skeletal anatomy and physiology

Question 1

why do we have a skeleton?

Answer 1

• muscle attraction, locomotion and body shape
• protection
• mineral storage
• adaptive biological system
• dectects and processes multiple inputs to produce an appropriate response

Question 2

long bone anatomy

Answer 2

epiphysis
metaphysis
diaphysis

Question 3

flat bones

Answer 3

skull
- osteoblast
- osteocyte
- condensed mesenchyme

Question 4

bone types

Answer 4

sesamoid
short
irregular

Question 5

type of bone tissue

Answer 5

compact / cortical
main weight bearing structure
trabecular / spongy / cancellous
main site of calcium exchange. optimised to provide the greatest amount of support for minimum mass

Question 6

composition of bone matrix

Answer 6

25% water
25% organic components - type 1 collagen fibres
50% inorganic componets - calcium hydroxyapatite metals

Question 7

bone development

Answer 7

intramembranous formation skull - the bone forms directly from mesenchymal cells
endochondral ossification- long bones - bones forma from a cartilaginous template, morphogenesis and growth plate

Question 8

growth plate organisation

Answer 8

• site of longitudinal growth
• chondrocytes arranged in columns
• distict zones
• proliferation and differentation are tightly regulated

Question 9

bone cells

Answer 9

bone marrow- erythrocytes,lymphomytes and cells of the myeliod lineage
osteoblastic lineage
-osteoblasts responsible for bone formation and mineralization
- bone lining cells
- osteocytes
osteoclats responisble for bone resorption

Question 10

physiological factors that impact bone homeostasis

Answer 10

• fluctuations in serum calcium
• changes in mechanical loading
• repair of microdamage
• hormal status

Question 11

osteoclasts and ca2+ homeostasis

Answer 11

• fall in ca2+ leads to PTH release from parathyriod glands
• this elevates ca2+ through a variety of mechanisms
  1. promotes bone reabsorption
  2. activates vitiman D3 in kidney which increases intestinal uptake of Ca2+
  3. increases renal reabsorbtion of ca2+

Question 12

osteoblastic lineage

Answer 12

• derived from stromal precursors that can form either osteoblasts or adipose cells
• osteoblasts synesise the organic matrix of bone and control its mineralization
• when osteoblasts finish making new bone they can differentiate into
• osteocyes
• bone lining cells

Question 13

osteoclats

Answer 13

• form from pluripotent CD34+ mononuclear phagocyte precursors that can form many myeliod cell types
• precursor differentiation is controlled by the growth factor that it encounters at a specific stage of its develpomnet
• responsible for bone resorption
• can be multicellular