Bone Disorders (quiz 4)

Question 1

Is rickets a childhood or adulthood disease?

Answer 1

childhood

Question 2

What is rickets?

Answer 2

-usually genetic childhood disease
-bone matrix calcification is incomplete or absent (uncalcified matrix is called osteoid)
-resulting bone is very weak in compression/stress
-systemic- everything is rounded/abducted
-involves vitamin D3 cholecalciferol deficiency or resistance

Question 3

What is the telltale sign of rickets in a young child?

Answer 3

bowing of femur

Question 4

What are the 2 types of rickets?

Answer 4

vitamin D deficiency rickets
-vitamin D is necessary for calcification
-responds to supplementation

vitamin D resistant rickets
-caused by errors in metabolic pathways of calcification
-does not respond to supplementation

Question 5

What is the adult form of rickets?

Answer 5

osteomalacia (bone softening)

has a similar etiology= osteoid not adequately mineralized, but adults do not have epiphyseal growth plates

new growth in adults affects width only because there is no growth plate anymore- the new osteons form but remain poorly or unmineralized and the newly formed bone is weaker than surrounding bone

Question 6

Is osteomalacia localized or systemic?

Answer 6

localized, usually in weight-bearing long bones

Question 7

What are the causes of osteomalacia?

Answer 7

-usually vitamin D deficiency
-inadequate dietary calcium
-hormonal imbalances
-pregnancy or lactation

Question 8

What is osteoporosis?

Answer 8

-the amount of actual bone matrix per unit volume is reduced (bone becomes more porous, compact bone becomes thinner (cortical involution))
-bones become weaker
-systemic

Question 9

What are the causes of osteoporosis?

Answer 9

-post menopausal (most common, loss of anabolic hormone estrogen)
-senile due to old age
-disuse due to lack of mechanical loads
-idiopathic (can be anyone at any age, osteoblasts and osteoclasts are dysregulated)

Question 10

What is osteopetrosis?

Answer 10

-marble bone disease
-abnormally large amounts of bone matrix and highly mineralized bone matrix
-very thick cortical bone
-dense networks of cancellous bone
-large amounts of calcified cartilage
-bone is very brittle and easily fractures (high bone mineral to collagen fiber ratio)
-systemic

Question 11

What is pagets disease?

Answer 11

-also called osteitis deformans
-disrupts the displacement of old bone with new bone
-usually due to poor nutrition
-thickened cortical bone
-coarse, thickened trabeculae
-similar to osteopetrosis but more localized (may affect single bone or multiple bones (foci))

Question 12

What is osteogenesis imperfecta?

Answer 12

-congenital/genetic (inherited autosomal dominant trait)
-imperfectly formed bone
-collagen of bone matrix is affected
-bone is soft and brittle

Question 13

What is ankylosing spondylosis?

Answer 13

ankylosis= abnormal condition of joints immobilized by bone production uniting the bones solidly to one another

ankylosing spondylosis= specifically the pathological ankylosis of the vertebral column (affects the intervertebral foramen and can cause stenosis of the nerves and spinal cord)

Question 14

What are the causes of ankylosis?

Answer 14

-genetic
-induced by trauma
-disease
-surgery

Question 15

What hormones can affect growth and remodeling disorders?

Answer 15

calcitonin, parathyroid hormone, and human growth hormone

Question 16

Which hormone can cause disorders based on too much or little levels before the growth plate closes?

Answer 16

human growth hormone

Question 17

What happens if someone has too little hGH before the growth plate closes?

Answer 17

dwarfism (genetic)

Question 18

What happens if someone has too much hGH before the growth plate closes?

Answer 18

gigantism (usually the result of pituitary disorders)

Question 19

After the growth plate closes, in abnormal conditions, subperiosteal bone deposition results in what?

Answer 19

acromegaly
-coarsening of facial features
-increased bone diameters

Question 20

Which bone disorder is known as “imperfectly formed bone”?

Answer 20

osteogenesis imperfecta

Question 21

Which bone disorder is the result of inherited autosomal dominant trait?

Answer 21

osteogenesis imperfecta

Question 22

Which bone disorder is known as “marble bone disease” and has abnormally large amounts of bone matrix with highly mineralized bone matrix?

Answer 22

osteopetrosis

Question 23

Which bone disorder has high bone mineral to collagen fiber ratio?

Answer 23

osteopetrosis