Embryology

Question 1

When does the gestational time frame begin

Answer 1

Starts after the beginning of the last menstrual cycle

Question 2

How is embryological development measured

Answer 2

Carnegie stages

Question 3

What are blastocysts, embryos and foetuses

Answer 3

Blastocyst - epiblast and hypoblast present at 9 days and is around 0.1cm wide
Embryo - small developing conceptus at 5-6 weeks and is around 1cm wide
- Can include everything from day 1 onwards and includes placenta as well as baby
Foetus - developing conceptus at 3 months and is now around 7cm wide

Question 4

What is the conceptus

Answer 4

Anything derived from a fertilised egg

Question 5

What 4 simple processes are repeated to achieve embryology

Answer 5

• Proliferate
• Move
• Differentiate
• Cell loss

Question 6

What are the different signalling methods used in embryo development

Answer 6

Paracrine - to adjacent cells
Autocrine - to oneself
Endocrine - not much vasculature in embryo so doesnt occur much

Question 7

What is concentration signalling

Answer 7

The strongest signals are received by cells located closest to the source of the signalling molecules

Question 8

What does embryology depend on

Answer 8

• Gradients of factors
• Combinations of factors
• Temporal changes in factors or responses to them