Embryonic development Flashcards
what is embryonic and fetal phase development?
embryo: week 8 post fertilisation
Fetal: week 9 onwards
name 3 embryonic cell mass and tissue types
Ectoderm including Epidermis, and nerve tissue.
Mesoderm: skeletal muscle blood, CT.
Endoferm: GIT and respiratory
Carnegie Stages or Horizon
describes morphological characteristics present at a given point at a time
Embryonic limp development at week 3
carnegie stage 7-9. Minor swelling appears at the site of future limb development
Embryo limb development at week 4?
stage 13. bud appears at the level of lumbar myotomes.
Embryo limp development at week 5?
stage 13-15. 11-13.5mm. Limb and buds extend distally towards sacral myotomes and length increases. Lumbar segment is still rounded and the sacral segment tapers distally
in what plane were all segments of the Embryo located from week 3-5?
Transverse plane
In which week there is a distinction between thigh, leg, and foot and describe what happens?
Week 8. Ossification point of Fibula occurs. all basic organ development is complete.
What week do congenital foot deformities occur?
before the 7th embryonic week. Talipes Equinovarus,
describe week 5-foot embryo foot development
Stages 13-15. foot disc recognizable. but toys and rays are not identifiable . Dorsal and plantar surface faces superiorly and begin inward rotationn until parallel with sagittal plane.
Describe week 6 foot development
inward rotation continues, including leg.
Left counter clock wise-Right clockwise
Digital rays become more distinct.
Toes are spread
Describe week 7 foot development
foot structure is clearly recognisable
Plantar surface faces medial, Dorsal surface faces lateral.
Foot is in equnius. The entire lower limb externally rotated
outline the week range for 1st, second and third trimester?
1st: up to week 12
Second: 13-24
third: 25 till birth
when does foetal period start
week 9 till birth
Describe weeks 9-12 of foetal period.
- Organ continues to grow
- Eyelids close
- Nails and teeth dev
-Genitals appear - Liver is making RBCs
Describe week 13-16 of foetal period
skin is transparent
Leg is externally rotated at hip and kees flexed, foot in equnius
week 17-28
Fetus can hear, and swallow- Bone marrow functions
Describe Week 29-40 of fetal period
The brain grows rapidly, Gains weight
Describe the lower limb and foot position in foetal period?
Lower limb remains folded in fetal position for most of 3rd trimester
feet slightly inverted
leg crossed over the other
what is the difference between ossification, ossified and chondrification?
Ossification: bone begins to solidify. Whilst ossified is when it fuses or stops growing
Chondrification: formation of cartilage
