pelvic embryology

Question 1

What is the name given to the gonads when they first start development

Answer 1

genital ridges

Question 2

what cell layer are the genital ridges (gonad) delivered from ?

a - intramediate mesoderm
b - lateral mesoderm
c - paraxial mesoderm
d- endoderm

Answer 2

Intermediate mesoderm

Question 3

where do the germ cells move from to reach the genital ridges

Answer 3

germ cells move from the endoderm of the yolk sac to the genital ridges - this process starts at week 4 and finishes by week 6

Question 4

What week in embryological development do the germ cells begin to migrate to the genital ridges?

week 2
week 3
week 4
week 5

Answer 4

week 4 the process starts

Question 5

at what week in embryological development can we say that migration of germ cells to the genital ridges has completed

A WEEK 4
B WEEK 5
C WEEK 6
D WEEK 7

Answer 5

week 6

Question 6

what is the karyotype of the male gonad

Answer 6

XY

Question 7

what is the karyotype of the female gonad

Answer 7

XX

Question 8

what gene contained in the male Y chromosome is responsible for the development of the male gonad?

Answer 8

SRY gene

Question 9

Under the influence of the SRY gene the sex cords differentiate into what structure?

Answer 9

Testis cords

Question 10

where is sperm produced in the male sex cords

Answer 10

seminiferous tubules

Question 11

Leydig cells develop from what embryological cell layer

Answer 11

Intermediate mesoderm

Question 12

what hormone do Leydig cells produce

Answer 12

Testosterone

Question 13

during which week do leydig cells start to produce testosterone

A WEEK 4
B WEEK 6
C WEEK 8
D WEEK 10

Answer 13

WEEK 8 - production of testosterone drives the differentiation of the internal and external genitalia

Question 14

what type of cords develop in the ovaries due to the absence of the SRY gene on the Y chromosome?

Answer 14

cortical cords

Question 15

What are the two types of ducts that all embryos contain in the first weeks of urogenital development in the indifferent stage.

Answer 15

Mesonephros (wollfian) duct
Paramesonephros (mullerian) duct

Question 16

which ducts remain in men (XY)

Answer 16

mesonephros (wolffian) ducts remain whilst the paramesonephros (mullerian) ducts regress

Question 17

which ducts remain in females (XX)

Answer 17

Paramesonephros (mullerian) ducts remain and the mesonephros (wolffian) ducts regress

Question 18

what hormone do leydig cells produce

Answer 18

testosterone

Question 19

what hormone do sertoli cells produce

Answer 19

AMH (anti-mullerian hormone)

Question 20

under the presence of testosterone what do the mesonephric ducts develop into?

Answer 20

testosterone cause mesonephric ducts to differentiate and develop into efferent ductules, epididymis, vas deferent and the seminal vesicles

Question 21

Sertoli cells secrete AMH. What is the purpose of this in male gonads?

Answer 21

AMH causes regression of the paramesonephric (mullerian) ducts

Question 22

in men what is the name of the embryological remnant of the paramesonephric duct

Answer 22

Appendix testis

Question 23

in females what is the name of embryological remnant of the mesonephros (wolffian duct)

Answer 23

Vestigial remnant - Gartner’s duct

Question 24

in females the absence of AMH allows for the development of what ducts

Answer 24

Paramesonephric ducts

Question 25

What are the three parts of the paramesonephric duct in females and what do they form

Answer 25

cranial --> fallopian tubes horizontal --> fallopian tubes caudal --> uterus, cervix and upper 1/3 of the vagina

Question 26

Fusion of the caudal paramesonephric ducts leads to formation of what structures in females

Answer 26

uterus, cervix and upper 1/3 of the vagina

Question 27

Failure of the paramesonephric ducts to fuse in female embryological development can lead to what anatomical variant

Answer 27

bicorne uterus

Question 28

the lower 1/3 of the vagina is formed from what structure

Answer 28

sinovaginal bulbs

Question 29

H

Answer 29

H

Question 30

what type of cells migrate from the primitive streak to the cloacal membrane to form a pair of cloacal folds?

Answer 30

mesenchymal cells

Question 31

fusion cranially of the cloacal folds forms what structure

Answer 31

genital tubercule

Question 32

fusion caudally of the cloacal folds form what two structures

Answer 32

anteriorly -urethral folds posteriorly - anal folds

Question 33

what androgen drives differentiation of the male external genitalia

Answer 33

DHT (dihydrotestosterone)

Question 34

in men the genital tubercle becomes what structure?

Answer 34

phallus (penis)

Question 35

the urethral folds in men develop to become what structure

Answer 35

urethral groove, this closes by the fourth month forming the penile urethra

Question 36

what do the genital swellings in men become

Answer 36

scrotal swellings

Question 37

failure of the urethral folds to completely close can cause what genital abnormality

Answer 37

hypospadias

Question 38

what hormone drives female external genitalia to develop

Answer 38

oestrogen

Question 39

what is the embryological origin of the clitoris

Answer 39

genital tubercle

Question 40

what is the embryological origin of the labia minora

Answer 40

urethral folds

Question 41

what is the embryological origin of the labia major

Answer 41

genital swellings

Question 42

what structure attaches the gonads to the scrotum or labia in embryological development?

Answer 42

gubernaculum (a ligamentous structure derived from mesenchyme)

Question 43

the scrotal ligament in men is the embryological remnant of what strucutre

Answer 43

the gubernaculum

Question 44

what does the gubernaculum become in females following embryological development

Answer 44

ovarian ligament and round ligament of the uterus

Question 45

what is the purpose of 5 alpha reductase

Answer 45

converts testosterone into DHT

Question 46

by what week are gonadal ridges formed

Answer 46

week 6

Question 47

By what week in embryological development are ovaries visible

Answer 47

week 9

Question 48

until what week do mullerian and wolffian ducts remain undifferentiated

Answer 48

week 8

Question 49

until what week does the urogenital sinus remain undifferentiated until

Answer 49

week 9

Question 50

what week in development is external genitalia development completed

Answer 50

week 12

Question 51

what embryological cell layer does the urogenital system develop from? A- paraxial mesoderm B- intermediate mesoderm C- lateral mesoderm D- inferior mesoderm

Answer 51

B - intermediate mesoderm

Question 52

a patient is diagnosed with a gartner's cyst. What is the cause of this pathology A) failure of paramesonephric duct to degenerate B) failure of the mesonephic duct to generate C) failure of the paramesonephric and mesonephric duct to generate D) failure of the pronephros to degenerate

Answer 52

B - failure of the mesonephric duct (also called wolfian duct) to degenerate fully

Question 53

what hormone can be responsible in males for failure of the urethral folds to fuse and lead to hypospadias A) oestrogen B) testosterone C) LH D) FSH

Answer 53

B - testosterone

Question 54

in females what does the lower 2/3rds of the vagina develop from

Answer 54

sinovaginal bulb

Question 55

what does the upper 1/3rd of the vagina develop from

Answer 55

paramesonephric (mullerian ducts)

Question 56

a patient is diagnosed with vaginal atresia by detection of a transverse septum. What embryological explanation would have caused this clinical finding? A- failure of the sinovaginal bulb to develop and form the vaginal plate B- failure of fusion of the paramesonephric ducts C - failure of cannulisation of the vaginal plate

Answer 56

c

Question 57

what is an absent vagina usual