27. Development of urinary tract

Question 1

what is the functional unit of the kidney?

Answer 1

nephron

Question 2

What are the 3 kidney systems in the embryo?

Answer 2

pronephros, mesonephros, metanephros

Question 3

Does the pronephros function in humans?

Answer 3

No.

Question 4

How do the 3 kidney systems develop in relation to eachother?

Answer 4

• 3 systems develop sequentially

* Disappearance of one system marks the onset of development of the next developmental stage

Question 5

Where does the pronephros appear?

Answer 5

in the cervical region

Question 6

Why is the pronephric duct important?

Answer 6

It extends from the cervical regions to the cloaca and drives the development of the next developmental stage

Question 7

How does the pronephric duct drive further development?

Answer 7

Induces nearby intermediate mesoderm in the thoracolumbar region to form mesonephric tubules.

Question 8

What is the mesonephric duct a continuation of?

Answer 8

Pronephric duct.

Question 9

what is the urogenital ridge?

Answer 9

Region of intermediate mesoderm giving rise to both the embryonic kidney and the gonad

Question 10

Where do mesonephric tubules develop?

Answer 10

caudal to the pronephric region

Question 11

What contributes to the embryonic kidney?`

Answer 11

Mesonephric duct and mesonephric tubules

Question 12

What is a functional limit of the mesonephros that doesn’t allow it to be useful after birth?

Answer 12

Has no water conserving capabilities.

Question 13

How does mesonephros initiate development of definitive kidney?

Answer 13

Mesonephric duct sprouts ureteric bud.

Question 14

What is the function of the ureteric bud?

Answer 14

Induces development of the true kidney (metanephros) from the undifferentiated intermediate mesoderm found caudal to the mesonephros

Question 15

What is the tissue that the true kidney develops from called?

Answer 15

Metanephros blastema

Question 16

What is the other function of mesonephric duct?

Answer 16

role in the development of the reproductive system in the male

Question 17

What is the collecting system of kidney developed from?

Answer 17

Ureteric bud.

Question 18

What does the collecting system of kidney consist of?

Answer 18

minor calcyx, major calyx, renal pelvis, ureter

Question 19

What does the excretory component of kidney consist of ?

Answer 19

cortex, renal pyramid

Question 20

What is the excretory system developed from?

Answer 20

Metanephric blastema (under influence of ureteric bud)

Question 21

What is the metanephric blastema?

Answer 21

Undifferentiated intermediate mesoderm

Question 22

Describe Development of the renal functional unit

Answer 22

• ureteric bud contacts metanephric blastema
• bud expands & branches forming the collecting system
• metanephric blastema becomes the excretory component

Question 23

Where do the kidneys develop and where doe they move to?

Answer 23

• The metanephric kidney first appears in the pelvic region

* Undergoes an apparent caudal to cranial shift

Question 24

What do the kidneys cross during their ascent?

Answer 24

Arterial fork formed by vessels returning blood from the fetus to the placenta

Question 25

How do the renal vessels follow the kidney during its ascent?

Answer 25

New vessels form from the aorta as the kidneys move up. Old ones are obliterated.

Question 26

What are renal accessory vessels and what percent of the population are they present in?

Answer 26

Renal vessels that do not get obliterated during ascent of the kindeys. 25%

Question 27

What is renal agenesis?

Answer 27

absence of one or both kidneys

Question 28

How does renal agenesis occur?

Answer 28

Failure of ureteric bud to interact with intermediate mesoderm

Question 29

What could go wrong with development of ureters or kidneys?

Answer 29

* renal agenesis * Migration goes awry * Duplication defects * Ectopic ureter * Cystic disease

Question 30

what are the structural abnomalies related to mifgration problems of the kidney?

Answer 30

pelvic kidney | horseshoe kidney

Question 31

What is a horseshoe kidney?

Answer 31

inferior poles of both kidneys fuse; during the ascent from the pelvis in development, the horseshoe kidney gets trapped under the inferior mesenteric artery

Question 32

Describe how Duplication defects & ectopic ureteral orifices occur?

Answer 32

Splitting of the ureteric bud • Partial or complete • Symptomatic consequence is ectopic ureteral opening

Question 33

What is the common caudal opening that , the reproductive tract, urinary tract and GI tract share?

Answer 33

cloaca

Question 34

What closes the cloaca to the outside?

Answer 34

* Closed to the outside by the cloacal membrane | * no mesoderm

Question 35

What structure connects the urogenital sinus with the umbilicus?

Answer 35

Urachus

Question 36

What is the function of the urachus?

Answer 36

Canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord

Question 37

What does the urachus become when it closes?

Answer 37

Median umbilical ligament

Question 38

What creates the urogenital sinus?

Answer 38

Urorecal septum which separates the cloaca into the urogenital sinus and the anal canal

Question 39

What does the urogenital sinus differentiate to form

Answer 39

Majority forms the bladder. Inferior part develops into the urethra

Question 40

How is the trigone of the bladder formed?

Answer 40

As the bladder develops from the urogenital sinus, it absorbs the caudal parts of the mesonephric ducts, becoming the trigone of the bladder. The ureters, which have formed as outgrowths of the mesonephric ducts, enter the bladder at the base of the trigone

Question 41

What does the female urethra develop from?

Answer 41

Pelvic part of urogential sinus

Question 42

What does the male urethra develop from?

Answer 42

Pelvic part of urigenital sinus forms the pre-prostatic, prostatic and membranous urethra. Spongy urethra develops from fusion of genital folds.

Question 43

Describe what happens to urogenital sinus in females?

Answer 43

* mesonephric ducts (MD) reach urogenital sinus (UGS) * ureteric bud (UB) sprouts from MD, MD begin to regress; * MD regression continues, ureteric bud opens into UGS

Question 44

Describe what happens to urogenital sinus in males?

Answer 44

* mesonephric ducts (MD) reach urogenital sinus(UGS) * ureteric bud (UB) sprouts from MD * smooth musculature begins to appear; UBs & MDs make independent openings in UGS * prostate & prostatic urethra formed

Question 45

What is hypospadia?

Answer 45

* Defect in fusion of urethral folds | * Urethra opens onto the ventral surface rather than at the end of the glans

Question 46

What are the 4 parts that the male urethra is divided into?

Answer 46

Pre-prostatic • Prostatic • Membranous • Spongy