The development and sexual differentiation of the reproductive system Flashcards
what are the 4 parts to sexual development
- Genetic sex
- Gonadal development
- Development of the sex specific internal ducts and extemal genitalia
- Secondary sexual characteristics
describe the 4 parts to sexual development
- Genetic sex
- Chromosomal composition (determined at fertilization)
- XX or XY - Gonadal development
- Development of testes or ovaries (defined during embryonic development)- even though you have a Y chromosome things don’t always develop the way that they should - Development of the sex-specific internal ducts and external genitalia
- Hormone dependent (defined during fetal development) - Secondary sexual characteristics
- Defined at puberty
when do male or female characteristics start to show
- No male or female characteristics until week 6-7
what is close to the posterior wall
Close to the posterior wall there is the gonadal ridge where testes or ovaries form, they are close to where the kidneys are forming
where do the primordial germ cells come from
Primordial germ cells which come from the yolk sac and them migrate in up through the GI system and through the perionteum and into the gonadal ridges
what is the cloaca
- this is unseparated bladder and the bottom end of the GI system,
- this is where the GI system exits and where the bladder will be formed from,
what produces urine during foetal development
The mesonephros is the embryonic kidney this is producing urine during foetal development and is producing amniotic fluid
what are the ducts that are present in male and female foetus
- male duct - wollfain duct
- women - mullerian duct
- women get rid of the wolfing duct
what does the wolffian duct become
vas deferens, epididymis and seminal vesicles
what does the mullerian duct become
the uterus, fallopian tubes, cervis and upper 1/3 of vagina
what are the three types of cells in the ridge
- Primordial germ cells
- Mesothelial cells
- Mesenchymal cells
what do the 3 types of cells in the ridge form
- Primordial germ cells – PGCs start to migrate to gential ridges in week 4 they form the future gametes
- Mesothelial cells – these form the seminiferous tubules and ovarian follciles
- Mesenchymal cells – these form supporting cells and connective tissue
what determines male sex
SRY gene
how does the SRY gene determine male sex
- Determines that you produce Leydig and Sertoli cells
- From Leydig cells you produce testosterone and DHT
- From Sertoli cells you produce MIF which si Mullerian inhibitory factor – it inhibits the mullerain duct it causes the Mullerian duct to shrink and disappear because we don’t need it but you keep the Wolffian
- The DHT helps with the development of the prostate penis and scrotum
what is 46 XY DSD
- Testosterone not formed so prostate does not form properly
- Patient presents as female with female external genitalia
- Primary amenorrhea
- No genital ducts/associated structures
- Undescended testes as genetically male XY
- Might stil have the antimalllurian factor so you end up with no uterus, fallopian tubes cervix and upper 1/3 vagina
what does the mullarian duct in females do
- it fuses in the midline to form the uterus
what is important in the descending of the ovaries and testes
- the gubernaculum
what separates the mullarian duct from the upper surface of the vagina
heimen
what uterus defects can you end up with
- Where it doesn’t fuse or with a double vagina
- Can end up with a single vagina with two uteruses
- Can end up with just one uterus because the other one doesn’t fuse properly
how can a double uterus or a unicorunulate uterus result
– Incomplete fusion of Mullerian ducts inferiorly
– Incomplete development of ducts
– Failure of one of the ducts
what parts of genital do foetus have at
- 8 weeks
- 9 weeks
- 12 weeks
– Genital tubercle – Urogenital fold – Labioscrotal fold / swelling • 9 weeks sexual differentiation • Distinctly male / female by end of week 12
how do the male gonads change position during development
- 4cm long
- 2mm above the inguinal ligament
- Starts at deep inguinal ring
- Emerges at superficial inguinal ring
- and then pulled into the testes
how are the testes pulled from the inguinal canal
- they are attached to the gubernaculum - this contracts
- pulls the testes through the inguinal canal
- it also brings the parietal peritoneum with it, it moves the testes into the scrotum
what forms the tunic vaginalis
- perionteal seals of and forms the tunica vaginalis
what does the tunica vaginalis do
– protects them and gives them cushioning
- It brings with it external spermatic fascia, cremaster muscle, transverses abdomins, transversalis fascia, internal oblique, external oblique and internal spermatic fascia
what are two abnormalities of testicular descent
- cryptorchidism
- ectopic testes
- congenital indirect inguinal hernia
what is cryptorchidism
– Uni or bi-lateral
– If testes remain within abdomen – sterility
– Normally in inguinal canal and often descend spontaneously
– Deficiency of androgen production could be a reason for it
what could be a reason for cryptorchidism
– Deficiency of androgen production could be a reason for it
what causes an ectopic testes
- interstitial ectopic occurs most frequently
– Occurs when the gubernaculum passes to an abnormal location this happens when it is not attached properly and it it can end up in the anterior thigh
what causes a congenital inguinal hernia
- If the communication between the tunica vaginalis and the peritoneal cavity fails to close, a persistent processus vaginalis exists. A loop of intestine may herniate through
- Herniation passes through the deep inguinal ring and passes through the inguinal canal
describe the vas deferns
• End of ductus deferens expanded in ampulla
• Ductus deferens joins duct of seminal vesicle to form
– Common ejaculatory duct
where do the vas deferent travel
• Within spermatic cord, ductus deferens passes through inguinal canal, then inferiorly/medially
where does the ejaculatory duct go
• Ejaculatory duct penetrates through prostate to connect with urethra at seminal colliculus
describe the structure of the seminal vesicles
- Coiled, sacculated between bladder and rectum
* Separated from rectum behind by rectovesical fascia, and rectovesical pouch
why is the male not sterile for another 3-6 months after a vasectomy
• - patient not sterile for 3-6 months because of sperm in the vesicles stops ability of the sperm to get form the testes to back round
describe the common ejaculatory ducts
– 2cm long
– Traverses the prostate to open in the prostatic urethra
describe the structure of the prostate
– Lies below bladder on pelvic floor
– 1 Median and 2 lateral lobes
– Traversed by urethra and ejaculatory duct
what is prostatic hypertrophy
– Enlarges esp. median lode – disturbs vesicular sphincter action and rendering micturition difficult. Transurethral resection of the Prostate (TURP) permits the coring out of the median lobe
where is cancer in the prostate gland
– Cancer of the prostate commonly affects the lateral lobes and may be felt as a hard irregular mass on rectal examination
where do the ovaries relocate
- superior lumbar region to the lateral wall of the pelvis
-
what does the processes vaginalis of the peritoneum do
- Processus vaginalis of the peritoneum traverses the transversalis fascia at the site of the deep inguinal ring
- forming the inguinal canal (as in the male) and protrudes into the developing labium majus
what does the female gubernaculum come postnatally
- Becomes the Ovarian ligament
* And the Round ligament of uterus
where does the round ligament pass
• Round ligament passes through the inguinal canal and attaches to labium majus
what does the ovarian ligament originate from and what does it do
• Ovarian ligament (cranial gubernaculum)
– Ovary to uterus
what does the round ligament of the uterus originate from and go
• Round ligament of uterus (caudal gubernaculum)
– Uterus down via the inguinal canal to the labium majorum via inguinal canal
what does the peritoneum do
- Lies like a sheet over the pelvic viscera
what does the pouchh of dogluas do
accumulation of blood or pus
what are the two peritoneal pouch
- Vesciounterine pouch
- Pouch of douglas
what does the suspensory ligament of the ovary have in it
- The suspensory ligametns of the ovary also bring the gonadal artery and vein into the ovary
what supports the uterus
• Levator ani muscles and the perineal body
• Sacrocervical ligaments
– Fibro musc bands cervix to sacrum
• Transverse cervical (cardinal) ligaments
– Fibromusc from lat. Pelvic walls to cervix and upper vagina
• Pubocervical Ligaments
– 2 firm bands CT from pubis to cervix (either side of bladder)
describe the structure of the vagina
• Thin muscular tube extending backwards from the vulva to the uterus
• Upper half above pelvic floor, lower perineum
• Upper end of vagina pierced by cervix
– The lumen surrounding cervix divided into fornices
• Anterior,
• Posterior
• 2 lateral
what is the lumen surrounding the cervix divided into
– The lumen surrounding cervix divided into fornices
• Anterior,
• Posterior
• 2 lateral
where are the things that support the vagina
- Ant – bladder/urethra
- Post – pouch of douglas, ampulla of rectum, perineal body
- Lat – ureters,levator ani, urogenital diaphragm and bulb of vestibule
- Upper –the transverse cervical, pubocervical and sacrocervical ligaments
- Middle- the levator ani and the urogenital diaphragm
- Lower – perineal body
where do gondal blood supply orignate form
• Gonadal vessels originate from abdominal aorta or renal vessels
what are the two arteries that make up the gonadal arteries
- testiuclar
- ovarian
describe where the testicualr artery goes
retroperitoneally around pelvic rim to deep inguinal ring
describe where the ovarian artery is
found in suspensory ligament of ovary
what are the relations of the bladder
– Inferolaterally – fat filled retropubic space, levator ani muscle and obturator internus
– female ♀ superior and posterior surface– uterus, inferiorly – urogenital diaphragm.
– male - ♂ superior surface – rectum, posteriorly - seminal vesicles and ducta deferentia, inferiorly - prostate
describe where the ureters travel
- Pass over the pelvic brim at bifurcation of common iliac arteries in front of the sacroiliac joint
- Run on lateral walls of pelvis
- Opposite ischial spine, curve anteromedially
- Oblique entrance into bladder – one way flap valve
