L5: Defects in Development

Question 1

Define morula

Answer 1

Embryo at early stage of embryonic development

Question 2

Define blastocyst

Answer 2

Cluster of dividing cells made by fertilised egg (inner cell mass)

Question 3

What is the lining that lines the blastocyst?

Answer 3

Trophoblast

Question 4

3 germ layers

Answer 4

1) ectoderm
2) mesoderm
3) endoderm

Question 5

When does the 3 germ layers arise from?

Answer 5

Gastrulation

Question 6

What does ectoderm form?

Answer 6

• Skin
• Nervous system

Question 7

What does mesoderm form?

Answer 7

• Muscle
  
  • Skeleton
  • Kidneys
  • Reproductive system

Question 8

What does endoderm form?

Answer 8

• Endocrine glands
• Lungs
• Liver
• Digestive tract

Question 9

4th type of germ layer

Answer 9

The Neural Crest

Question 10

Where do cells leave in the neural crest?

Answer 10

Neural tube

Question 11

How do cells leave the neural tube?

Answer 11

Densely packed cell in the beginning

In order for cells to migrate out, they have to change their phenotype, becoming loosely packed cell

Question 12

What do cells that leave the neural crest make?

Answer 12

1) Sensory neurons
2) Autonomic neurons
3) Enteric neurons
4) Schwann cells
5) Smooth muscle

Question 13

Define angiogenesis

Answer 13

Process of new capillaries forming from pre-existing blood vessels

Question 14

When does the heart already start beating ?

Answer 14

3 weeks

Question 15

Are the 3 germ layers unipotent, multipotent or pluripotent?

Answer 15

Multipotent

Differentiate into multiple cell types

Question 16

How is the multipotent neural crest generated?

Answer 16

Epithelial-mesenchymal transformation from the neuroectoderm

Question 17

Which weeks does most organs develop within the embryonic period?

Answer 17

Weeks 3-8

Question 18

Is inner cell mass unipotent, multipotent or pluripotent or totipotent?

Answer 18

Totipotent?

Give rise to any cell type

Question 19

Is inner cell mass pluripotent, multipotent or unipotent?

Answer 19

Pluripotent

Give rise to several different cell types

Question 20

2 major defects in development

Answer 20

1) Transposition of the great blood vessels

2) Diaphragmatic hernia

Question 21

Minor birth defects

Answer 21

Tongue tie
Bilaterial cleft lip

Question 22

Causes of human embryonic malformations?

Answer 22

• Unknown
• Genetic factors
• Environmental factors
• Inheritance

Question 23

Example of chromosomal defects

Answer 23

Down’s syndrome

Question 24

Define TORCH conditions

Answer 24

1. Toxoplasma parasite
2. Other viruses
3. Rubella virus
4. Cytomegalovirus
5. Herpes simplex virus

Question 25

2 factors that can cause birth defects

Answer 25

• Gene mutations
• Chromosomal abnormalities

Question 26

When is the embryo/fetus more vulnerable to teratogens?

Answer 26

During embryonic period (week 5)

Question 27

Define teratogen

Answer 27

Any agent that causes an abnormality following fetal exposure during pregnancy (alcohol exposure)