Embryology

Question 1

What’s the difference between agenesis, aplasia, hypoplasia?

Answer 1

Types of errors in morphogenesis
Agenesis :Absent organ due to absent primordial tissue.
Aplasia: Absent organ despite presence of primordial tissue.
Hypoplasia: Incomplete organ development; primordial tissue present.

Question 2

What’s the difference between disruption, deformation, malformation?

Answer 2

Disruption: 2° breakdown of previously normal tissue or structure (eg, amniotic band syndrome).
Deformation: Extrinsic mechanical distortion (eg, congenital torticollis); occurs after embryonic period.
Malformation: Intrinsic developmental defect; occurs during embryonic period (weeks 3–8 of development).

Question 3

What is Potter sequence?

Answer 3

oligohydramnios, leading to pulmonary hypoplasia, limb defect, craniofacial abnormality

Question 4

What is amniotic band syndrome

Answer 4

Amniotic band syndrome: Entrapment of fetal parts in fibrous amniotic bands
Clinical features: Constriction rings or bands, Autoamputation of digits or limbs ; Syndactyly; Abdominal wall defects, visceral protrusions; Craniofacial anomalies

Question 5

At what week does fetes start producing surfactant?

Answer 5

week 20. pneumocytes develop at week 20

Question 6

At what week, respiration is possible?

Answer 6

Week 25

Question 7

Error at which stage leads to tracheoesophageal fistula?

Answer 7

embryonic stage week 4 to 7