Exam 4 - Bone 2 Flashcards
Bones increase in length
- interstitial growth of EPIPHYSEAL PLATE
- EPIPHYSEAL LINE is left behind when cartilage is gone
Bones increase in width
- OSTEOBLASTS lay down matrix in layers on outer surface and OSTEOCLASTS dissolve bone on inner surface
Wolff’s law of bone
(bones remodeled throughout life)
architecture of bone determined by mechanical stresses through action of osteoblasts and osteoclasts
EX) greater density and mass of bone of athletes or manual worker is an adaptation to stress
size and shape of a bone determined…
genetically but can be modified and influenced by nutrition and hormones
Lack of calcium, protein, and other nutrients during growth and development can…
cause bones to be small
Vitamin D
- necessary for absorption of calcium from intestines
- can be eaten or manufactured in the body
Rickets
lack of vitamin D during childhood
Osteomalacia
lack of vitamin D during adulthood leading to softening of bones
Vitamin C
- necessary for COLLAGEN SYNTHESIS by osteoblasts
Scurvy
deficiency of vitamin C
What does lack of vitamin C also cause?
Causes wounds not to heal, teeth to fall out
Growth hormone
- from ANTERIOR PITUITARY
- stimulates interstitial cartilage growth and appositional bone growth
Thyroid hormone
required fro growth of all tissues
sex hormones
EX) estrogen and testosterone
- cause growth at puberty, but also cause closure of epiphyseal plates and cessation of growth
- they have a DUAL purpose: to enhance and inhibit growth
Growth rapid at puberty
- hormones stimulate osteogenic cells, chondrocytes, and matrix deposition in growth plate
- GIRLS GROW FASTER THAN BOYS and reach full height earlier (estrogen has stronger effect), but males growth for a longer period of time and taller
Teenage use of anabolic steroids
results in premature closure of growth plate and short adult stature
Fracture
typically caused by SIGNIFICANT TRAUMA
car accident, fall, athletics, etc.
Pathologic fracture
occurs w/ little if any trauma in bone weakened by disease
bone cancer or osteoporosis
open fracture
break in the skin
Comminuted fracture
multiple pieces
Greenstick fracture
partial fracture (disruption of only one side of bone)
Impacted fracture
one side of fracture driven into the interior of other side
Pott’s fracture
distal FIBULAR fracture
Colles’s fracture
distal RADIAL fracture
Stress fracture
microscopic fissures from repeated strenuous activities
Oblique fracture
similar to transverse fracture but at an angle
Healing of a fracture normally takes…?
8-12 weeks (longer in elderly)
Where does the pain from a fracture come from?
Periosteum
Process of healing a bone (refer to slides for details)
- Hematoma formation
- Soft callus formation
- Hard callus formation
- Bone remodeling
Closed reduction
fragments are aligned w/ manipulation and casted
Open reduction
surgical exposure and repair w/ plates and screws
When is electrical stimulation used for fractures?
used on fractures if 2 months of healing is necessary
Orthopedics
area of medicine specialized in the prevention and correction of injuries and disorders of the bones, joints and muscles
Osteoporosis
bones lose mass and become “brittle” (loss of organic matrix and minerals)
- risk of fracture of hip, wrist, vertebral column increased
- complications (pneumonia and blood clotting)
Who is at a greater risk for osteoporosis
postmenopausal white women at greatest risk
By age 70, what is the average loss of bone mass?
30%
Who rarely suffer symptoms of osteoporosis?
Black women
What maintains density in both sexes by inhibiting bone resorption?
Estrogen
What produce estrogen in men?
Testes and adrenals
Osteoporosis in women (dealing w/ estrogen)
Rapid loss after menopause, if body fat too low or w/ disuse during immobilization
ERT
From of treatment for osteoporosis
- slows bone resorption, but INCREASES RISK OF CANCER, STROKE, AND HEART DISEASE
PTH
Form of treatment for osteoporosis
- slows bone loss if given as daily injection
- FORTEO increases density by 10% in 1 year
- MAY PROMOTE BONE CANCER
Best treatment for osteoporosis
PREVENTION
- exercise
- calcium intake (1,000 mg/day) between ages 25 and 40
