Embryology

Question 1

1. The average length of the human gestational period (from fertilization to childbirth) is:

Answer 1

38 weeks

Question 2

Fertilisation age is how many weeks less than the menstrual age?

Answer 2

2 weeks

Question 3

The ovum undergoes implantation at the stage of what?

Answer 3

Blastocyst

Question 4

Which process converts the disc into the trilaminar embryo?

Answer 4

gastrulation

Question 5

Folding of the emryo is what direction?

Answer 5

craniocaudal and lateral

Question 6

cerebral calcifications will be common in what ?

Answer 6

cytomegalovirus

Question 7

The structure that induces the ectoderm to thicken and form the neural plate is what?

Answer 7

Notochord

Question 8

Failure of the anterior neuropore to fuse causes what?

Answer 8

anencephaly

Question 9

what week has the highest risk of birth defects occuring?

Answer 9

Week 5

Question 10

TORCH stands for what?

Answer 10

Toxoplasmosis
Other (hepatitis B, Syphilis)
Rubella (German measles)
Cytomegalovirus (CMV)
Herpes simplex virus (HSV)

Cross placenta

Question 11

measles during prgnancy can cause?

Answer 11

Cataracts and hearing loss (small brain)

Question 12

Smooth pholtrium and thin upper lip could be what in a newborn?

Answer 12

foetal alcohol syndrome

Question 13

what is the morulla stage?

Answer 13

16-32 cells inner is embryoblast outer is placenta (trophoblast)

Question 14

Implantation day what?

Answer 14

5-6

Question 15

Epiblast forms which surface?

Answer 15

Dorsal

Question 16

Hypoblast forms?

Answer 16

Ventral (hypoventilate)

Question 17

What erodes wall of the maternal capillaries?

Answer 17

syncitiotrophoblast (far back)

Question 18

between primary yolk sac and? cytotrophoblast is what

Answer 18

extraembryonoic mesoderm

Question 19

Cavity formed in the extraembryonic mesoderm is what?

Answer 19

Chorionic cavity

Question 20

by end of week 2 the embyo is suspended via what

Answer 20

connecting stalk forms part of umbilical cord

Question 21

What secretes HCG?

Answer 21

synchitiotrophoblast

Question 22

What is a hydatoform mole?

Answer 22

Development of trophoblast with no embryo (fertilising an empty egg)

Question 23

Paternal gees favor what

Answer 23

formation of trophoblast at expense of embryo

Question 24

Epiblast cells move towards primitive streak and insert into hypoblast to form what?

Answer 24

definitive endoderm

Question 25

epiblast cells move down primitive streak to form what in the middle?

Answer 25

mesoderm

Question 26

What does the paraxial mesoderm divide into on day 20?

Answer 26

somites cranial to caudal predicts age of embryo

Question 27

abnormal gastrulation can lead to what?

Answer 27

mermaid syndrome

Question 28

remnants of primitive streak can cause what?

Answer 28

Sacrococygeal tumour

Question 29

what is the notochord?

Answer 29

hollow tube

Question 30

notochord induces what?

Answer 30

neuralation overlying ectoderm thickens = neural plate

Question 31

remnants of the notochord persist as what?

Answer 31

spongy nucleus pulposus of vertebrae discs

Question 32

tuft of hair at back can be what?

Answer 32

spinabifida occulta

Question 33

meningocele is what?

Answer 33

sac that develops outside of spine but is cpovered

Question 34

myelomeningocele is what

Answer 34

sac outside the spinal chord bigger and has spinal chord in

Question 35

lateral edges of neural plate elevate to make what?

Answer 35

neural folds

Question 36

4th germ layer =

Answer 36

neural crest cells

Question 37

neurofibramatosis as a disease cause by what?

Answer 37

non supression of neural crest cells

Question 38

4th week embryo fold how?

Answer 38

craniocausdal and lateral

Question 39

ectopia cordis is what?

Answer 39

heart outside body, lateral fold do not fuse in thoracic

Question 40

Ventral body wall defects ?

Answer 40

lateral fusing doesnt happen causing gastroschisis