Congenital and Acquired Disease of Bone Development Flashcards Preview

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Flashcards in Congenital and Acquired Disease of Bone Development Deck (55)
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1

____ is bone that has not been mineralized

osteoid

2

What are osteoprogenitor cells?

Pluripotential mesenchymal stem cells. Under CBFA-1 stimulation they can become osteoblasts. They can also become macrophages.

3

____ sense mechanical stress and regulate serum calcium and phosphorous

osteocytes

4

_____ mediates osteoclasts and have PTH receptors

osteoblasts

5

Composition of osteoid

type 1 collagen, 90% of organic part

6

Role of osteoblasts

synthesize osteoid, initiate mineralization, become surrounded by matrix and become osteocytes, mediate osteoclast activity, have PTH receptors

7

_____ are incased in bone and communicate through canaliculi

osteocytes

8

Osteoclasts require what cytokines for differentiation?

IL1,3,6,11, GM-CSF, M-CSF

9

Where do osteoclasts reside?

resorption pits, howship lacunae

10

____ are multinucleated cells responsible for resorption and remodeling.

osteoclasts.

11

What pararcine signals allow precursor cells to produce functional osteoclasts?

Osteoblast/ stromal cell membrane-associated RANK ligand (RANKL) binds to its receptor RANK located on the cell surface of osteoclast precursors. This interaction in the background of macrophage colony-stimulating factor (M-CSF) causes the precursor cells to produce functional osteoclasts

12

what does osteoprotegerin do?

Stromal cells also secrete osteoprotegerin (OPG) which acts as a decoy receptor for RANKL, preventing it from binding the RANK receptor on osteoclast precursors. Consequently OPG prevents bone resorption by inhibiting osteoclast differentiation

13

_____ is the cartilage between ossification centers.

growth plate

14

Growth plate is in which part of the bone?

epiphysis

15

Why are children more prone to osteomyelitis?

richer blood supply

16

Describe the blood supply in growing bone vs mature bone

Growing: blood is supplied to growth plate in epiphysis.In mature bone, metaphyseal vessels penetrate the cartilage plate

17

OI is a family of diseases having in common mutations in _____.

type 1 collagen genes

18

What are the classic subtypes of OI

1- too litte pro-a1 made. 2-Pro-a1 is too short (lethal in urtero. 3) triple helix doesnt form well. 4) pro-a2 is too short

19

OI mode of inheritance

most are AD; 2 is either recessive or new AD

20

What are the 4 major clinical criteria of OI?

osteoporosis, blue sclerae, dintinenesis imperfecta, premature otosclerosis

21

Is OI the only thing you see blue sclera with?

No- things like ehlers danlos and rarely anemia, RA, and myasthenia gravis

22

What are the 2 clinical types of OI?

congenital and tarda

23

_____ is the most common cause of inherited dwarfism and is AD.

Achondroplasia

24

What causes achondroplasia?

reduction in chondrocytes at growth plate,

25

What is the specific mutation associated with achondroplasia?

receptor for fibroblast growth factor 3

26

What do limbs look like with achondroplasia?

short extremities with abnormally wide ends. normal trunk, large head with large forehead, deep set nose, prominent supraorbital ridges

27

What is a danger to life with achondroplasia?

deformity at the foramen magnum where minor trauma can cause compression of brain stem.

28

_____ is a known risk factor for new mutations with achondroplasia.

advanced paternal age

29

What do xrays of osteopetrosis show?

long bones without medullary cavities and misshapen, bulbous ends. Diffusely sclerotic.

30

What causes osteopetrosis?

a failure of osteoclasts to resorb bone tissue, resulting in bone marrow
becoming occluded by weak, woven bone. The bone is brittle (breakable) and crowds marrow; patients are typically neutropenic and anemic.