Embryology

Question 1

What are some of the processes which occur in the FIRST WEEK during embryo formation?

Answer 1

Ovulation - Ovary releases egg

Fertilisation - sperm and egg fuse to produce zygote

Implantation - zygote attaches to uterus

Question 2

What is a morula?

Answer 2

A SOLID mass of cells, usually achieved after 4-6 days after fertilisation

Question 3

What is a blastocyst?

Answer 3

A HOLLOW ball of cells, usually achieved after 6-10 days after fertilisation

Question 4

What are the 3 basic germ cell layers?

Answer 4

Endoderm - inner layer
Ectoderm - outer layer
Mesoderm - middle layer

Question 5

Where do germ cells originate from?

Answer 5

Primitive streak

Question 6

What is one of the first organs to form?

Answer 6

The CNS

Question 7

What weeks is the does embryo development occur?

Answer 7

Weeks 4-7

Question 8

What weeks does fetus development occur?

Answer 8

Weeks 9-20

Question 9

What organs do ECTODERM cells usually contribute to?

Answer 9

• Skin
• Mucous membranes of mouth
• Brain, Spinal cord
• Tooth enamel

Question 10

What organs do MESODERM cells usually contribute to?

Answer 10

• Most connective tissues (dermis, tendons, cartilage, bone)
• Muscles
• Blood vessels
• Kidney and urinary system
• Reproductive systems
• Serous membranes

Question 11

What organs do ENDODERM cells usually contribute to?

Answer 11

• Alimentary canal (entire length)

- Respiratory system

Question 12

What is the ECTOMESENCHYME?

Answer 12

Another layer of cells (important)

Gives rise to:

• Peripheral nervous system
• Dentine, cementum, pulp, PDL formation, jaw bones