Embryology

Question 1

Nerulation

Answer 1

folding of the ectoderm stimulated by the notochord

• neural groove
• neural crest

Question 2

Neural groove

Answer 2

forms the entire CNS

Question 3

Neural Crest

Answer 3

migrates into mesoderm to form PNS (*DRG), craniofacial structures, and cardiac tissues

Question 4

Ventricular zone

Answer 4

tick pseudostratified epithelia (neuroepithelia–>neurons and glia)

in adults it is a think layer of ependymal cells

Question 5

marginal zone

Answer 5

outer, most dorsal layer that becomes white matter

Question 6

mantle zone

Answer 6

superficial to epithelia

• alar: sensory neuron: dorsal horn
• basal:motor neurons:ventral horns

Question 7

Level of spinal cord during development

Answer 7

3 mo gestation: full length spinal cords
Birth: LV4/LV5
Adult: LV1/LV2

Question 8

Spina Bifida

Answer 8

Family of neural tube defect disorders

occur most in the lumbosacral regions

Question 9

Spina Bifida Occulta

Answer 9

vertebral arches fail to fuse, does not involve meninges, asymptomatic, marked by patch of hair or fat

Question 10

Spina bifida cystics with menigocele

Answer 10

vertebral arches fail to fuse, meninges bulge out

Question 11

Spina bifida cystics with meningomyelocele

Answer 11

vertebral arches fail to fuse and the meninges and spinal cord bulge out

Question 12

Spina bifida with myeloschisis

Answer 12

most sever, neural plate fails to elevate and fold

• spinal cord remains open
• paralysis below this point
• associated with severe neurological defects

Question 13

Resegmentation

Answer 13

week 4
Scleroterme fromthe somites divide into cranial and caudal halves which the fuse to the ones above and below themeselves
–> allows for myotomes to be connected to more than one vertebra which allows for movement `

Question 14

Rib origins

Answer 14

Develop from costal (TPs) processes of the TVs

Question 15

Sternum origins

Answer 15

arises from mesoderm, ossify cranial to caudal

meets up with ribs

Question 16

Pectus excavatum

Answer 16

ribs grow in excess and push in on the sternum

sunken in chest wall

Question 17

Pectus cerinactum

Answer 17

ribs push out on the sternum: pushed out chest wall

Question 18

congential scoliosis

Answer 18

asymmetric fusion of the vertebra

formation of hemivertebrae

Question 19

Klippel feil syndrome

Answer 19

fused CVs as a result of decreased resegmentation during development
results in a short neck, with decreased ROM

Question 20

Poland syndrome

Answer 20

underdeveloped or absent pectoralis muscles
usually unilateral (R)
associated with syndactyly
may be due to lack of blood supply to chest during development

Question 21

Amelia

Answer 21

No limb formation due to lack of AER formation or signaling

Question 22

Meromelia

Answer 22

partial limb formation

Question 23

Phocomelia

Answer 23

flipper-like limb formation (thalidomide)

Question 24

Brachydactyly

Answer 24

shortness of digits

Question 25

syndactylyl

Answer 25

fusion of 2+ digits
most common
lack of apoptosis of mesenchyme b/w/ digits

Question 26

polydactyly

Answer 26

extra fingers or toes due to exs apoptotic zones

Question 27

extrodactyly

Answer 27

absence of digits due to missing apoptotic zones

Question 28

amniotic bands

Answer 28

break of amniotic sac an act as a tourniquet on limb buds or fingers

Question 29

congential hip dislocation

Answer 29

underdeveloped acetabulum and head of femur–>lax joint capsule
dislocates before birth common with breech deliveries
tx: brace that laterally rotates the lower limb or pediatric hip replacement