Dev of skeltal system COLE

Question 1

where do cervical spinal nerves exit?

all others?

Answer 1

above vertebra of same number

below vertebra

Question 2

what do sclerotomes form?

Answer 2

neural arches and vertebral body

Question 3

what are the reasons for scoliosis?

Answer 3

failure of formation

failure of segmentation

mixed

Question 4

where do ribs arise from?

where do they grow into ribs?

what can cervical ribs cause?

Answer 4

zones of condensed mesenchyme lateral to vertebral body

thoracic region only

thoracic outlet syndrome

Question 5

what does skeletogenesis form?

Answer 5

manubrium, body, xiphoid process

Question 6

what is pectus carinatum

Answer 6

overgrowth of cartilage causing the sternum to protrude

Question 7

what is pectus excavatum

Answer 7

overgrowth of costal cartilage, restricts rib expansion, pushes sternum inward

Question 8

what is sternal cleft

Answer 8

missing sternum

Question 9

what controls appendicular skeletogenesis?

Answer 9

Hox genes

Question 10

when does limb development begin?

HL or FL ahead?

Answer 10

week 4

FL ahead

Question 11

what initiates hindlimb outgrowth?

forelimb?

secreted by what?

Answer 11

TBX4 & FGF10

TBX5 & FGF10

secreted by somatic lateral plate mesoderm

Question 12

what is Holt-Oram syndrome?

Answer 12

mutation in Tbx5

variable upper limb abnormalities, mostly malformations of carpal bones

Question 13

what is all of the limb missing called?

part?

Answer 13

amelia

meromelia

Question 14

what is feet and hands close to the trunk called?

Answer 14

phocomelia

Question 15

what is expressed in the dorsal AER?

Answer 15

Radical fringe which induces SER2 at the border bw cells

Question 16

ventral ectoderm expresses what?

Answer 16

Engrailed-1

Question 17

what happens in the Progress Zone

Answer 17

mitosis and limb lengthening

located below AER

Question 18

what does the AER express which maintains the progress zone

Answer 18

FGF4 and FGF8

Question 19

what is produced in the ZPA?

what does it do?

Answer 19

retionic acid –> expression of Shh

directs organization of limb bud & patterning of digits
deteremins A/P axis

Question 20

what happens in a misrepresentation of of retinoic acid or Shh

Answer 20

mirror image duplication of limb structures

Question 21

what is polydactyly

due to what?

Answer 21

extra digits

duplication of AER via missexpression of retinoic acid or Shh

Question 22

in the foot, where is the extra digit usually located?

Answer 22

laterally

Question 23

what regulates type and shape of bones?

Answer 23

Hox

Question 24

what does the AER secrete to influence the PZ?

what happens next?

Answer 24

FGFs

develop into distal structures

Question 25

cells not in the AER range development into what?

Answer 25

proximal

Question 26

what did Thalidomide do?

Answer 26

messed up the AER --> PZ signals -limbs failed to grow

Question 27

what is syndactyly?

Answer 27

webbed fingers or toes | failure of apoptosis

Question 28

what is brachydactyly?

Answer 28

short fingers or toes

Question 29

lobster-claw | absence of 1 or more central digits or between digits 2 & 4 is what?

Answer 29

cleft hand or foot

Question 30

Schwann cells are made of what?

Answer 30

neural crest cells

Question 31

what makes the motor/sensory axons?

Answer 31

neural tube

Question 32

what makes skeleton and vasculature?

Answer 32

lateral plate mesoderm

Question 33

how does the upper limb rotate? lower limb?

Answer 33

laterally 90 degrees medially 90

Question 34

what is mermaid syndrome?

Answer 34

legs fused, sirenomelia

Question 35

what is acondroplasia? effects what? result from what?

Answer 35

dwarfism, pathological changes in epiphyseal plate long bones mutation in FGF-R3

Question 36

what is osteogenesis imperfecta?

Answer 36

brittle bone disease due to CT deformaties blue sclera

Question 37

what is talipes equinovarus? due to what? what week?

Answer 37

club foot bone deformaties 6-7

Question 38

how many original somites were there how many cervical now?

Answer 38

8 7