Chapter 5 Flashcards
Five Functions of the bones
Support Protection Movement Storage Blood cell formation
Four Shapes of bone
Short
Long
Flat
Irregular
Two Types of bone
Compact: dense, outer layer of bone, organized osteons
Spongy: the squishy stuff we have inside the compact bone, interconnecting trabeculae
Diaphysis
Shaft of long bone
Periosteum
Fibrous connective tissue membrane, covering the diaphysis.
Perforating (Sharpey’s) fibers
Connective tissue fibers that secure periosteum to underlying bone.
Epiphysis
End of long bone
Articular cartilage
Covers the external surface of the epiphysis.
Epiphyseal line
In adult bone, the thin line spanning the epiphysis that looks a bit different.
Originated from epiphyseal plate.
Red marrow
Formation of red blood cells in diaphysis, in infants
Yellow Marrow/Medullary Cavity
Adipose tissue storage in diaphysis, in adults.
Categories of bone markings
- protections/processes
- depressions/cavities
Osteocytes
Mature bone cells, found in lacunae.
Central/Haversian Canals
Vertical blood-bearing canal in bone, around which lamellae circle.
Osteon
Complex consisting of central canal and matrix rings (lacunae)
Canaliculi
Tiny canals that radiate outward from central canals to all lacunae.
Perforating/Volkmann’s Canal
Canals running into the compact bone at right angles to the shaft.
Ossification (and its two phases)
When bones develop using hyaline cartilage as their “model.”
Two phases: 1) Hyaline model is completely covered with bone matrix by osteoblasts.
2) The enclosed cartilage is digested away, opening up a medullary cavity within new bone.
Osteoblasts
Bone-forming cells
Appositional Growth
Osteoblasts in the periosteum add bone tissue to the external face of the diaphysis as osteoclasts in the endosteum remove bone from the inner face of the diaphysis wall.
When bone increases in diameter.
Growth hormone
Most important to long-bone growth
Sex hormone
Most important to long-bone growth during puberty
Osteoclasts
Giant bone destroying cells in bones
Bones are remodeled continually in response to changes in two factors:
1) calcium levels in the blood
2) the pull of gravity and muscles on the skeleton
Parathyroid Hormone (PTH)
Released by parathyroid gland when blood calcium levels drop below homeostatic levels
PTH releases osteoclasts to break down bone matrix and release calcium ions into the blood.
Rickets
Disease of children in which the bones fail to calcify.
Closed/simple fracture
Bone breaks cleanly but does not penetrate the skin.
Open/compound fracture
When bone ends penetrate the skin.
Closed reduction
Bone ends are coaxed back into their normal position by the physician’s hands.