Embryology

Question 1

Which structure develops into the kidney and renal duct?

Answer 1

The metanephros

Question 2

At what age foes the anterior fontanelle close

At what age foes the posterior fontanelle close

Answer 2

Anterior - 18 months

Posterior - 2 months

Question 3

In foetal circulation, umbilical venous blood passes through which structure before entering the inferior vena cava?

Answer 3

Ductus venosus

Question 4

A bicornuate uterus is the result of failure of which embryonic structure to correctly fuse?

Answer 4

Paramesonephric duct

Question 5

How many cells are there on Day 3?

Answer 5

Day 3 - Morula - 12 to 16 cells

Day 4/5 - Blastocyst
Day 6 - Implantation

Question 6

At what age are there the maximum number of ova?

Answer 6

20 weeks gestation

Question 7

What drug is used to close a symptomatic ductus arteriosus?

Answer 7

Indomethacin
(a prostaglandin antagonist)

Question 8

The renal tubules develop from

Answer 8

Metanephros

Question 9

Uterus didelphus results from the failure of fusion of which structure

Answer 9

Paramesonephric duct

Question 10

On fetal US abdomen shows defect in abdominal wall with intestine protruding out covered with layer

Answer 10

Omphalocele

O - omphalocele
In a bubble ‘O’

Question 11

What is the embryonic origin of the trigone of urinary bladder?

Answer 11

Mesoderm
(caudal end of the mesonephric duct)

The rest of the bladder is from the endoderm

Question 12

What does the genital ridge give rise to in the female foetus?

Answer 12

Ovary

Question 13

What is the name of a placenta where the umbilical cord is attached to the margin?

Answer 13

Battledore placenta

Question 14

The round ligament of the uterus develop From which embryonic structure?

Answer 14

Gubernaculum

Question 15

What is the embryological origin of Gartners duct cyst?

Answer 15

Mesonephric duct

Question 16

Ductus venosus is completely obliterated after birth to form what adult structure?

Answer 16

Ligamentum venosum

Ductus venosus –> ligamentum venosum

Question 17

Which cells produce mullerian-inhibiting substance in fetal testis?

Answer 17

Sertoli cells

Question 18

Where in the developing embryo do primordial germ cells originate?

Answer 18

Yolk Sac Endothelium

Question 19

The greater omentum is derived from which of the following embryonic structures? Be specific

Answer 19

Dorsal mesogastrium

Question 20

In Horseshoe Kidney what structure prevents the kidney from ascending from pelvis to abdomen?

Answer 20

Inferior mesenteric artery
(the arterial supply of the hind gut)

Question 21

Primary mechanism of shunting blood away from the pulmonary circulation

Answer 21

Ductus arteriosus

Question 22

Gonads are derived from which part of which embryonic layer?

Answer 22

Intermediate mesoderm

Question 23

The ureteric bud is derived from which of the following structures ?

Answer 23

Mesonephric duct

Mesonephros –> ureteric bud –>
Ureter, renal pelvis, calyx, collecting duct

Metanephros–>
Glomerulus, capsule, PCT/Henle/DCT

Question 24

Allantois embryonic origin

Answer 24

Endoderm

Question 25

CNS is the most affected during teratogenesis. What is the first sensation developed in the fetus?

Answer 25

Touch

Question 26

Gastrulation is process of

Answer 26

Development of three germ layers

Question 27

In fetal circulation which structure caryy oxygenated blood from right atrium to left atrium?

Answer 27

Foramen ovale

Question 28

Central lump pointed to by arrow

Answer 28

Inner cell mass

Question 29

When does adult haemoglobin start being produced?

Answer 29

At birth

Question 30

Embryonic origin of oocytes

Answer 30

Primordial germ cell

Question 31

Embryological origin of appendix testis

Answer 31

Paramesonephric duct

Question 32

What do the umbilical arteries become? What does the umbilical vein become?

Answer 32

Umbilical arteries - medial umbilical ligaments Umbilical vein - ligamentum teres

Question 33

Embryological origin of the lower 2/3 of the vagina

Answer 33

Endoderm and urogenital sinus Remember endoderm also makes the cloaca

Question 34

Embryological origin of the bladder

Answer 34

Endoderm: Cloaca -->urogenital sinus --> bladder

Question 35

When do the primordial germ cells migrate from the yolk sac to the mesoderm? /Where are germ cells at week 4

Answer 35

Week 5 Yolk sac

Question 36

What is the main Hb in fetus 32 weeks?

Answer 36

HbF

Question 37

What structures form from the 2nd pharyngeal arch?

Answer 37

Muscles - muscles of facial expression Nerve - Facial nerve Skeletal - stapes, temporal styloid process, hyoid, stylohyoid

Question 38

What two structures does the ductus venosus join?

Answer 38

umbilical vein IVC

Question 39

The ductus arteriosus connects which two structures?

Answer 39

Aorta and pulmonary artery

Question 40

Which structure establishes bilateral symmetry, determines the site of gastrulation, and initiates germ layer formation?

Answer 40

Primitive streak

Question 41

What day does the neural tube close?

Answer 41

30 (4 weeks)

Question 42

What structures does the vitilline duct connect?

Answer 42

Yolk sac and midgut

Question 43

What is the source of cholesterol in a term foetus?

Answer 43

Foetal liver

Question 44

At what week does the foetus begin to produce urine? At what week does foetal urine become the major contributor to amniotic fluid?

Answer 44

Week 10 Week 18

Question 45

At what cell stage do monochorionic diamniotic twins split?

Answer 45

4 - 8 days - early blastocyst Morula day 3 Blastocyst day 4-5 Implantation day 6

Question 46

When does the anterior pituitary begin to develop?

Answer 46

6-7 weeks (?)

Question 47

What structure does ligamentum arteriosus come from?

Answer 47

Ductus arteriosus