Urogenital System Part B Flashcards
label
What is genotypic sex?
Sex determined by genotype: 44 autosomes + XY or XX
What is gonadal sex
Genetic sex, as determined by the chromosome constitution, drives the primitive gonad to differentiate into a testis or an ovary.
- transcription factor SRY (sex determining region of chromosome Y) activates the genetic program for testis development. In absence of SRY, ovaries form
__________ (sex determining region of chromosome Y) activates the genetic program for testis development. In its absence, ____ form
transcription factor SRY (sex determining region of chromosome Y) activates the genetic program for testis development. In absence of SRY, ovaries form
What is phenotypic sex?
Gonads produce hormones that direct development of the reproductive tracts and external genitalia
Up to the end of the _____ week, development is the same in males and females and is referred to as the ________ stage
Up to the end of the 6th week, development is the same in males and females and is referred to as the ambisexual/indifferent stage
Gonads form __________ (relative to) mesonephros, from _________ (tissue) that sits on a basolamina
Gonads form medial and parallel relative to mesonephros, from coelomic epithelium: lateral plate mesoderm (splanchnic) and somatic mesoderm (tissue) that sits on a basolamina
Growth of gonadal (genital) ridges:
- Cells of the _______ adjacent to the _______ proliferate
- The cells build-up to create ridges- gonadal or genital ridges
Growth of gonadal (genital) ridges:
- Cells of the coelomic epithelium adjacent to the mesonephros proliferate
- The cells build up to create ridges- gonadal or genital ridges
As the genital/gonadal ridges form, the ________ degenerates and two types of cells invade:
As the genital/gonadal ridges form, the basement membrane degenerates and two types of cells invade:
- Mesenchymal from intermediate mesoderm (coelomic epithelium-derived cells)
- PGC - Primordial germ cells
Germ cells get to the genital/gonadal ridge via the _______
Germ cells get to the genital/gonadal ridge via the dorsal mesentery
PGCs (primordial germ cells) originated very early from the ______ but then moved into the _____ to avoid _______
PGCs (primordial germ cells) originated very early from the epiblast but then moved into the yolk sac wall to avoid gastrulation
PGCs (primordial germ cells) migrate from yolk sac, through the ____ to ______ during week 4-6 (following ________cues) where they colonize _______
PGCs (primordial germ cells) migrate from yolk sac, through the GI tract/dorsal mesentery to dorsal body wall during week 4-6 (following attracting cues - active migration) where they colonize gonadal ridges
The interior of the gonadal ridge is invaded by ________ coming from the intermediate mesoderm around the ________, dividing the ________ cells into columns called the ________
• A new basement membrane will form and maintain a division between ________ and ________
The interior of the gonadal ridge is invaded by mesenchyme coming from the intermediate mesoderm around the mesonephros, dividing the somatic support cells into columns called the primary sex cords.
• A new basement membrane will form and maintain a division between somatic support cells and mesenchyme
Label
In both males and females, new ducts appear adjacent to mesonephric ducts, these are the _________
In both males and females, new ducts appear adjacent to mesonephric ducts, these are the Mullerian ducts/paramesonephric ducts
The Mullerian ducts follow the mesonephric ducts _____ toward the _______
However, the growing Mullerian ducts ______ before _______
The Mullerian ducts follow the mesonephric ducts caudally toward the urogenital sinus
However, the growing Mullerian ducts join together before fusing with the urogenital sinus
Mullerian duct starts as _______ of the _________
It then extends _______
What is significant about the cranial end of the mullerian duct?
Mullerian duct starts as an invagination of the coelomic epithelium (wraps around groove to form duct)
It then extends caudally alongside the mesonephric duct
What is significant about the cranial end of the mullerian duct? The cranial end is open to the intraembryonic coelom (= fallopian tube)
Expression of the SRY transcription factor in male support cells drives their differentiation into ______ largely through activation of ______
Expression of the SRY transcription factor in male support cells drives their differentiation into Sertoli cells largely through activation of SOX9
Cells from coelomic epithelium (gpc) in the genital ridge turn on ______ which drives differentiation of those cells to become Sertoli cells through activation of _______
Cells from coelomic epithelium (gpc) in the genital ridge turn on SRY which drives differentiation of those cells to become Sertoli cells through activation of SOX9
Developmental functions of Sertoli Cells:
- Expansion of _______ into ______
- Secrete _______
- Drive differentiation of ______
- Control _____ (inhibit ____ and ____)
Developmental functions of Sertoli Cells:
- Expansion of primary sex cords into testis cords (earliest morphological sign of testis differentiation)
- Secrete Anti-Mullerian Hormone (AMH)
- Drive differentiation of Leydig cells
- Control Germ cells (inhibit mitosis and meiosis)
_____ are enclosed within the testis cords
Sertoli cells inhibit ____ and ______ of germ cells
PGCs (progenitor Germ Cells) are enclosed within the testis cords
Sertoli cells inhibit mitosis and meiosis of germ cells
Testes cords mature into ______ but do not develop a _____ until puberty
Testes cords mature into seminiferous tubules but do not develop a lumen until puberty
What happens to PGCs 3 months postnatally?
Further mitosis, meiosis and spermatogenesis all occur starting at puberty in response to ______
3 months postnatally, PGCs differentiate into type of spermatogonia (ie sperm stem cells)
Further mitosis, meiosis and spermatogenesis all occur starting at puberty in response to testosterone
What is the function of AMH (Anti-mullerian hormone) and what secretes it?
Sertoli cells secrete AMH which causes degeneration of Mullerian ducts
Leydig cells secrete ________
Promotes:
Leydig cells secrete androgens (eg testosterone)
- Promotes (phenotypic sex development)
- differentiation of the mesonephric duct into the epididymis and vas deferens
- Development of male urethra, prostate penis and scrotum
- testicular descent (into the scrotum)
Leydig cells secrete androgens (eg testosterone) which promotes:
- differentiation of the ________ into the ________ and ________
- Development of ________, ________ and ________
- ________ (into the ________)
Leydig cells secrete androgens (eg testosterone) which promotes:
- differentiation of the mesonephric duct into the epididymis and vas deferens
- Development of male urethra, prostate penis and scrotum
- testicular descent (into the scrotum)
Sertoli cells make _____ and _______ (of the sperm pathway)
Sertoli cells make seminiferous tubules and rete testis (of the sperm pathway)
Efferent ductules come from ________
Efferent ductules come from mesonephric tubules
Contribution of mesonephros to male reproductive tract:
- Mesonephric duct forms ______ and _______
- Mesonephric tubules form the ______ connecting the ____ to the _____
Contribution of mesonephros to male reproductive tract:
- Mesonephric duct forms epididymis and vas deferens
- Mesonephric tubules form the efferent tubules connecting the testes to the epididymis
- At first, gonadal ridge is just a protrusion of ______ into the coelom
- In order to separate gonad from body cavity, a _______ forms around it = the _______
- At first, gonadal ridge is just a protrusion of coelomic epithelial cells into the coelom
- In order to separate gonad from body cavity, a thick connective tissue layer forms around it = the tunica albuginea
All of the male accessory glands form as _______
All of the male accessory glands form as outpouchings of other structures:
- Mesonephric ducts → seminal vesicles/gland (mesodermal)
- pelvic segment of urogenital sinus → prostate and bulbourethral glands (endodermal)
All of the male accessory glands form as outpouchings of other structures:
- Mesonephric ducts → _________
- pelvic segment of urogenital sinus → _________
All of the male accessory glands form as outpouchings of other structures:
- Mesonephric ducts → seminal vesicles/gland (mesodermal)
- pelvic segment of urogenital sinus → prostate and bulbourethral glands (endodermal)
All of the male accessory glands form as outpouchings of other structures:
- _________ → seminal vesicles/gland (mesodermal)
- __________ → prostate and bulbourethral glands (endodermal)
All of the male accessory glands form as outpouchings of other structures:
- Mesonephric ducts → seminal vesicles/gland (mesodermal)
- pelvic segment of urogenital sinus → prostate and bulbourethral glands (endodermal)
Gonads are initially anchored by 2 ligaments:
- ______ to diaphragm
- _______ to perineum
Gonads are initially anchored by 2 ligaments:
- cranial suspensory ligament to diaphragm
- gubernaculum to perineum
Which ligament degenerates to allow for testicular descent?
The cranial suspensory ligament → which connects the testes to the diaphragm
Which ligament guides the testes through the inguinal canal?
Gubernaculum
Testicular descent happens in two phases:
- Gubernaculum swells and anchors testis near the site of the future inguinal canal (weeks 10-15)
- Gubernaculum actively descends into the scrotum bringing the testis (weeks 25-35)
During testicular descent, an evagination of body cavity (sac of peritoneum) descends into scrotal sac called the _________ - eventually must close
During testicular descent, an evagination of body cavity into scrotal sac forms called the processus vaginalis
25-35: what happens to the processus vaginalis?
What sort of cavity (collapsed sac) remains?
25-35: what happens to the processus vaginalis? closes postnatally
What sort of cavity (collapsed sac) remains? Tunica vaginalis
What happens if the cranial portion of the processus vaginalis is not fully obliterated?
May be left with cysts or an opening for an indirect inguinal hernia
What is cryptorchidism?
How might it be treated?
Risks?
Failure of testes to descend into scrotum
Treated hormonally
Repaired surgically (orchiopexy) if don’t descend by 6 months
Risk factor for infertility and testicular cancer if not repaired
How does the genital ridge differ in males and females?
The genital ridge starts the same, created by _______
- difference in females: no _______
The genital ridge starts the same, created by proliferation of coelomic epithelium.
difference in females: no SRY = no sertoli cells
- in the absence of sertoli cells, PGCs proliferate rapidly until differentiating into oogonia
The genital ridge starts the same in females and males, created by the proliferation of coelomic epithelium.
the difference in females: no SRY = no sertoli cells
- in the absence of sertoli cells: PGCs _______ until differentiating into ______
The genital ridge starts the same in females and males, created by the proliferation of coelomic epithelium.
the difference in females: no SRY = no sertoli cells
- in the absence of sertoli cells: PGCs proliferate rapidly until differentiating into oogonia
Ovarian development:
- The _______ break down into clumps of oogonia (egg stem cells) surrounded by ________
- Oogonia enter meiosis, but arrest in _______ (now ________)
Ovarian development:
- The primary sex cords break down into clumps of oogonia (egg stem cells) surrounded by somatic support cells
- Oogonia enter meiosis, but arrest in first metaphase (now primary oocytes)
- The ______ drive differentiation of the support cells into follicle cells that will become arranged into single cell layers surrounding individual primary oocytes giving rise to ________
The primary oocytes drive differentiation of the support cells into follicle cells (granulosa cells) that will become arranged into single-cell layers surrounding individual primary oocytes giving rise to primordial follicles
Fate of the female Mullerian and Mesonephric (wolffian) ducts:
- No testosterone (no leydig cells) = degradation of _______
- No ____ = Mullerian ducts persist and develop into _____ and _______
Fate of the female Mullerian and Mesonephric (wolffian) ducts:
- No testosterone (no leydig cells) = degradation of mesonephros (wolffian ducts)
- No AMH (no sertoli cells) = Mullerian ducts persist and develop into _____ and _______
Mullerian ducts fuse with _____
Origin of the vagina is unclear- may be formed by ____ or _____ or have contributions from both
Mullerian ducts fuse with urogenital sinus
Origin of the vagina is unclear- may be formed by mullerian ducts or urogenital sinus or have contributions from both
The ______ divides pelvis between bladder and rectum
The broad ligament divides pelvis between bladder and rectum
How is the broad ligament formed?
Due to formation, where are the ovaries in relation to the broad ligament?
- As the mullerian ducts zipper together, they swing the urogenital ridges medially and away from the posterior body wall
- pulls two folds of peritoneum together to create the broad ligament
- ovaries end up posterior to the broad ligament
________ fuse to form the uterus
paramesonephric ducts fuse to form the uterus
What is the mystery anatomy?
Primitive phallus capped by genital tubercle → forms in both males and females
Label:
Genital tubercle (caps primitive phallus) forms the ______
Genital tubercle (caps primitive phallus) forms the glans penis/clitoris
The phallic segment differs from the pelvic segment how (of the urogenital sinus)
The phallic segment isn’t a hollow tube like the pelvic segment
It forms a fin of endoderm (urethral plate) protruding into the primitive phallus
The phallic segment isn’t a hollow tube like the pelvic segment (of urogenital sinus)
It forms a fin of _______ (called the _______) protruding into the ________
The phallic segment isn’t a hollow tube like the pelvic segment
It forms a fin of endoderm (urethral plate (M)/vestibular plate(F)) protruding into the primitive phallus
What is the urethral/vestibular plate?
Urethral plate (males) or vestibular plate (females) is a solid ridge of endoderm that runs along the ventral midline of the primitive phallus as an extension of the urogenital sinus
The urethral plate opens to form the ______ (males)
Same thing happens in females but its called the vestibular plate and it opens to form the _______
The urethral plate opens to form the urethral groove (males)
Same thing happens in females but its called the vestibular plate and it opens to form the vestibular groove
What is different about the urethral and vestibular grooves?
The urethral groove opens and then closes
The vestibular groove remains open
How does the urethral groove close and what does it become?
Urethral folds fuse around the groove
Now the penile urethral tube lined with endoderm
What is hypospadias and how is it caused?
Hypospadias is a urethral opening on the ventral side of the penis caused when the urethral folds do not close properly
- opening can be anywhere along the ventral surface but most common is at junction between shaft and glans
The female vestibular folds remain unclosed:
Between the vestibular folds is the ______ into which both the urethra and vagina open
The female vestibular folds remain unclosed:
Between the vestibular folds is the vestibule of the vagina into which both the urethra and vagina open
The female vestibular folds remain unclosed:
Between the vestibular folds is the vestibule of the vagina into which both the _____ and _____ open
The female vestibular folds remain unclosed:
Between the vestibular folds is the vestibule of the vagina into which both the urethra and vagina open
Unfused vestibular folds = _____
Unfused vestibular folds = labia minora
Unfused genital swellings =
unfused genital swellings = Labia majora
Male and female external genitalia have analogous components: similar _____ and ______
Female structures are just less _____ and more ______
Male and female external genitalia have analogous components: similar erectile tissue and surrounding muscles
Female structures are just less prominent and more divided
