Embryology Part 2 Flashcards
Summarise the development of limbs
Upper and lower limb buds form (3-4th week)
They develop into protrusions (7th week)
Upper limbs rotate outwards
Lower limbs rotate medially resulting in a helical pattern of lower extremity dermatomes
What do you call loss of digits?
Oligodactyly
Which stage of pregnancy did thalidomide affect?
First trimester - affected many organs, particularly upper limb development
Why is thalidomide still used despite its known complications?
Useful in:
Cancer
Leprosy
What is the likely mechanism of action of thalidomide?
Damages developing blood vessels (upper limb blood vessels more sensitive)
Deprives adjacent cells of nutrients and prevents growth
Why is the timing of administration particularly pertinent with thalidomide?
Severe morning sickness occurs around 8th week
Limb development also occurs around this time
How common is kidney development problems?
Relatively common, and humans can survive with only one kidney
What name is given to the immature form of a kidney?
Pronephros
What do you call a kidney it its intermediate phase of maturation?
Mesonephros
What name is given to the most mature form of a kidney?
Metanephros
What is the key thing about pronephros and mesonephros?
They degenerate and DO NOT give rise to the metanephros; this develops independently
During which week does the pronephros develop?
Early 4th week
Summarise the main stages of human kidney development i.e. when the various stages develop and degenerate
Early 4th week - pronephros development
6th week - degeneration of pronephros and development of mesonephros
8th week - degeneration of mesonephros and differentiation of metanephric tissue
Describe the movement of the kidney during development and what aids it.
Metanephros starts off caudally, and moves rostrally via extension of the ureter.
What happens to renal arteries as the kidney moves upwards?
New connections with developing arterial system formed as kidneys move, therefore renal arteries break down and re-form
State three abnormalities of the kidney that can arise during development
Horseshoe kidney (fusion of distal end of two kidneys) Retainment of one kidney in pelvis Retention of an extra artery e.g. underneath ureter-> obstruction of ureter -> enlargement of renal pelvis