Quiz 4 Flashcards
(218 cards)
3 types of bone cells:
osteocytes
osteoblasts
osteoclasts
3 general bone functions:
mechanical
biomechanical reserve
metabolic
What are the mechanical functions of bones?
protection
shape
movement
sound transduction (hearing)
What is the biomechanical reserve function of bones?
blood production in the marrow
What are the metabolic functions of bones?
mineral storage growth factor storage fat storage acid-base balance detox (store heavy metals) endocrine function (FGF, osteocalcin)
Genetic bone d/o referred to as brittle bone dz:
osteogenesis imperfecta (OI)
born w/defective CT d/t deficiency of type-I collagen
8 subcategories, most incompatible with life
Idiopathic avascular osteonecrosis of the epiphysis of the femoral head leading to an interruption of the blood supply of the head of the femur close to the hip joint:
Legg-Calvé-Perthes syndrome
aseptic necrosis not d/t trauma or septic dz
Softening of bones in children potentially leading to fractures and deformity, and among the most frequent childhood dz in many developing countries:
rickets
MC cause of rickets:
Vitamin D deficiency
also:
calcium deficiency
mb 2° to severe diarrhea/vomiting
Toddlers who contract rickets get a __________ deformity, vs older children who get ______________.
toddler - genu varum
children - genu valgum OR “windswept” - both same direction
Prominent knobs of bone at the costochondral jts of rickets pts are known as:
rachitic rosary - beading of the ribs
d/t deficiency of calcium -> lack of mineralization -> overgrowth of cartilage
Dz characterized by low bone mass and structural deterioration of bone tissue:
osteoporosis
mb generalized loss or localized (i.e. casted limb)
The inc porous nature of osteoporotic bone leads to fragility and inc susceptibility to fractures, esp of the ____, _____, and _____, although any bone can be affected.
hip, spine, and wrist
affects ~10 million in the US [F:M 4:1]
1° osteoporosis is a term used to describe _________ d/t advanced age or menopause.
osteopenia (bone thinning)
2° osteoporosis implies dec bone mass d/t:
- medications (corticosteroids, anticonvulsants, anticoag, chemo, EtOH)
- malabsorption (malnutrition, low vit C or D)
- immobilization
- medical conditions
- hyperparathyroidism
- hypo/hyperthyroidism
- hypogonadism
- Cushing’s
- Addison’s
- DM
- liver dz
- neoplasm (mult myeloma)
- ectopic hormone prodution (PTHrP, ACTH)
T/F: Osteoporosis cannot be reliably detected by plain x-rays until 15% of bone mass has been lost.
False
actually can’t see reliably until 30-40% loss!
T/F: Serum calcium, phosphorus, or alk phos can be measured to dx osteoporosis.
False - serum levels are buffered by bone catabolism, and are NOT diagnostic
Diagnostic testing for osteoporosis:
DEXA scan (dual-energy x-ray absorptiometry)
T/F: Postmenopausal osteoporosis is characterized by a hormone dependent acceleration of bone loss primarily d/t estrogen deficiency.
true
Diminished estrogen results in secretion of cytokines:
which are in large part responsible for __________ activity.
IL-1, IL-6, TNF-alpha
inc osteoclast activity
Risk factors for osteoporosis:
- female sex
- thin / small frame
- low bone mass
- advanced age
- FHx
- PMHx of fracture after 50 y.o.
- Hx of early fracture in 1st degree relative
- estrogen deficiency d/t menopause (esp early/surgical)
- amenorrhea
- anorexia nervosa
- low testosterone in males
- low lifetime calcium intake
- Vit D deficiency
- sedentary lifestyle
- cigarette smoking / excessive EtOH
- Caucasian / Asian descent
Exaggerated curvature of the thoracic spine that results in a rounded or hunched back:
kyphosis
commonly seen in pts w/osteoporosis d/t compression fractures of vertebrae
Dz characterized by high bone turnover with accelerated osteoclast and osteoblast activity:
Paget’s dz (osteitis deformans)
Inc calcification of bone - predilection for inc bone deposition in skull, pelvis, tibia, femur
Clinical signs of Paget’s dz:
Labs:
- bone pain
- bone deformities
- fractures
- markedly elev alk phos