranium Bones • Frontal – forehead • Parietal – most of cranium, sagittal suture • Temporal – around ear, squamous suture • Occipital – floor and back, lambdoid suture • Sphenoid – butterfly shaped http://commons.wikimedia.org/wiki/File:Human_skull_side_simplified_(bones).svg

20. Facial Bones and Damage http://www.peidental.ca/cleft.html Cleft Palate – incomplete Maxillae formation http://www.physioweb.org/skeletal/skeletal_struct.html http://www.cdc.gov/ncbddd/BD/cleft.htm

21. Infant vs Adult Skull • Infant • Face small to cranium • Cranium ¼ body length • Fibrous regions – fontanels allow compression, brain growth • Adult • Completely ossified • Fused at sutures • 1/8 body length http://www.waukesha.uwc.edu/lib/reserves/pdf/zillgitt/zoo170/diagrams2/diagrams2.html

22. Vertebral Column • Axial Support of body • Skull to pelvis • 26 vertebrae (which type?) connected and reinforced by ligaments • Protects spinal cord • Before birth 33 vertebrae • Separated by fibrocartilage – intervertebral discs http://commons.wikimedia.org/wiki/File:Gray_111_-_Vertebral_column-coloured.png

23. Vertebral Column • Discs and S-shape prevent shock to head and make trunk flexible • Primary curvatures – thoracic and sacral regions • Make C-shape of newborn • Secondary curvatures – cervical and lumbar • Develop after birth • Allow to center weight http://www.sleepywrap.com/index.php?page=stroller-baby-carrier http://commons.wikimedia.org/wiki/File:Gray_111_-_Vertebral_column-coloured.png

24. Herniated Discs http://www.cedars-sinai.edu/5274.html • Drying of discs, weakening of ligaments predisposes older to problem • Also caused due to exceptional twisting • Pressure from disc on spinal cord or nerves – numbness and/or pain http://myhealth.ucsd.edu/library/healthguide/en-us/support/topic.asp?hwid=zm5009

25. Abnormal Spine Curvatures Scoliosis, Kyphosis, Lordosis – All are either congenital, result of disease, due to poor posture, or unequal pull of muscles on spine http://www.merinews.com/catFull.jsp?articleID=147926 http://www.spineuniverse.com/displayarticle.php/article3094.html http://www.nytimes.com/imagepages/2007/08/01/health/adam/9583Lordosis.html

26. Thoracic Cage • Also known as bony thorax • Protects organs in thoracic cavity • Made up of sternum, ribs, and thoracic vertebrae • What kind of bones are these? http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/skeletal.htm

27. Ribs • 12 pair • True Ribs – 1st 7 pair • Attach to sternum via costal cartilages • False Ribs – last 5 pair • Indirectly or not attached to sternum • Floating Ribs – last 2 pair • Lack sternal attachment Intercostal space – filled with intercostal muscle

28. Appendicular SkeletonShoulder Girdle • Consist of 2 bones • Clavicle – collar bone • Scapula – shoulder blades http://www.digitalartform.com/archives/2004/11/anatomy_practic_6.html

29. Upper Limbs • 30 bones • Arm • Humerus • Which type of bone? • Forearm • Radius, Ulna • Hand • Carpal (8) wrist • Metacarpals (1->5) • Phalanges (14) http://commons.wikimedia.org/wiki/File:Human_arm_bones_diagram.svg

30. Pelvic Girdle • Large and heavy bones • Attached to axial skeleton • Bearing weight most important function • Houses reproductive organs, urinary bladder, part of large intestines http://classes.midlandstech.com/bio112/figure7.23pelvic%20girdle%20and%20hip%20bone.htm

31. Lower Limbs • Thigh • Femur – heaviest, strongest bone in body • Leg • Tibia, Fibula • Foot • Tarsals (7) • Metatarsals (5) • Phalanges (14) • Supports weight, level to propel bodies http://www.nlm.nih.gov/medlineplus/ency/imagepages/8844.htm

32. Joints • All bones form joint except 1 • 2 functions – hold bone together, mobility • Classified 2 ways • Functionally – amount of movement • Synarthroses - immovable • Amphiarthroses - slightly • Diarthroses – freely • Where would you find each? • Structurally – separation of body regions at joint • Fibrous - immovable • Cartilaginous - both • Synovial - freely http://apps.uwhealth.org/health/adam/sp/13/100006.htm

33. Joints • Cartilaginous – bone ends connected by cartilage • Intervertebral joints of spine (amphiarthrotic) • Epiphyseal plate of growing long bone (synarthrotic) • Fibrous – boned united by fibrous tissue • Sutures of cranium, connective tissue

34. Joints • Types of Synovial Joints based on shape • Shape determines movement • Plane, hinge, pivot, condyloid, saddle, ball-and-socket • Synovial – bones joined by cavity filled with synovial fluid • All joints of limbs http://www.octc.kctcs.edu/gcaplan/anat/Notes/API%20Notes%20I%20Types%20of%20Joints.htm

35. Diseases of the Joints • Sprains – ligaments, tendons damaged, heal slowly and painful due to low blood supply http://www.epodiatry.com/ankle-sprain.htm • Arthritis – joint inflammation, 100+ diseases, most widespread degenerative disease. • Acute – bacterial infection, Antibiotics • Chronic – Osteoarthritis, Rheumatoid, gouty

36. Osteoarthritis • 85% elderly • “wear and tear” • Articular cartilage • Bone spurs – restricted movement http://www.csmc.edu/5619.html http://www.yorkshirekneeclinic.co.uk/knee-arthritis-treatment.htm

37. Rheumatoid Arthritis (RA) • Chronic inflam. Disease • 3x women • Joints of fingers, wrists, ankles and feet • Symmetrical • Auto-immune • Cartilage destroyed, scar tissue connect bones, ossifies http://www.cedars-sinai.edu/5234.html http://www.bestglucosamine.co.uk/rheumatoid-arthritis.html

38. Gouty Arthritis • Uric acid accumulates in blood, deposits crystals in joints, • Normally affects single joint • Mostly men, rarely before 30 http://gouthomeremedies.info/category/uncategorized http://www.learningradiology.com/notes/bonenotes/goutpage.htm

39. The End