Exam 2 Flashcards
(122 cards)
Functions of a skeleton
Support Protection Movement Electrolyte balance Acid-base balance Blood formation
Osseous tissue
Connective tissue
Necrosis
Bone death
Shapes of bone
Long bones
Short bones
Flat bones
Irregular bones
Long bones
Arms and legs
Longer than wide
Produce leverage for movement
Short bone
Bones in ankle
Usually function by supporting and gliding
Flat bones
Cranium and ribs
Protection, attachment site for muscles
Irregular bones
Some skull bones
Don’t fit into another category
Bone features
Epiphysis and diaphysis
Epiphysis and diaphysis
Separate in children (growing bone) by the epiphyseal plate (cartilage)
Anatomy of a flat bone
Usually limited marrow
Larger area of spongy bone
Makes sense with its function
Osteogenic cells
Stem cells, found in the endosteum
Osteoblasts
Bone-forming cells
Synthesize bone matrix
Osteocytes
Trapped former osteoblasts
Reside in lacunae and communicate with other cells via gap junction, resort bone matrix, deposit bone matrix, contribute to calcium-phosphate levels in blood and bone density, strain sensors in bone remodeling
Osteoclasts
Bone-dissolving cells, different origin than other bone cells, fusion of stem cells
The matrix
- 1/3 organic matter- (glyco-) synthesized by osteoblasts; collagen, glycosaminoglycans, proteoglycans, glycoproteins
- 2/3 inorganic matter- mostly hydroxyapatite; calcium carbonate; magnesium, sodium, potassium, fluoride, sulfate, carbonate, hydroxide
- contaminants- many mineral contaminants can concentrate in bone; heavy metals (usually not harmful in the bone because they kill your kidneys first); radioactive metals can cause problems; examples: uranium (found in the drinking water in NE NV), radium
Physical properties of bone matrix
-Is a composite material(like wood, fiberglass sports equipment)
-Strong, but brittle(ceramic component, mineral)
-flexible, but weak (polymer, collagen, protein/fly an component)
Wood has to be flexible lignin and brittle/strong cellulose fibers
Bone development
- Ossification- formation of bone
- Growth (long bone and flat bone)- elongation, widening and thickening
- remodeling- 10% of bone is recycled per year in a process called remodeling
Intramembraneous ossification
Formation of flat bones- within a fibrous sheet
Endochondral ossification (long bone usually)
-development in pre-existing hyaline cartilage
Bone elongation
- child’s hand
- epiphyseal plates- when they disappear, it becomes a line
- disappear when growth stops
Epiphyseal plate
Zones of growth
Bone widening and thickening
- similar to intramembraneous ossification
- osteoblasts deposit matrix on the inner surface of the periosteum
- they then get trapped (osteocytes)
- produces circumferential lamellae
- marrow cavity widens- osteoclasts of the endosteum
- bone grows by creating more bone in the inside
Bone remodeling
- bone continually remodeled
- collaboration of osteoclasts(resorb bone and breaks it down) and osteoblasts(lay down bone matrix)
- bone mass is greater in athletes and manual laborers
- osteoclasts respond to electrical charges that come from strain on hydroxyapatite
- if it is out of balance- several different pathologies such as osteoporosis