Dr. Indran 10 Development of Urinary System

Question 1

The urogenital system is derived from a longitudinal strip of the_______, the urogenital ridge

The urogenital ridge divides into the ____ and the _____

Answer 1

intermediate mesoderm

Nephrogenic cord:

Forms the urinary system

Gonadal ridge:

Forms the gonads

Question 2

What are the 3 nephric ducts?

8.6.1

Answer 2

3 Nephric Systems:

Pronephros

¤Develops in the cervical region

Mesonephros

¤Extends from the upper thoracic region to the third lumbar level

Metanephros

¤Develops in the sacral region

Question 3

_______ Forms at the beginning of 4th week from intermediate mesoderm in the cervical region

7 to 10 solid tubules

All degenerate by the end of 4th week

Answer 3

Pronephros

Question 4

________

First appears as a solid longitudinal rod in the i_ntermediate mesoderm_ in the pronephric region

Answer 4

Mesonephric Duct

These rods develop in a caudal direction, forming a duct:

¤Mesonephric duct (Wolffian duct or nephric duct)

¤As the ducts grow into the lower lumbar region, they diverge from the intermediate mesodermal mesenchyme and grow toward and fuse with the ventrolateral walls of the cloaca

The caudal end of each mesonephric duct induces the formation of a ureteric bud

Question 5

As the mesonephric ducts develop and extend caudally, they induce the formation of ________ in the intermediate mesoderm

Answer 5

mesonephric buds

Form mesonephric tubules from the upper thoracic region to the third lumbar level

Caudal mesonephric tubules differentiate into excretory units:

¤Medial end of the tubule forms a cup-shaped sac:

Bowman’s capsule:

Bowmans’s capsule wraps around a knot of capillaries:

Glomerulus:

Together they form the renal corpuscle

Question 6

¨Mesonephric _______ are functional until the 10th week and produce urine

Answer 6

excretory units

The mesonephric duct forms the genital outflow duct system in the males

In females they disappear

Question 7

Metanephroi are the definitive kidneys

Composed of two functional components:

Answer 7

Collecting portion

Derived from the ureteric bud that forms from the mesonephric duct

Excretory portion

Derived from the metanephric blastema

Question 8

Development of the metanephros involves what 5 things?

8.6.1

Answer 8

Cell condensation

Mesenchymal-to-epithelial conversion

Epithelial tube formation and elongation

Angiogenesis

Specification and differentiation of numerous specialized cell types

Question 9

A _______ sprouts from the caudal portion of each mesonephric duct around day twenty-eight

Answer 9

ureteric bud

By day thirty-two, each ureteric bud penetrates a portion of the sacral intermediate mesoderm called the metanephric mesenchyme/metanepric blastema, and the bud begins to bifurcate

As the ureteric bud branches, each new growing ureteric tip acquires a cap-like aggregate of metanephric mesenchymal tissue:

Cap mesenchyme

Question 10

Structures Forming the Collecting and Excretory Portions of the Metanephros

Answer 10

Question 11

Development of the ureteric bud and the formation of the collecting duct system

Answer 11

8.6.1

Question 12

Development of the ureteric bud and the formation of the collecting duct system cont..

Answer 12

8.6.1

Question 13

Development of the Excretory Portion from Metanephric Mesoderm/Metanephric blastema

Answer 13

8.6.1

Question 14

Development of the Excretory Portion from Metanephric Mesoderm/blastema cont…

8.6.1

Answer 14

8.6.1

Question 15

True or False: The definitive renal architecture of the metanephros is apparent by the tenth week

8.6.1

Answer 15

8.6.1

Question 16

Summary of Kidney Development

Answer 16

Question 17

Summary of Kidney Development cont..

Answer 17

8.6.1

Question 18

Explain the relocation of kidneys

Answer 18

¤during the relative ascent, the kidneys rotate 90, causing the hilum, which initially faces ventrally to finally face medially

he fetal metanephros is located at vertebral level S1-S2 (A)

he definitive adult kidney is located at vertebral level T12- L3 (B)

¤The change in location results from a di_sproportionate growth of the embryo caudal to the metanephros_

Question 19

Arteries formed during the ascent may persist and are called _______:

¤Supernumerary arteries are end arteries

¤Therefore, any damage to them will result in necrosis of kidney parenchyma

Answer 19

supernumerary arteries

¨During the relative ascent of the kidneys, they will receive their blood supply from arteries at progressively higher levels until the definitive renal arteries develop at L2

Question 20

Development of bladder and urethra

8.6.1

Answer 20

8.6.1

Question 21

What are the three portions of the urogenital sinus?

8.6.1

Answer 21

8.6.1

Question 22

Derivatives of different parts of urogenital sinus

Answer 22

8.6.1

Question 23

Explain the development of trigone

Answer 23

Question 24

Development of Trigone cont..

Answer 24

8.6.1

Question 25

Summary of the development of urinary bladder

8.6.1

Answer 25

With time, mesodermal lining of trigone is replaced by endodermal epithelium, so that bladder is completely lined with endodermal epithelium finally

8.6.1

Question 26

Formation of median umbilical ligament

8.6.1

Answer 26

8.6.1

Question 27

_______

¤Lumen of allantois persists

¤Urine from umbilicus

_______

¤Local area of allantois persists

¤Secretory activity of its lining results in a cystic dilation

_______

¤When lumen in upper part of allantois persists

Answer 27

Urachal fistula

Urachal cyst

Urachal sinus

Question 28

Development of Urethra

Answer 28

Question 29

Summary of Male Urethra