Embryology Flashcards

1
Q

What is a morula and when is it formed?

A

~6 days
16 undifferentiated cells
Undergoes differentiation so inner cells differ from outside

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2
Q

What are the components of a blastocyst?

A
  • Outer layer trophectoderm
  • Inner cell mass
  • Fluid filled cavity
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3
Q

Where does the blastocyst hatch from?

A

Zona Pellucida

day 6

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4
Q

Describe gastrulation.

When does it occur?

A

Convertion of bilayer (of hypoblast and epiblast cells) into a trilaminar embryo, containing 3 layers of Germ cells (Ectoderm, Mesoderm, Endoderm)
14-18 days post-fertilisation

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5
Q

What does the ectoderm give rise to?

A

Skin, CNS

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6
Q

What does the mesoderm give rise to?

A

Muscles, blood, skeleton, heart, kidney

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7
Q

What does the endoderm give rise to?

A

Gut
Lungs
Liver

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8
Q

What happens immediately before gastrulation is complete?

A

Neurulation - differentiation of ectoderm (epiblast) to generate CNS under the control of notocord in the mesoderm of the developing embryo

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9
Q

Where is the notocord located during neurulation?

A

Deep to neural groove

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10
Q

When are the precursors of all internal tissues laid down by?

A

End of week 4
Closure of neural tube
Heart, Face and arms initiated

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11
Q

When does the formation of the upper limb bud start?

A

week 5, 32 days

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12
Q

When do the lungs, liver and kidneys start development?

A

week 8

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13
Q

Where & when does heart tube formation begin?

A

Week 3
Cardiogenic area inferior to notocord
Horseshoe shaped primary heart field forms from day 16-18 from progenitor heart cells

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14
Q

Outline the stages of formation of heart.

A

i. Heart tube formation and fusion (week 3)
ii. Cardiac loop formation (week 4)
iii. Septum formation (week 4-5)
Between LA and RA first
iv. Outflow tract formation

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15
Q

When does the heart tube start to pulsate?

A

Day 32

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16
Q

What are 3 possible congenital heart defects?

A

Septal defects
Great vessel defects
Tetralogy of Fallot

17
Q

What is the Tetralogy of Fallot?

A

RV hypertrophy
Overriding aorta
VSD
Pulmonary stenosis

18
Q

State the stages of human lung development.

A
Embryonic
Pseudoglandular
Canalicular
Saccular
Alveolar
19
Q

In which development stage is surfactant produced?

A

Saccular

20
Q

What is a possible lung defect?

A

Respiratory distress syndrome

due to surfactant deficiency

21
Q

How do you avoid RDS?

A

Glucocorticoid injection to mother 2-3 days prior to delivery to increase in utero production