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Flashcards in bone anatomy and physiology Deck (20):

how many bones in axial skeleton

- vertebral column, ribs, skull
- 80 bones (protection of main organs)


how many bones in appendicular skeleton

- pelvis / shoulder girdles, upper and lower limbs (weight bearers)
- 126 bones


what is the function of bone

- support: structural framework of body
- protection: many major organs (axial)
- assist in movement: contraction of muscles with bones
- mineral homeostasis: store and release minerals (Ca and P)
- hematopoiesis: blood cell production, red bone marrow
- fat storage: triglyceride


what are the classification of bones

- long: axis longer than width, weight bearing, strong (humerus / femur)
- short: wrist and ankle
- flat: provide protection, production of blood cells (sternum)
- irregular: vertebra
- sesamoid: develop in tendon, compression between bone and tendon, stabilise (patella)
- sutural: small flat irregular bones of the skull


describe the sutural bones of the skull

- wormian, small extra bone plates
- within sutures of cranial bones
- coronal, lambdoid, sagital, squamous


identifying markings of bones

- tuberosity: rounded projection
- crest: narrow, prominent ridge
- trochanter: large blunt irregular surface
- epicondyle: raised area above condyle
- process: bony prominence
- tubercle: small rounded projection


summary of depressions and openings of bones

- fissure: narrow opening
- foramen: round / oval opening through bone
- fossa: shallow, basin like depression


what is the general anatomy of bones

- external: compact
- internal: spongey / trabecular and marrow
- marrow: fills spaces between trabeculae, yellow (fat) or red (RBC prod.)
- periosteum: connective tissue covers bones
- endosteum: covers internal surface
- short / irregular / flat: thin layer of spongey, covered by compact, covered by periosteum


what is the anatomy of a long bone (whole bone)

- diaphysis: shaft of bone
- epiphysis: ends of bone (enlarged)
- epiphyseal line: allows growth of diaphysis in length, cartilage (young), bone tissue (older)
- metaphysis: diaphysis joins epiphysis
- articular cartilage: covers epiphysis and reduces shock and friction
- periosteum: tough sheath of connective tissue, surrounds bone, allow growth in diameter, increased nerve fibres and blood vessels
- nutrient foramen: allows artery and veins to enter bone
- medullary cavity: bone marrow


what is the microscopic anatomy of bone cells

- osteogenic: stem cells in periosteum and endosteum, growth of bone
- osteoblast: form bone become osteocytes
- osteocytes: mature, maintain structure of bone
- osteoclasts: break down (resorb) bone matrix / tissue


compact vs spongey bone

- compact: no visible spaces in matrix, thick-celled diaphysis, tough, strength
- spongey: delicate sheets of bone, ends of long bones


microscopic anatomy of compact bone

- haversian system / osteon: structural unit, ring, lamellae (weight bearing), central canal
- perforating / volkmanns canal: connect blood supply of periosteum, central canals and medullary cavity, nourishment, horizontal
- lacunae: small cavities, contain osteocytes
- canaliculi: hair like canals that connect lacunae to each other and central canal


microscopic anatomy of spongey bone

- consists of trabeculae but no osteons
- irregularly arranged lamellae, osteocytes and canaliculi
- red bone marrow often fills spaces between trabeculae


how are bones formed (intra-membranous ossification)

- mesenchyme (embryonic tissue) develops into connective tissue and musculoskeletal systems
- bone forms directly with mesenchyme within fibrous tissues
- flat bones of skull, mandible


growth of bones

- bone collar forms around hyaline cartilage model
- cartilage in centre of diaphysis calcifies and develops cavities
- the periosteal bud invades the internal cavities and spongey bone forms
- diaphysis elongates and medullary cavity forms, ossification continues
- secondary ossification centre appears in epiphysis
- epiphysis ossify, hyaline cartilage remains only in epiphyseal plate and articular cartilage


how is bone growth regulated

- growth hormone: stimulates epiphyseal plate activity
- thyroid hormone / TSH: modulates activity of GH, lack of TSH = short stature
- testosterone / oestrogen: puberty, promote adolescent growth spurts
- frequent exercise: mechanical stimuli promotes bone growth


what is osteoporosis

- loss of bone mass, resorption occurs faster than bone production
- spongey bone of spine and neck of femur (most susceptible to fracture)
- risk factors: lack of oestrogen (menopause), calcium of vitamin D deficiency, petite body, immobility, low TSH, diabetes
- treatment: calcium / vitamin D supplements, increase weight bearing exercise, hormones, replacement therapy slows bone loss, medicines (increase mineral density)


bones involvement in regulation of body calcium levels

- important during osteoporosis
- calcitonin: increases Ca intake by bone, decreases renal Ca reabsorption
- calcitrol: active ingredient in vitamin D, increases plasma Ca by stimulating Ca absorption in digestive tract and releasing Ca from bone
- PTH: stimulates calcium reabsorption in renal tubules, bone resorption and calcitrol activation


two types of bones growth

- interstitial: length of bones, from epiphyseal cartilage
- appositional: increased thickness, remodelling of all bones by osteoblasts / clasts very dynamic


bone repair of fractures

- closed: bones remain inside
- open: breaking of skin, bone outside body, increased infection rate
- hematoma forms, fibrocartilage callus forms, bony callus forms, bone remodelling