MSK Quiz 1

Question 1

hypocalcemia

Answer 1

decreased serum Ca+ levels leads to decreased activation E of Na+ channels leading to hyperexcited neurons=tetany

Question 2

hypercalcemia

Answer 2

increased serum calcium nervous system becomes depressed QT interval of heart/ slow reflexes/ lack of appetite and constipation

Question 3

Parathyroid hormoin

Answer 3

PTH receptors reside on osteoblasts and trigger bone resorption through rank l activating osteoclasts increasing serum Ca/ PTH regulates calcium retention and phosphate excretion in the kidney./increase 1,25(OH)2D3 synthesis subsequently leading to an increase in calcium absorption from the GI tract

Question 4

1,25(OH)2D3 calcitriol (1-25 dihydroxy vitamin D)

Answer 4

necessary for absortion of Ca+ in GI tract/ promotes both calcium and phosphorous retention in kidney/ necessary for mineralization of the bone

Question 5

calcitonin

Answer 5

released in response to elevated serum Ca+/tumor marker/treatment for bone disorders that involve excessive bone resorption/ inhibits osteoclasts

Question 6

FGF 23

Answer 6

phosphate regulation at the levels of the kidney/absence of FGF23 results in hyperphosphatemia and hypercalcemia due to increased levels of calcitriol.

Question 7

osteoblasts

Answer 7

bone forming cells lay down collegen and non collagen prior to bone mineralization/

Question 8

markers for bone formation

Answer 8

bone-specific alkaline phosphatase and osteocalcin / Procollagen peptides PINP PICP

Question 9

Osteoclasts

Answer 9

mediate bone resorption through the secretion of proteases and hydrogen ions to lower the pH.

Question 10

4-hydroxyproline

Answer 10

makes up collagen helix in bone

Question 11

marker of collagen formation

Answer 11

non helical portions adn the amino PINP and carboxy PICP terminals

Question 12

what gives collagen its strength

Answer 12

tropocollagen

Question 13

periosteal apposition

Answer 13

bones grow in width

Question 14

PTH mechanism on osteoblasts

Answer 14

binds receptor stimulate M-CSF which stimulates the differentiation of hematopoietic stem cells to osteoclasts/ secretes RANKL which activates osteoclasts (also done by IL6) osteclasts are inhibited by osteoprotegerin (OPG

Question 15

Disease states that result in weakened bone.

Answer 15

Disease states that are related to hyperactive and chaotic bone deposition

Question 16

osteoprotegrin

Answer 16

inhibits osteoclasts and stops bone resorption

Question 17

Glucocorticoids

Answer 17

suppress bone formation/ suppress intestinal calcium absorption and can induce osteoclastogenesis/ deplete osteoblasts through suppression of differentiation factors and induction of apoptosis

Question 18

Gonadal hormones

Answer 18

Estrogens are needed for closure of the epiphyseal plates and a lack of estrogen during development results in increased adult height and decreased bone density./Estrogens have been shown to decrease bone resorption

Question 19

cytokines that increase bone resorption

Answer 19

increased levels of IL-1α, IL-1β, TNF-α, TNF-β, and IL-6 result in increased bone resorption.

Question 20

markers for bone resorption

Answer 20

urinary hydroxyproline/ collagen cross links CTX, NTX

Question 21

pagets disease

Answer 21

1) osteolytic phase characterized by excessive osteoclast activation; 2) mixed phase consisting of both osteoclast and osteoblast activity; and 3) osteosclerotic phase characterized by predominant osteoblastic activity and marked sclerosis. 1. Treatment involves the use of bisphosphonates. very high alkaline phosphytase levels/ wavey osteons jigsaw appearance

Question 22

osteoporosis

Answer 22

characterized by increased bone fragility conferring a risk of fractures

Question 23

rickets (osteomalacia)

Answer 23

characterized by disorders in mineral mineralization of the organic matrix through interrupted supply or transport of minerals in renal, intestinal, or bone cell disorders.

Question 24

Osteogenesis Imperfecta

Answer 24

brittle bone disease, is the weakening of bone due to mutations in collagen leading to bone fractures and deformity.

Question 25

Osteopetrosis

Answer 25

1. Osteopetrosis arises due to genetic mutations and can be characterized by absent osteoclast activity. defective osteoclastic bone resorption and disorganized bone structure.

Question 26

Bisphosphonates

Answer 26

Bisphosphonates are selectively taken up by the bone and inhibit osteoclast activation, thereby inhibiting bone resorption.

Question 27

Prolia:

Answer 27

monoclonal antibody directed against RANKL. By blocking interaction between RANKL and RANK it acts to inhibit bone resorption.

Question 28

Intermitten PTH treatment

Answer 28

low dose activates osteblast

Question 29

Hyaline Cartilage

Answer 29

this cartilage type has a glassy-appearing matrix containing type II collagen fibers, glycosaminoglycans (GAGs), proteoglycans, and multiadhesive glycoproteins.

Question 30

Elastic Cartilage

Answer 30

similar structure to hyaline cartilage (it contains chondrocytes, type II collagen, and a gel-like ground substance elastin in the extracellular matrix, which gives this cartilage resilience and pliability. This cartilage type comprises the external ear, the eustacian tube, and the epiglottis of the larynx.

Question 31

cartilage grows in width through

Answer 31

through appositional (from undifferentiated cells of the perichondrium)

Question 32

cartilage grows in length through

Answer 32

interstitial (from chondrocytes dividing within the extracellular matrix

Question 33

campomylic dyspalsia

Answer 33

mutation in sox 9 causes bowing and angulation of long bones hypoplasia of the scapula

Question 34

primary ossification center

Answer 34

diaphysis

Question 35

secondary ossification center

Answer 35

epiphysis

Question 36

intramembranous occification

Answer 36

messenchmal to osteocyte

Question 37

endochondrial ossifiaction

Answer 37

messenchymal to cartalidge to bone

Question 38

biphopsphates are given for

Answer 38

osteoporosis (inhibit bone resoprtion)

Question 39

four main actions of PTH

Answer 39

- increase Ca resorption in kidney - decrease phosphate resorption in kidney - covert 25 hdroxy vit d to active form - increase bone resorption by activating osteoclasts through osteoblasts

Question 40

which cells are responsible for osteoid secretion and mineralization?

Answer 40

osteoblasts

Question 41

osteoarthritis

Answer 41

decreased proteoglycan and collegen type 2/pro inflammatory cytokines degenerate cartiglidge/ joint trauma

Question 42

appositional growth

Answer 42

source of new chondrocytes: cells along inner layer of perichondrium chondroblasts secrete extracellular matrix adn become trapped turning into chondrocytes

Question 43

interstitial growth

Answer 43

source of new chondrocytes: mature chondrocytes in ecm proliferate form isogenous groups of cells

Question 44

epiphysis

Answer 44

caps of long bones

Question 45

epiphyseal plate

Answer 45

growth plate

Question 46

woven bone

Answer 46

crzy looking laid down fist in both endochondrial and intermembranous bone formation

Question 47

which side has activly dividing cells in endochondrial bone formation

Answer 47

epiphysis side---- get big---- calcify and undergo apoptosis near the metaphysis side--- then osteoblasts lay down bone