Chapter 6 - Skeleton System Flashcards
Appositional Growth
Growth in bone width after birth; thickens the bones.
Occurs on cartilage s outside contour (perichondrium). Starts when stem cells at the edge of the perichondrium are converted into chondroblast.
Osteoblast
Create bone matrix
Osteocyte
Mature bone cell that is surrounded by bone matrix.
Maintain the bone matrix and found inside the lacunae
Osteoclast
Remove bone tissue to shape the bone
Osteoprogenitor Cells
Stem/germ cells that give rise to osteoblast
Interstitial Growth
Growth in length at the epiphyseal plate after birth
Process ends between 12 - 25 years
Zones of the Epiphyseal Plate
- Proliferation Zone - cartilage cells undergo mitosis
- Hypertrophic Zone - older cartilage cells enlarge
- Calcification Zone - matrix is calcified
- Ossification Zone - new bone formation
Osteogenesis
Bone growth that start before birth:
- Intramembranous ossification - ends 1-2 years after birth
- Endochondral ossification - ends in early adulthood
Factors Affecting Bone Growth
Nutrition and Hormones
Effects of PTH
Increases Blood Ca+, by:
- Stimulates osteoclast activity
- Increases Ca absorption by intestines by promoting Vitamin D synthesis
- Increase Ca reabsorption from urine
Effects of Calcitonin
Decreases Blood Ca+
Stimulates osteoblast activity
Compound Fracture
Breaks skin of the bone
Simple Fracture
Skin does not break
Incomplete Fracture
Partial break, not all the way
Complete Fracture
Break all the way through the bone
Comminuted Fracture
complete break with more than 2 pieces
Bone Matrix
- Ground Substance (organic - Osteoid)
- Proteoglycans - Protein Fibers (organic - Osteoid)
- Collagen - Calcium Phosphate Crystals (inorganic)
- Must be ingested, deposited to the bone via blood
Intramembranous ossification
Also referred to as dermal ossification. Examples of bones created through this process are flat bones of the skull, mandible (lower jaw), and ribs.
Endochondral ossification
Linear growth of cartilage. Occurs within the cartilage itself. Starts with the division of chondrocytes within the lacuna into two identical cells.
Fossa
Flattened, shallow depression or recess in the bone surface
Canal
Rather large passageway through a bone
Fissure
Elongated, narrow, cleft or slit-like opening through a bone
Foreman
Small, rounded passageway through a bone, through which vessels and nerves pass
Sulcus
Deep narrow groove
Sinus
Hollow space, cavity, or chamber in a bone, normally filled with air
Trochlea
Smooth grooved structure shaped like a pulley
Condyle
Large, smooth rounded prominence
Epicondyle
Adjoining projection to a condyle
Tubercle
Small rounded projection
Trochanter
Large, rough projection
Tuberosity
Large protrusion (located at the proximal and lateral aspect of the shaft of the femur).
