Dev of skeltal system COLE Flashcards
where do cervical spinal nerves exit?
all others?
above vertebra of same number
below vertebra
what do sclerotomes form?
neural arches and vertebral body
what are the reasons for scoliosis?
failure of formation
failure of segmentation
mixed
where do ribs arise from?
where do they grow into ribs?
what can cervical ribs cause?
zones of condensed mesenchyme lateral to vertebral body
thoracic region only
thoracic outlet syndrome
what does skeletogenesis form?
manubrium, body, xiphoid process
what is pectus carinatum
overgrowth of cartilage causing the sternum to protrude
what is pectus excavatum
overgrowth of costal cartilage, restricts rib expansion, pushes sternum inward
what is sternal cleft
missing sternum
what controls appendicular skeletogenesis?
Hox genes
when does limb development begin?
HL or FL ahead?
week 4
FL ahead
what initiates hindlimb outgrowth?
forelimb?
secreted by what?
TBX4 & FGF10
TBX5 & FGF10
secreted by somatic lateral plate mesoderm
what is Holt-Oram syndrome?
mutation in Tbx5
variable upper limb abnormalities, mostly malformations of carpal bones
what is all of the limb missing called?
part?
amelia
meromelia
what is feet and hands close to the trunk called?
phocomelia
what is expressed in the dorsal AER?
Radical fringe which induces SER2 at the border bw cells
ventral ectoderm expresses what?
Engrailed-1
what happens in the Progress Zone
mitosis and limb lengthening
located below AER
what does the AER express which maintains the progress zone
FGF4 and FGF8
what is produced in the ZPA?
what does it do?
retionic acid –> expression of Shh
directs organization of limb bud & patterning of digits
deteremins A/P axis
what happens in a misrepresentation of of retinoic acid or Shh
mirror image duplication of limb structures
what is polydactyly
due to what?
extra digits
duplication of AER via missexpression of retinoic acid or Shh
in the foot, where is the extra digit usually located?
laterally
what regulates type and shape of bones?
Hox
what does the AER secrete to influence the PZ?
what happens next?
FGFs
develop into distal structures
cells not in the AER range development into what?
proximal
what did Thalidomide do?
messed up the AER –> PZ signals
-limbs failed to grow
what is syndactyly?
webbed fingers or toes
failure of apoptosis
what is brachydactyly?
short fingers or toes
lobster-claw
absence of 1 or more central digits or between digits 2 & 4 is what?
cleft hand or foot
Schwann cells are made of what?
neural crest cells
what makes the motor/sensory axons?
neural tube
what makes skeleton and vasculature?
lateral plate mesoderm
how does the upper limb rotate?
lower limb?
laterally 90 degrees
medially 90
what is mermaid syndrome?
legs fused, sirenomelia
what is acondroplasia?
effects what?
result from what?
dwarfism, pathological changes in epiphyseal plate
long bones
mutation in FGF-R3
what is osteogenesis imperfecta?
brittle bone disease due to CT deformaties
blue sclera
what is talipes equinovarus?
due to what?
what week?
club foot
bone deformaties
6-7
how many original somites were there
how many cervical now?
8
7
