SM_179b: UG Development

Question 1

Describe the male genital anatomy

Answer 1

Male genital anatomy

Question 2

Describe internal female genital anatomy

Answer 2

Internal female genital anatomy

Question 3

Labia major is ____

Answer 3

Labia major is folds of the superficial body wall

Question 4

Labia minor flanks the ____

Answer 4

Labia minor flanks the vestibule

(space with clitoris and openings of vagina and urethra)

Question 5

Both sexes start with ____ primordia

Answer 5

Both sexes start with the same primordia

• Mesonephric duct -> male structures
• Paramesonephric duct -> female structures

Question 6

____ becomes the male genital structures

Answer 6

Mesonephric duct becomes the male genital structures

Question 7

____ becomes the female genital structures

Answer 7

Paramesonephric duct becomes the female genital structures

Question 8

Describe the primordia of the urogenital system

Answer 8

Primordia of the urogenital system

1. Intermediate mesoderm -> kidneys / gonads
2. Splanchnopleure of the hindgut -> bladder / urethra
3. Somatopleure -> genitals

Question 9

Intermediate mesoderm becomes the ____

Answer 9

Intermediate mesoderm becomes the kidneys / gonads

Question 10

Splanchnopleure of the hindgut becomes the ____

Answer 10

Splanchnopleure of the hindgut becomes the bladder / urethra

Question 11

Somatopleure becomes the ____

Answer 11

Somatopleure becomes the genitals

Question 12

With folding of the embryo, the intermediate mesoderm bulges into the peritoneal cavity and forms a ____ with ____ and ____

Answer 12

With folding of the embryo, the intermediate mesoderm bulges into the peritoneal cavity and forms a urogenital ridge with a nephrogenic cord and a gonadal ridge

Question 13

Urogenital ridge consists of ____ and ____

Answer 13

Urogenital ridge consists of nephrogenic cord and gonadal ridge

(develop into kidneys and ovaries / testes)

Question 14

Primordial germs cells migrate from the ____ into the ____

Answer 14

Primordial germs cells migrate from the hindgut into the gonadal ridges

Question 15

Germ cells are surrounded by ____ that project into the ____

Answer 15

Germ cells are surrounded by epithelial sex cords that project into the primitive gonad

Question 16

Paramesonephric (Mullerian) duct develops close to the ____

Answer 16

Paramesonephric (Mullerian) duct develops close to the mesonephric (Wolffian) duct

Question 17

Mesonephric (Wolffian) duct and tubules develop as ____

Answer 17

Mesonephric (Wolffian) duct and tubules develop as condensations of intermediate mesoderm (nephrogenic cord)

Question 18

Mesonephric (Wolffian) duct becomes the ____ and also ____ in the male

Answer 18

Mesonephric (Wolffian) duct becomes the fetal ureter and also changes its function from urinary to genital as it becomes the ductus deferens in the male

Question 19

Paramesonephric (Mullerian) ducts will form ____ and join at their inferior ends to form the ____ and ____

Answer 19

Paramesonephric (Mullerian) ducts will form the uterine tubes and join at their inferior ends to form the uterus and upper vagina

Question 20

Nephrogenic cord forms three sequential kidneys: ____, ____, and ____

Answer 20

Nephrogenic cord forms three sequential kidneys:

1. Pronephros
2. Mesonephros
3. Metanephros

Question 21

First functioning kidney is the ____

Answer 21

First functioning kidney is the mesonephros

Question 22

____ joins the ____ of the first functioning kidney and drains into the cloaca

Answer 22

Mesonephric duct joins the mesonephric tubules of the first functioning kidney and drains into the cloaca

Question 23

____ duct is also called the Wolffian duct and is the first (and temporary ureter)

Answer 23

Mesonephric duct is also called the Wolffian duct and is the first (and temporary ureter)

Question 24

Metanephric diverticulum is also called the ____ and originates from the mesonephric duct

Answer 24

Metanephric diverticulum is also called the ureteric bud and originates from the mesonephric duct

Question 25

Primordia of the metanephros (permanent kidney) are ____ and \_\_\_\_

Answer 25

Primordia of the metanephros (permanent kidney) are 1. Ureteric bud 2. Metanephric mass of intermediate mesoderm

Question 26

Urinary collecting duct and transport system come from the two metanephric primordia: ____ and \_\_\_\_

Answer 26

Urinary collecting duct and transport system come from the two metanephric primordia: * Metanephric mesoderm gives rise to kidney nephrons * Ureteric buds give rise to ureters, renal pelvis, calyces, and collecting tubules in the pyramids

Question 27

\_\_\_\_ gives rise to the kidney nephrons

Answer 27

Metanephric mesoderm gives rise to the kidney nephrons

Question 28

\_\_\_\_ gives rise to the ureters, renal pelvis, calcyes, and collecting tubules in the pyramids

Answer 28

Ureteric buds gives rise to the ureters, renal pelvis, calcyes, and collecting tubules in the pyramids

Question 29

As the kidney ascends, \_\_\_\_

Answer 29

As the kidney ascends, the mesonephros degenerates

Question 30

As the kidney ascends, ____ hook up to it and may persist as \_\_\_\_

Answer 30

As the kidney ascends, sequential arteries hook up to it and may persist as multiple renal arteries

Question 31

\_\_\_\_ is a fusion of the ureteric buds that hook around the inferior mesenteric artery as they ascend

Answer 31

Horseshoe kidney is a fusion of the ureteric buds that hook around the inferior mesenteric artery as they ascend

Question 32

Horseshoe kidney is \_\_\_\_

Answer 32

Horseshoe kidney is a fusion of the ureteric buds that hook around the inferior mesenteric artery as they ascend

Question 33

Describe other anomalies of urogenital tract

Answer 33

Other anomalies of urogenital tract * Mutliple buds resulting in multiple kidneys, renal pelvises, or ureters and failure of buds to ascend

Question 34

\_\_\_\_ divides the cloaca into a rectum and urogenital septum with bladder, pelvic, and phallic parts

Answer 34

Urorectal septum divides the cloaca into a rectum and urogenital septum with bladder, pelvic, and phallic parts

Question 35

Urorectal septum divides the cloaca into \_\_\_\_, \_\_\_\_, and ____ parts

Answer 35

Urorectal septum divides the cloaca into a rectum and urogenital sinus with bladder, pelvic, and phallic parts

Question 36

Improper division of the cloacas results in \_\_\_\_

Answer 36

Improper division of the cloacas results in fistulas (also imperforate anus)

Question 37

Allantois usually becomes a ____ called the \_\_\_\_

Answer 37

Allantois usually becomes a fibrous cord called the urachus * Like any other embryonic tube, it may persist as a cyst, sinus, or fistula

Question 38

Exstrophy of the bladder / cloaca involves ____ and \_\_\_\_, exposing \_\_\_\_

Answer 38

Exstrophy of the bladder / cloaca involves failure of mesoderm migration into the cloacal membrane / ventral abdominal wall ad breakdown of the ectoderm / anterior bladder / cloacal wall, exposing posterior mucosa

Question 39

8-weeks is called the ____ stage of sexual development because both sexes have \_\_\_\_

Answer 39

8-weeks is called the indifferent stage of sexual development because both sexes have identical primordia

Question 40

Gonadal development occurs from the \_\_\_\_

Answer 40

Gonadal development occurs from the gonadal ridge * Epithelial sex cords project into the gonads in two waves

Question 41

In testis development, primary sex cords become \_\_\_\_

Answer 41

In testis development, primary sex cords become seminiferous tubules (sertoli cells)

Question 42

In ovary development, secondary sex cords become \_\_\_\_

Answer 42

In ovary development, secondary sex cords become ovarian follicles (granulosa cells)

Question 43

External genital development involves a ____ and \_\_\_\_

Answer 43

External genital development involves a tubercle and two folds

Question 44

Labioscrotal folds flank ____ and \_\_\_\_

Answer 44

Labioscrotal folds flank UG folds and genital tubercle

Question 45

Lower UG sinus becomes the ____ in the female and UG folds the \_\_\_\_

Answer 45

Lower UG sinus becomes the vestibule in the female and UG folds the labia minora

Question 46

UG sinus in the male forms most of the \_\_\_\_

Answer 46

UG sinus in the male forms most of the penile urethra

Question 47

Clitoris is homologous to the \_\_\_\_

Answer 47

Clitoris is homologous to the penis

Question 48

Labia majora are equivalent to the \_\_\_\_

Answer 48

Labia majora are equivalent to the scrotum

Question 49

While most of the penile urethra comes from a ventral fusion of the urogenital sinus, the ____ in the glans comes from an \_\_\_\_

Answer 49

While most of the penile urethra comes from a ventral fusion of the urogenital sinus, the navicular fossa in the glans comes from an ectodermal invagination from the end of the penis

Question 50

Two primordia of the male urethra must \_\_\_\_

Answer 50

Two primordia of the male urethra must fuse

Question 51

Failure of the urogenital folds to fuse leads to \_\_\_\_

Answer 51

Failure of the urogenital folds to fuse leads to hypospadius

Question 52

Summarize female primordia

Answer 52

Female primordia

Question 53

Failure of the paramesonephric ducts to fuse with each other or the urogenital sinus leads to \_\_\_\_

Answer 53

Failure of the paramesonephric ducts to fuse with each other or the urogenital sinus leads to agenesis

Question 54

Summarize male primordia

Answer 54

Question 55

Mesonephric is \_\_\_\_, while paramesonephric is \_\_\_\_

Answer 55

Mesonephric is male, while paramesonephric is paramesonephric * Complicating factors: three successive kidneys, mesonephros is huge, mesonephros changes its function from urinary to genital in the male (or at least its duct system)

Question 56

Summarize urogenital development

Answer 56

Urogenital development summary * Early UG development: intermediate mesoderm * Nephrogenic ridge, genital ridge, cloaca (rectum, UG sinus - bladder, urethra, vestibule) * Kidneys: pronephros, mesonephros, metanephros * Internal genital organs: gonads, mesonephric ducts, paramesonephric ducts * Gonads (from genital ridge): primary and secondary sex cords * External genital organs: genital tubercle, urogenital folds and sinus, labioscrotal folds