L22 Development of Kidneys (INCOMPLETE)

Question 1

The tissues that are destined to become permanent kidneys are preceded by embryonic structures, most of which degenerate and atrophy before birth. What are the three stages in the development of these embryonic structures?

Answer 1

Pronephros
Mesonephros
Metanephros

Question 2

From which embryonic layer do the kidneys form?

Answer 2

Intermediate mesoderm.

This area of the mesoderm lies between the paraxial mesoderm and the lateral plate.

Question 3

Which of the following is associated with cells that originate in the intermediate mesoderm and structures known as cervical nephrotomes?

A) Pronephros
B) Mesonephros
C) Metanephros

Answer 3

A) Pronephros

Question 4

In pronephric stage of renal development, how many pairs of nephrotomes develop?

Answer 4

5-7

Question 5

What is the function of nephrotomes?

Answer 5

They are non-functional (vestigial). They form early in week 4 and disappear by the end of week 4

Question 6

What is a nephrotome?

Answer 6

A hollow ball of epithelial cells that forms during pronephros stage of renal develop.

5-7 pairs of nephrotomes form and then disappear in week 4 of gestation.

Question 7

Mesonephros starts when?

Answer 7

Early in week 4 of gestation

Question 8

How many pairs of mesonephric tubules are formed during mesonephros?

Answer 8

40 pairs are produced craniocaudally (from top to bottom), but reduces to 30 and eventually only 20 are left after cranial regression.

Question 9

What are Wolffian ducts?

Answer 9

Mesonephric ducts that first appear in thoracic region in week 4 of gestation.

Question 10

What is bifid ureter?

Answer 10

Premature bifurcation of the ureteric bud

Question 11

What causes ectopic ureter?

Answer 11

Production of two ureteric buds from a single mesonephric duct.

In females it can cause additional and constant urine drainage via the vagina or vulva vestibule

Question 12

What causes urachal sinus?

Answer 12

Drainage of urine through the umbilicus

Question 13

What causes urachal sinus?

Answer 13

Caused by fusion of the lower poles of the metanephric blastemas prior to ascent

Question 14

What causes urachal cyst?

Answer 14

Sinus remaining from allantois during development; cyst occurs between umbilicus and bladder

Question 15

What causes pancake kidney?

Answer 15

Caused by fusion of both poles of the contralateral kidney primordia

Question 16

What is renal hypoplasia?

Answer 16

Small kidneys

Question 17

What is renal agenesis?

Answer 17

One kidney fails to develop due to absence of ureteric bud