Cell development

Question 1

What are the (named) stages of embryonic development?

Answer 1

Unfertilized egg
Zygote (fertilized egg)
Morula
Blastocyst

Question 2

What is cleavage?

Answer 2

The first round of divisions that occur in a fertilized egg.

Question 3

What are the three germ layers?

Answer 3

Endoderm (inner)
Mesoderm (middle)
Ectoderm (outer)

Question 4

What does the ectoderm give rise to?

Answer 4

Nervous system (CNS and PNS)
Epidermis (Skin)

Question 5

What does the endoderm give rise to?

Answer 5

Lungs
Gut
Pancreas
Liver

Question 6

What does the mesoderm give rise to?

Answer 6

Kidneys
Trunk skeleton
Muscle
Haemopoetic system (Heart and blood)
Dermis (Layer below the skin)

Question 7

What are the model organisms used to study development?

Answer 7

Rats/Mice
Frogs
Flies
Flatworms
Chicks
Zebrafish

Question 8

Pax6…

Answer 8

.

Question 9

What percentage of live born children have a congenital defect?

Answer 9

3-4%

Question 10

What are the advantages to using mice to study development?

Answer 10

.

Question 11

What are the advantages to using zebrafish to study development?

Answer 11

.

Question 12

What are the advantages to using chicken to study development?

Answer 12

.

Question 13

What are the advantages to using frogs to study development?

Answer 13

.

Question 14

What are the advantages to using flies to study development?

Answer 14

.

Question 15

What does the blastocyst consist of?

Answer 15

Inner cell mass which goes on to form the germ layer

Trophoblast which goes on to form the placenta

Question 16

When is the organ system developed?

Answer 16

Between 3-8 weeks after fertilization

Question 17

Why is the CNS underdeveloped at birth for humans?

Answer 17

Childbirth would be difficult if at birth the child was more developed.

Question 18

When is an embryo most susceptible to birth defects?

Answer 18

Between 3-8 weeks with the 5th week being the ‘riskiest’ week.

Question 19

What is a teratogen?

Answer 19

A factor which cause malformation of an embryo.

Question 20

What is ‘transposition of the great blood vessels’?

How is it fixed?

Answer 20

It is when the aorta and pulmonary artery positions are are switched causing cyanotic heart disease in newborns. (cyanosis is a blue discolouration of the skin caused by deoxygenation)
To rectify this malformation, there is immediate heart surgery performed on the fetus to switch the great blood vessels to their proper positions.

Question 21

What is ankyloglossia?

Answer 21

Congenital malformation of the tongue where the tip is attached to the floor of the mouth .

Question 22

What does congenital mean?

Answer 22

Present at birth.

Question 23

What is cleft palate?

Answer 23

Congenital malformation of the top of the lip where an opening or split is present due to tissues of this region not fusing together properly during prenatal development.

Question 24

What is coloboma?

Answer 24

Congenital malformation where there is a hole in a part of the eye.

Question 25

What is polydactyly?

Answer 25

Congenital malformation where additional fingers or toe have formed.

Question 26

What is Down’s syndrome?

Answer 26

It is a congenital chromosomal defect where there is an extra copy of chromosome 21 causing a whole host of developmental defects. This includes:
Growth failure
Mental retardation and learning disabilities
Motor and sensory ability delay in development

It affects 1 in 1000 babies

Question 27

What is cleidocranial dysostosis?

Answer 27

Congenital condition that primarily affects the bones and teeth. Severity ranges, but a common symptom is underdeveloped or absent collarbones.

Question 28

What is thalidomide and what is its significance?

Answer 28

It is a medical drug that was used to ‘cure’ morning sickness during pregnancy. It was launched in 1957 and affected 12,000 children so was subsequently taken off market in 1961. It led to new FDA guidelines for testing drugs.

It is still used today as a medical drug to treat AIDS, leprosy and some cancers, but not for morning sickness

Question 29

What are symptoms of fetal alcohol syndrome?

Answer 29

There is a wide range of symptoms between patients

Microcephaly (small head)
Low nasal bridge
Short nose
Epicanthal folds
Flat midface
Thin upper lip
Micrognathia (small jaw)

Question 30

What is ‘Zika Virus’ and what are its symptoms?

Answer 30

A virus transmitted by mosquitoes.
Adults who are affected by the disease may have mild symptoms (fevers, rashes, headaches and muscle and joint pains) with symptoms lasting for 2-7 days, with some patients not even exhibiting symptoms.

Zika virus infection during pregnancy can cause infants to be born with microcephaly and other congenital malformations, known as congenital Zika syndrome.

Question 31

NTDs…

Answer 31

.

Question 32

What can ectodermal defects lead to?

Answer 32

Defects in the...
Hair
Sweat glands
Teeth
Mammary gland (decreased milk production for females)

Question 33

What can mesodermal defects lead to?

Answer 33

Defects in the…
Skeleton
Cartilage
Number of fingers and toes

Question 34

What can endodermal defects lead to?

Answer 34

Defects in the…
Lungs
Esophagus
Gut

Question 35

Lecture capture for the last few slides of L20

Answer 35

.

Question 36

What are neural crest cells?

Answer 36

They are multipotent stem cells in the skin that can differentiate to neurons, pigment cells, Schwann cells and smooth cells