genital development

Question 1

how does female internal development occur?

Answer 1

this is the default development. mesonephric duct (which connects the temproarily functional mesonephros to the urogenital sinus) will degenerate, while the paramesonephric duct will form (aka mullarian duct). the paramesonephric duct develops into the internal structures like fallopian tubes, uterus, and upper portion of the vagina (the lower vagina is from the urogenital sinus).

Question 2

How would mullerian duct defects manifest in a patient

Answer 2

primary amenorrhea in females with fully developed secondary sexual characteristics, which indicate functional ovaries.

Question 3

How does male internal and external reproductive development occur? include genes, cells, and origin of important structures

Answer 3

SRY gene product is testes determining factor, so primitive gonads deveop into testes with sertoli and leydig cells.
sertoli cells make mullarian inhibitory factor, which causes degeneration of the paramesonephric duct
leydig cells make testosterone. testosterone promotes development of the mesonephric duct, which will eventually form the seminal vesicles, epididymis, ejaculatory duct, and ductus deferens.
5-alpha reductase converts testosterone to DHT, which causes development of the external male genitalia and the prostate

Question 4

bicornate uterus: what happened in development? what are some consequences?

Answer 4

the two paramesonephric ducts (mullerian ducts) has incomplete fusion (if they hadn’t fused at all, the patient would have two entirely separate uteri, 2 cervices, 2 upper vaginal canals). bicornate uterus can lead to recurrent miscarriages.

Question 5

what are two critical problems that can occur during male sexual development? where do they occur?

Answer 5

1. if the sertoli cells do not exist or don’t produce mullerian inhibitory factor, the patient will develop both male and female internal genitalia, but only external male genitalia
2. if the patient is deficient in 5-alpha reductase, (s)he can’t convert testosterone into DHT. the patient will have male internal genitalia and ambiguous external genitalia until puberty, when incr. testosterone levels will cause masculinization

Question 6

What are the male and female homologs derived from the genital tubercle?

Answer 6

male: glans penis and corpus cavernosum and corpus spongiosum
female: glans clitoris and “vestibular bulbs” (internal erectile tissue below the glans clitoris)

Question 7

What are the male and female homologs derived from the urogenital sinus?

Answer 7

male: bulbourethral glands and the prostate gland
female: grater vestibular glands (bartholin glands) and the urethral and paraurethral glands (of skene)

Question 8

What are the male and female homologs derived from the urogenital folds?

Answer 8

male: ventral shaft of the penis
female: labia minora

Question 9

hypospadias vs. epispadias; associations, what happened

Answer 9

hypospadias: the urethra opens onto the inferior side of the penis. this occurs when the urethral folds don’t close properyly
epispadias: the urethra opens onto the superior side of the penis. this happens when the genital tubercle isn’t properly positioned during development.
epispadias is associated with bladder exstrophy (part of the bladder is located outside the body)

Question 10

gubernaculum: function in utero, remnamts

Answer 10

this supports testicular and ovarian descent during development.
in males, it remains to anchor the testes within the scrotum
in females, it becomes the round ligament of the uterus and the ovarian ligament

Question 11

processus vaginals: function in uterno, remnants

Answer 11

in utero, it is an outpouching of the peritoneum that is important for testicular descent. in males, it precedes testes descent down the gubernaculum. it remains as the tunica vaginalis
in females, it disappears.