The development and sexual differentiation of the reproductive system

Question 1

what are the 4 parts of sexual development? [4]

Answer 1

1. Genetic sex
‐ Chromosomal composition: XX or XY

‐ Determined at fertilization, yet this doesn’t mean the organs have developed as male or female at this stage

2. G_onadal development_
   ‐ Development of testes or ovaries

‐ Defined during embryonic development

3. Development of the sex‐specific internal ducts and external genitalia

‐ Hormone dependent
‐ Defined during fetal development

4.Secondary sex characteristics

‐ Defined at puberty

Question 2

which of the following is determined in fetal development

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Answer 2

which of the following is determined in fetal development

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Question 3

which of the following is determined at fertilisation

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Answer 3

which of the following is determined at fertilisation

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Question 4

which of the following is determined during embryonic development

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Answer 4

which of the following is determined during embryonic development

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Question 5

which of the following is determined during puberty

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Answer 5

which of the following is determined during puberty

genetic sex
gondal development
development of sex-specific internal ducts and external genitalia
secondary sex characteristics

Question 6

where do gonads appear at the start of their development? [1]
what does these ^ eventually become in the gonads? [1]

Answer 6

where do gonads appear at the start of their development? [1]
gonads appear as longitudinal gential ridges

what does these ^ eventually become in the gonads? [1]
eventually become ducts / tubules in the gonads

Question 7

what is A & B?

Answer 7

A = genital ridges
B = hindgut

Question 8

explain the process primordial germ cell migration in the developing gonad xx

when and where does it occur? [2]

Answer 8

explain the process primordial germ cell migration in the developing gonad xx

i) when and where does it occur? [2]
* *primordial germ cell migration: moves to genital ridge at 4 weeks**

Question 9

after primordial germ cells have migrated ot the genital ridges, which 3 cell types are found in the ridge? [3]

what are each of their functions? ^

Answer 9

1. primordial germ cell (just migrated) –> future gametes (spermatogonia and oogonia).

2. mesothelial cells –> seminiferous tubules and ovarian tubules (waiting to be activated)

3. mesenchymal cells –> leydig cells in males, stromal cells in female

Question 10

what are the different types of mesenchymal cells in male and female? [2]

Answer 10

male = **leydig cells**
female = **stromal cells**

Question 11

what are the name of the genital / internal ducts in

males: [1]
females [1]

Answer 11

what are the name of the genital / internal ducts in

males: wolffian ducts
​females: mullerian ducts

Question 12

what do mullerian ducts give rise to ? [3]
what do wolffian ducts give rise to ? [3]

Answer 12

what do mullerian ducts give rise to ? [3]
uterus, fallopian tubes, cervix & upper 1/3 vagina

​what do wolffian ducts give rise to ? [3]
vas deferens, seminal vesicles and epididymis

Question 13

how does the body determine if you produce mullerian ducts or wolffian ducts? [2]

which hormones are secreted / what happens after this has happened to continue development of wolffian ducts? [2]

Answer 13

no hormonal input: develop mullerian ducts

hormanol input: wolffian ducts

then:

• SRY on Y chr encodes for testes-determining factor –> induces Leydig cells to produce testosterone
• *sertoli cells** in testes produce mullerian inhibitory factor: inhibits the formation of mullerian duct

Question 14

Answer 14

Question 15

what does DHT cause the production of? [3]

Answer 15

DHT, which will give rise to the male external genitalia (prostate, penis and scrotum).

Question 16

what happens if have patients who’s leydig cells dont secrete testosterone?

Answer 16

Sometimes testosterone may not be secreted by Leydig cells.

• Patient presents as female with female external genitalia
• Primary amenorrhea
• No genital ducts/associated structures
• Undescended testes as genetically male XY
• Sertoli cells will still produce MHF which inhibits Mullerian duct, so you will have no uterus , fallopian tubes, cervix or upper vagina

Question 17

when does differention into male / female occur?

week 6
week 7
week 8
week 9
week 10

Answer 17

when does differention into male / female occur?

week 6
week 7
week 8
week 9
​week 10

have both the mullerian duct and wollfian duct up to 7 weeks - then differentation occurs

Question 18

male development:

Wolffian duct persists to give rise to what? [3]

what happens to the Mullerian ducts? [1]

Answer 18

Wolffian duct persists to give rise to epididymis seminal vesicles and vas deferens

Mullerian duct will begin to degenerate.

Question 19

female development:

what happens to mullerian ducts? [1] what do they turn into? [1]

Answer 19

what happens to mullerian ducts? [1]
close in and fuse into a continuum

what do they turn into? [1]
vaginal/ uteral canal

Question 20

what can happen to mullerian duct to create anomolies?

Answer 20

double uterus
double vagina,
double uterus presenting to single vagina
sometimes only one duct persists, etc.

Question 21

A double uterus or a bicornuate / unicornuate uterus results from? [2]

Answer 21

• Incomplete fusion of Mullerian ducts inferiorly
• Incomplete development of ducts

Question 22

which hormone controls the formation of external genitalia?

testosterone
MIF
DHT
cHG
LH

Answer 22

which hormone controls the formation of external genitalia?

testosterone
MIF
DHT !!!
cHG
​LH

Question 23

formation of the external genitalia:

what does the labioscrotal swelling turn in (in male / female?) [2]
what does the urogenital folds turn into (male / female) [2]
what does the genital tubercle turn into? (male / female) [2]

Answer 23

what does the labioscrotal swelling turn in (in male / female?) [2]
labia majora (f)
scrotum

what does the urogenital folds turn into (male / female) [2]
ventral penis / penile urethra
labia minora

what does the genital tubercle turn into? (male / female) [2]
glans penis
glans clitoris

Question 24

what is the position of the testes as they descend?

2nd month [1]

3rd month [1]

7th month? [1]

9 month? [1]

Answer 24

what is the position of the testes as they descend?

2nd month [1]
abdomen wall

3rd month [1]
migrate through abdomen - gubernaculum starts to develop and guide the testes down into the future scrotum

7th month? [1]
scrotum

9 month? [1]
9 months there should be a small area of gubernaculum​

Question 25

label A & B [2]

Answer 25

A: **gubernaculum testis** B: **vaginal process**

Question 26

during descent of testis: what happens to transverse abdominis? [1] what happens to processus vaginalis [2]

Answer 26

during descent of testis: what happens to transverse abdominis? [1] **doesnt get carried through to testis** what happens to processus vaginalis [2] * *should regress - if not turn is indirect inguinal hernias !** * *turns into tunica vaginalis**

Question 27

label A-D

Answer 27

A: **transversalis fascia** B: **transversus abdominis** C: **internal oblique** D: **External oblique**

Question 28

what is the name for when one or both of the testicles do not descend into the scrotum while the fetus is developing? [1] what is an ectopic testes? [1]

Answer 28

Cryptorchidism **ectopic testis:** where one of the testicles has not descended into the scrotum as normal, but instead has taken a different path and has descended **through the abdominal cavity** until it has settled in the **pre-pubic area in the inguinal canal**, instead of in the scrotum.

Question 29

indirect / congenital hernia occurs because of a protrusion of an abdominal viscus into WHICH STRUCTURE? [1]

Answer 29

An indirect inguinal hernia is a congenital hernia, regardless of the patient's age. It occurs because of protrusion of an abdominal viscus into an open processus vaginalis

Question 30

describe relocation of the ovaries (move from where --\> where?)

Answer 30

Move from **superior lumbar region** and relocate to the **lateral wall of the pelvis**

Question 31

label A-E

Answer 31

A: Bladder B: Vas deferens C: seminal vesicles D: prostate E: ureters

Question 32

which structures transverse the prostate? [2]

Answer 32

urethrea ejaculatory duct

Question 33

which part of the urethrea do the common ejaculatory ducts open into? membranous urethra spongy urethra prostatic urethra preprostatic urethra

Answer 33

which part of the urethrea do the common ejaculatory ducts open into? ​membranous urethra spongy urethra **prostatic urethra** preprostatic urethra

Question 34

where is prostate in relation to bladder? superior inferior lateral medial

Answer 34

where is prostate in relation to bladder? superior **​inferior** lateral medial

Question 35

how many lobes does the prostate have? [3]

Answer 35

1 median 2 lateral

Question 36

where does the suspenosry ligament run from (where to where)? [2]

Answer 36

_where does the suspenosry ligament run from (where to where)? [2]_ **wall of the cavity --\> uterus**

Question 37

label the different parts of the fallopian tube

Answer 37

Question 38

which is the most common site of fertilisation in fallopian tube? infundibulum ampulla isthmus ​fimbrae

Answer 38

which is the most common site of fertilisation in fallopian tube? infundibulum **ampulla** isthmus ​fimbrae

Question 39

what are the lumen called that surround the cervix? [1]

Answer 39

The lumen surrounding cervix divided into **fornices** – ant, post, and 2 lateral

Question 40

name this structure [1]

Answer 40

ureters