Intersex Flashcards
1
Q
What are types of sex?
A
Genetic sex:
XX=female
XY=male
Phenotypic sex:
-appearance
Gonadal sex:
- testes=male
- ovaries=female
Behavioural/psychological:
- how the person self-identifies (gender identity), if the “assigned sex” is different than the gender identity they are transexual
- transexual is a medical/historical term that is more binary, transgender is less binary
- the term “trans” is non-medical
2
Q
Describe the embryo at 5 weeks
A
- mesonephric kidney which has mesonephric duct (Wolfiann duct)
- paramesonephric duct
- indifferent gonad (potential ovary on outer surface, potential testis in stroma)
- ducts drain into the cloaca (will divide and become rectum in back and bladder up front) the urogenital sinus
3
Q
What does the Y chromosome do at 6 weeks?
A
- presence of active Y chromosome leads to differentiation of the genital tract after about 6 weeks
- the uro part of the urogenital development happens concurrently
4
Q
How does the Y chromosome create male characteristics
A
- sex determining region of Y (SRY gene) gives testis determining factor (TDF)
- TDF is essential for generating XY phenotype by stimulating Sertoli cells in gonad which make anti-Mullerian hormone (AMH) causing the Mullerian ducts to regress
- paramesonephric (Mullerian) ducts typically form female genital tract
- TDF affects Leydig cells in gonad which make testosterone and androgens which stimulates mesonephric ducts to develop in male
- mesonephric ducts give a lot of male repro tract
- testosterone stimulates secondary male characteristics
5
Q
Describe the XX embryology
A
- outer part of indifferent gonad develops into ovary
- paramesonephros occurs and end up with more female phenotype
- paramesonephric ducts give fallopian tubes which fuse with uterus/cervix/vagina
- no anti-Wolffian system/hormone
6
Q
Describe renal and gonadal development in XY phenotype
A
- lose paramesonephric duct and mesonephric kidney
- convert indifferent gonad to testes which descends and occurs at same time as the development of metanephric kidney
- kidney ascends to position on posterior body wall
- gonad descends with the mesonephric duct which makes the vas deferens
- pass each other and ureter is underneath vas deferens (water under the bridge)
7
Q
What is persistent Mullerian duct syndrome?
A
- if the paramesonephric ducts do not degenerate (usually because of a shortage of MIS) then the testicles can be held up in the abdomen or pelvis
- bilateral cryptorchidism
8
Q
Describe the descent of the testes
A
- the descent of the testes into the scrotum must occur through the inguinal canal
- the inguinal canal has a deep ring (opens to the abdomen) and a superficial ring which opens to the scrotum
- the testes will move downwards with gubernaculum
- as testicle gets pulled down it pulls some peritoneum
- happens late in 3rd trimester
- peritoneum must seal off so that bowel material does not enter scrotum
9
Q
A
10
Q
A
11
Q
What is the obliterated processus vaginalis? Scrotal cavity?
A
- results from the inguinal canal
- scrotal cavity is a potential space
- visceral and parietal layer of tunica vaginalis which is lost peritoneum
- epididymis which contains the seminiferous tubules
12
Q
What is the path of the sperm?
A
- testis
- epididymis
- vas deferens
13
Q
What is a hematocoele/hydrocoele?
A
-fluid or blood filling scrotal cavity
14
Q
When is orchidopexy required?
A
- if testes do not descend
- about 4% of male newborns have undescended testis
- this is much higher in premature babies since the inguinal part of the testicular descent is a 3rd trimester occurrence
- usually there will be a period of watchful waiting to see if testis descend by itself
- about 75% will descend in the first year
15
Q
A
- abdominal incision
- take the testicle out through abdominal incision (cut away gubernaculum)
- testicle has blood supply and nerve coming with it
- attach suture material to the end of the testis and put the suture material down through the scrotum
- pull on the suture material to pull the testicle into place in the scrotum
- seal off the bottom of the inguinal canal
16
Q
Why do the male gonads end up outside of the body?
A
- sperm
- spermatozoa will only develop at temperatures 2-3 degrees below body temperature
- to maintain this temperature the testes will move up and down in an attempt to keep at the proper temperature
- movement upwards is accomplished with the cremaster muscle (striated, extension of interal oblique muscle which comes down as part of wall of inguinal canal)
- dartos muscle compresses the scrotum (smooth muscle, reflexes control it)
- to cool down, relax cremaster and dartos and testicles move away from body
- both are activated to keep testes close to abdomen
17
Q
Describe the testicular thermostat
A
- gonadal artery is surrounded by a venous plexus
- warm arterial blood
- venous blood in panpiniform plexus has been in testicle and is returning to body
- the blood in panpiniform plexus has cooled from being outside of body and so it will cool the incoming warm blood
- allows us to have cooler blood to testicle to allow for 2-3 degree difference
18
Q
What is an inguinal hernia?
A
- males have almost all of the inguinal hernias (about 25 to 1) and there are close to 100 000 hernia repairs a year in Canada
- inguinal canal had to stay open for gonad to descend which makes a weak point in abdominal wall
- this can allow a part of intestine to push out and through the fascia of the abdomen
- comes into the scrotum
- this is a direct hernia because the hernia came directly through the abdominal wall into the inguinal canal
- normally acquired later in life
20
Q
How does external genitalia develop (at 5 week stage)?
A
- start with the indifferent stage
- genital tubercle with labioscrotal swellings on either side
- urethral folds in middle
- genital tubercle becomes clitoris or penis
- labioscrotal swelling becomes labia majora or scrotum
- urethral folds become labia minora and form part of urethra
- urogenital sinus is open to the bladder
21
Q
How does external genitalia develop (at 10 weeks)?
A
- under the influence of androgens (regardless of XX or XY) the urethral folds begin to meet and seal up
- in females without androgen influence, the urethral folds will not seal up
- labioscrotal swellings will swell towards each other
- tip of genital tubercle begins to take on appearance of glans penis
22
Q
How does external genitalia develop (after 10 weeks)?
A
- scrotum forms and is divided by midline raphe (where labioscrotal swellings have fused)
- urethra has sealed and now opens at the tip of the penis in the glans and are emptying now at the tip of the glans penis
23
Q
How does the female external genitalia develop?
A
- labioscrotal swellings don’t fuse and make the labia majora
- the urogenital folds don’t fuse and stay as labia minora
- urethra opens in the area that the two urogenital folds did not fuse
- genital tubercle becomes clitoris
- with no androgens around, tend to get this pattern
25
Q
Describe XX Intersex
A
- chromosomally female
- external genitalia appear to be male
- typically results from virilization of female fetus by male hormones
- may be confused as to whether it is undescended testis and a micropenis
- chromosomal test will reveal that it is clitoromegaly and a fused labia majora
- male hormones result from overactive adrenal gland in fetal development
- disease of the adrenal is called congenital adrenal hyperplasia (CAH)
- common cause of XX intersex
26
Q
Describe XY intersex
A
- micropenis with cryptorchid, and hypospadias (urethra opens at base of penis because urethral folds didn’t fuse)
- has many causes but generally they are the results of inadequate supply or insensitivity to male hormones
- most common cause is androgen insensitivity syndrome (AIS) where there are poorly formed or an absence of receptors
- a shortage of androgens would give same result
- typically no female internal organs because they would have made anti-mullerian hormone except for a short blind-ended vagina
- typically will present in adolescence with no menstrual cycle/infertile and that is because they have no female internal organs
