Male vs. Female Differentiation

Question 1

How would females develop?

Answer 1

Typically this is the default in the absence of SRY from the Y chromosome. In the absence of SRY, AMH is not produced by male sertoli cells and the mullerian structures do not regress. When this happens mesonephric ducts regress and paramesonephric ducts develop into the female genital tract (fallopian tubes, uterus, and upper vagina (not the ovaries!)). The lower vagina forms from an invagination of the perineal body

NOTE: Mayer-Rokitansky-Kuster Hauser Syndrome is mullerian agenesis and may present as primary amenorrhea (due to a lack of uterine development) in females with fully developed 2ndary sexual characteristics (functional ovaries)

Question 2

What do the Mesonephric (wollfian) ducts form in males in the presence of SRY, AMH (from sertoli cells), and testosterone (from Leydig cells)?

Answer 2

SEED

Seminal vesicles, epididymis, ejaculatory duct, and Ductus (vas) deferens

NOT the prostate

Question 3

Again, what determines male vs female differentiation?

Answer 3

SRY on the Y chromosome that produces testis-determining factor causes the testes to produce sertoli and leydig cells

Question 4

What do sertoli cells produce that cause regression of the paramesoneprhic ducts (mullerian)?

Answer 4

AMH

Question 5

What do Leydig cells produce that promote the proliferation of the wolffian ducts into the INTERNAL male genitalia (except the prostate)?

Answer 5

testosterone

Question 6

What stimulates formation of the external male genitalia and the prostate?

Answer 6

DHT

Question 7

How is DHT made from testosterone in the periphery?

Answer 7

5a-reductase (inhibitors include finasteride and dutasteride)

NOTE: 5a-reductase deficiency causes ambiguous external genitalia until puberty

Question 8

What would happen if you had SRY present, but no sertoli cells?

Answer 8

The lack of AMH would cause the formation of BOTH male and female internal genitalia with only male external genitalia and a prostate from DHT (b/c leydig cells would still make testosterone)

Question 9

What are the derivatives of the genital tubercle?

Answer 9

the glans penis and corpus cavernosum/spongiosum in the presence of DHT and the glans clitoris and the vesitcular bulbs in the presence of estrogen

Question 10

What are the derivatives of the urogenital sinus?

Answer 10

Copwer glands and a prostate in the presence of DHT and

Bartholin glands and urethral/paraurethral glands in the presence of estrogen

Question 11

What are the derivatives of the urogenital folds?

Answer 11

the penile urethra in the presence of DHT and the labia minora in the presence of estrogen

Question 12

What are the derivatives of the labiosacrotal swelling?

Answer 12

the scrotum or the labia majora

Question 13

What is hypospadias?

Answer 13

The abnormal opening of the urethral meatus in the inferior (ventral) side of the penis due to failure of urethral folds to close

Hypo= below

Question 14

What are consequences of hypospadias?

Answer 14

UTIs

Question 15

What is epispadias?

Answer 15

Abnormal opening of the penile urethra on the superior (dorsal) side of the penis due to faulty positioning of the genital tubercle)

If you have Epispadias, you might hit your Eye when you pEE

Question 16

What is a potential consequence of epispadias?

Answer 16

extrophy of the bladder

Question 17

What structures aid in the descent of the testes?

Answer 17

The gubernaculum (band of fibrous tissue), which anchors the tests within the scrotum in men

processus vaginalis (evagination of peritoneum) which forms the tunica vaginalis in men and is obliterated in women

Question 18

What are the remnants of the gubernaculum in women?

Answer 18

ovarian ligament and round ligament of uterus

Question 19

What is the venous drainage of the gonads?

Answer 19

left ovary/testis goes to the left gonadal vein, to the left renal vein, and then to the IVC while the

right ovary/testis drains to the right gonadal vein, and then directly to the IVC

Question 20

Why is varicocele more common in the left side?

Answer 20

Because the left gonadal vein enters the left renal vein so sharply

Question 21

What is the lymph drainage of the ovaries/testes?

Answer 21

para-aortic lymph nodes

Question 22

What is the lymph drainage of the distal 1/3 of the vagina/vulva/scrotum?

Answer 22

superficial inguinal nodes

Question 23

What is the lymph drainage of the proximal 2/3 of the vagina and uterus?

Answer 23

obturtor, external iliac, and hypogastric nodes

Question 24

What is the role of the suspensory ligament of the ovaries?

Answer 24

connects the ovaries to the lateral pelvic wall

Question 25

What is contained with the suspensory ligament of the ovaries?

Answer 25

ovarian vessels

Question 26

What is the role of the cardinal ligament?

Answer 26

connect the cervix to the side wall of the pelvis

Question 27

Whats contained with the cardinal ligament?

Answer 27

uterine vessels (ureter at risk of injury during ligation of uterine vessels in a hysterectomy) water under the bridge

Question 28

What ligament connects the uterine fundus to the labia majora?

Answer 28

the round ligament of the uterus (remember this is derived from the gubernaculum)

Question 29

What structures does the round ligament contain?

Answer 29

Artery of Sampson

Question 30

What are the components of the broad ligament?

Answer 30

mesosaplinx, mesometrium, and mesovarium

Question 31

What does the ligament of the ovary do?

Answer 31

connects the lower pole of the ovary to the lateral uterus (no structures run in this ligament) remember this is also a deriv of the gubernaculum

Question 32

Describe the epithelium of the female genital tract?

Answer 32

Simple cuboidal in the ovaries, simple columnar in the fallopian tubes to the endocervix Stratified squamous in the exocervix to the vagina

Question 33

What are the parts of the male reproductive tract?

Answer 33

Sperm is made in the seminiferous tubules, to the rete testes, and then sent to the epididymis, then to the ejaculatory duct where the seminal vesicles join and secrete fructose and prostaglandins, and then through the urethra and out the penis