Embryology revision

Question 1

what are the 4 stages of embryological development in general, and list the time period for each stage.

Answer 1

1. Conception (1 cell)
2. 3 germ layers 1-3 weeks
3. embryo 3-10weeks
4. Fetus 10-40weeks

Question 2

at what stage during gestation do most surgical abnormalities arise?

Answer 2

during the embryo phase from 3-10weeks

Question 3

from which germ layer is the neural tube derived?

Answer 3

ectoderm

Question 4

when do the testes normally descend in a boy?

Answer 4

about 7 months during gestation

Question 5

from which embryological structure does the epididymis, vas deferens and seminal vesicle arise?

Answer 5

wolffian duct

Question 6

from which embryological structure does the uterus, fallopian tubes and upper vagina?

Answer 6

mullarian duct

Question 7

which key gene is required for testicular development?

Answer 7

SRY gene on the Y chromosome

Question 8

at what embryological stage are female and male embryos have the same undifferentiated external genitalia?

Answer 8

up until 8 weeks gestation

Question 9

what is a Meckel’s diverticulum?

Answer 9

a true congenital diverticulum containing all three layers of the bowel wall. It is the remnant of the omphalomesenteric duct or yolk sac duct of the embryo, and is located in the distal ileum.