Genital System Flashcards
1) What is the difference btw gender genotype and gender phenotype?
2) What occurs during the indifferent stage in genital development
3) What can occur during this stage?
1) Gender genotype - inherited
gender phenotype - consequence of hormones released during embryonic development by gonad (determined by genotype)
2) gonads, genital ducts and external features are the same in both sexes
3) genital anomalies involve combination of intersex development and appearance
1) What is the gonadal ridge?
2) What originates from it?
3) What is the gonad composed of?
4) What do supporting cells form and where do they come from?
5) Where do germ cells arise from and what occurs?
6) What must occur to germ cells otherwise what will happen?
1) a thickening of intermediate mesoderm plus coelomic mesothelium that develops medial to mesonephric kidney
2) gonads
3) germ cells and supporting cells
4) form cellular cords (gonadal cords) that radiate into gonadal ridge –> cells arise from invading mesothelium and disintegrating mesonephric tubules
5) arise from yolk sac endoderm –> migrate along gut wall and mesentery to reach gonadal ridge –> induces further gonadal development
6) proliferate and MUST migrate inside gonadal cords so they are surrounded by supporting cells –> failure to do so involves degeneration
1) What are gonadal cords called in the testis?
2) What happens to germ cells in the male?
3) What occurs at puberty to seminiferous cords?
4) What happens to deep cords that lack germ cells?
5) What happens to the supporting cells?
6) What are sustentacular cells?
7) What are interstitial cells?
8) What are the fns of each population?
9) What does the the mesothelium covering the testis become?
10) What does the mesenchyme deep to the mesothelium become?
11) What do androgen hormones do?
1) they hypertrophy and are called seminiferous cords
2) germ cells within seminiferous cords differentiate into spermatogonia and become dormant
3) become canalized –> seminiferous tubules; spermatogonia initiate spermatogenesis
4) become tubules of the rete testis (located centrally in testis)
5) differentiate into sustentacular cells (sertoli cells) and interstitial cells
6) located in wall of seminiferous tubules; secrete inhibitory factors –> suppress spermatogenesis and female duct development
7) located outside seminiferous tubules –> become two populations
8) one population produces androgen hormones immediately; other pop. delays androgen production untill sexual maturity
9) visceral peritoneum
10) tunical albuginea
11) stimulate male genitalia development
1) What happens to gonadal cords in female?
2) How are primordial follicles formed?
3) What happens to the germ cells in female?
4) When is meiosis completed?
5) When is follicle and germ cell proliferation completed?
6) True or False: lifetime allotment of primary oocytes is already present in neonatal ovary
7) What happens to germ cells if they fail to become incorporated within follicle?
1) undergo reorganization
2) individual germm cells are surrounded by a sphere of flat supporting cells
3) germ cells = oogonia differentiate into primary oocytes that start meiosis but remain stuck in prophase of meiosis I (surrounding cell inhibit meiosis)
4) at ovulation in adult
5) in utero
6) True
7) they degenerate (90% of germ cells complete meiosis and then degenerate —> to reduce, meiosis onset is delayed in embryos of species havign longer gestation)
1) True or False: in the indifferent stage, each sex has their own gential ducts and a urogenital sinus
2) What are the female genital ducts?
3) What are the male genital ducts?
4) What happens with the mesonephric duct in this stage?
5) Describe development of paramesonephric duct?
6) Which hormone determines which duct system develops?
7) What does the male duct require for development?
8) What is the female duct suppressed by?
1) False, both sexes at this stage have male and female genital ducts and a urogential sinus
2) paramesonephric duct or mullerian ducts
3) mesonephric duct or wolffian ducts
4) they persist after mesonephros disintegrates
5) develops along ventrolateral coelomic surface of mesonephros (begins as groove –> core of cells –> canalizes and elongates)
6) testicular hormones
7) testosterone produced by interstitial cells
8) inhibitory hormone released by sustentacular cells
1) What happens in the absence of testosterone?
2) What does the cranial region of the paramesonephric duct form?
3) What does the paramesonephric duct become caudal to inguinal fold (gubernaculum)?
4) What happens caudally to this portion?
5) What do they form?
6) What is species dependent in females?
7) Describe species examples
1) mesonephric ducts fail to develop (remnants found in wall of vestibule)
2) cranial reigion of duct remains open and forms uterine tube
3) each duct becomes a uterine horn
4) bilateral ducts shift medially and fuse into a single tube that ends blindly in contact with urogential sinus
5) become uterine body, uterine cervix and cranial third of vagina
6) degree of paramesonephric duct fusion
7) fusion greatest in horses, least in carnivores
- primates –> uterine body w/o horns
- rodents and rabbits –> double uterus (2 cervices enter single vagina)
- monotremes and many marsupials –> double vagina (no fusion at all)
1) What is unique about the vagina?
2) Where does the cranial one-third come from?
3) What does the cranial two-thirds come from?
4) Describe steps of #3
5) What may persist where vagina joins urogenital sinus
6) Is this commonly present in our domestic mammals?
1) has a dual origin
2) fused paramesonephric duct
3) from outgrowth of future vestibule
4) -site where fused ducts contact urogenital sinus –> solid tubercle (vaginal plate) grows outward from future vestibulle
- degeneration of center of solid tubercule –> vaginal lumen
5) hymen
6) no
1) What happens due to presence of inhibitory hormone?
2) What do some mesonephric tubules become?
3) What happens to cranial region of duct?
4) What happens to remainder of duct?
5) Where does the duct empty?
1) paramesonephric ducts regress due to hormone produced by sustentacular cells of testis (remnants often evident in adult male horse as a uterus masculinus)
2) efferent ductules (already communicate with mesonephric duct but must establish communication with rete testis
3) undergoes extensive elongation and coiling –> epididymis
4) enlarges –> ductus deferens
5) into region of urogenital sinus that becomes pelvic urethra
1) How do prostate and bulbourethral glands develop?
2) What are vestibular glands are female homologues of what?
3) Where do vesicular glands arise as?
4) Where does gland smooth muscle come from?
1) develop in typical gland fashion by outgrowths of urogenital sinus endoderm
2) male bubourethral glands
3) an epithelial outgrowth from caudal region of mesonephric duct (mesoderm)
4) surrounding mesenchyme
1) What is the gubernaculum?
2) What happens to the gubernaculum?
3) What is the gubernaculum resposible for?
4) What pulls the testis to the inginual canal?
5) What forces testis through canal into scrotum?
1) prpoduced by condensation of mesenchyme within inguinal fold (runs along body wall linkign the gonad to the inguinal region)
2) accumulates fluid and becomes a gel mass as large in diameter as a testis (under influence of gonadotropins and testicular androgens)
3) swollen gubernaculum –> preclude closure of body wall and is responsible for formation of inguinal canal and vaginal process (coelom evagination)
4) subsequent outgrowth of scrotal wall and dehydration of gubernaculum
5) sudden increase in intra-abdominal pressure
1) In both genders, what happens in relation to the gonad?
2) What happens to the ovaries in females?
3) What happens to the testes in males?
1) there is some caudal shift of the gonad from its original position due to elongation of the body and a variable degree of retention by inguinal fold derivatives that pull on the gonad
2) remains intra-abdominal and the extent of caudal shift is species dependent (slight in bitch, descent into pelvis in cow)
3) each testis descends to the inguinal region (scrotum)
1) What does the mesonephros leave behind after it degenerates?
2) What is the caudal extension of the genital fold called and where does it run?
3) What does it give rise to?
4) What do the genital and inguinal folds become?
5) What does the genital fold become in the female?
6) What does the inguinal fold become in the female?
7) What does the genital fold become in the male?
8) What does the inguinal fold become in the male?
1) a genital fold that persists to suspend the gonad and the genital duct system
2) called the inguinal fold and it runs along the body wall and into the inguinal region
3) to teh gubernaculum of the fetus
4) the male and female genital ligaments
5) the broad ligament (suspensory ligament of the ovary, mesovariam, mesosalpinx, and mesometrium)
6) proper ligament of the ovary and the round ligament of the uterus
7) the mesorchium adn mesoductus deferens
8) gubernaculum and the adult proper ligament of the testis and ligament of the tail of the epididymis
1) What are external genitalia derived from?
2) Name them, where they develop/located.
1) three different perineal swellings
2) bilateral urogential folds - border the urogenital orifice and elongate ventrally (folds are caudal end odf urogenital sinus)
- genital tubercle - develops at ventral commissure of urogenital folds
- bilateral genital (labioscrotal) swellings - located lateral to urogenital swellings
***in domestic mammals, these persist only in males, unlike primates, where the swellings develop in both sexes, forming major labia in females and scrotum in males
1) In the male, what happens to the genital tubercle?
2) What does it become?
3) what happens to the urogenital orifice and folds?
4) what do they form and what is created as a result?
5) What happens next?
6) What does this establish?
7) What does genital tubercle mesenchyme give rise to?
8) How is the prepuce formed?
9) What happens to the genital swellings?
1) growth at teh base of it generates an elongate phallus
2) becomes the glans at the tip of the phallus
3) they elongate ventrally along with the attached phallus
4) the folds form a urogenital groove –> penile uretha created when groove closes by medial merger of folds in proximal to distal sequence
5) opening at distal end of penile urethra (within original genital tubercle) is created by ectoderm invasion and canalization
6) establishes communication btw ectoderm exterior and endoderm interior of penile urethra
7) penile erectile tissue, tunica albuginea, smooth muscle and bone (carnivores)
8) when a ring of surface ectoderm invades into the mesenchyme of the free end of the phallus –> divides tissue into a penis encircled by preputial skin
(except in cat, phallus of domestic mammals elongates deep to skin of ventral body wall)
9) enlarge and merge at midline to form a single scrotum (2 compartments)
***scrotum initially overlies the gubernaculum and vaginal process in inguinal region –> then shifts cranially; remains caudal in cat and pig
1) What does the urogenital orifice become in females?
2) What does the genital tubercle become?
3) What does the urogenital folds become?
4) What do the genital swellings become?
1) the vulval cleft –> opens into the vestibule (urogenital sinus)
2) the clitoris
3) elongate, overgrow the tubercle and become labia of the vulva
4) disappear in female domestic mammals (but become major labia in primates)
1) In relation to mammary glands, what forms in both genders?
2) What develops periodically along the ridge?
3) What happens elsewhere?
4) What do the buds determine?
5) What do the buds develop into?
6) What occurs at each bud?
7) What happens next?
8) What is species dependent (besides # of buds)
9) what can happen sometimes in relation to multiple lactiferous ducts?
10) True or False: it is common for extra buds to develop and degenerate
11) Failure to degenerate results in what?
1) a mammary ridge of thickened ectoderm forms bilaterally from axillary region to the inguinal region
2) mammary buds
3) elsewhere, mammary ridge ectoderm regresses
4) the number and location of mammary glands
5) mammary glands (sheep/goat/mare = 2, cow = 4, queen = 8, bitch = 10, sow = 14)
6) ectoderm induces proliferation of underlying mesoderm and mesoderm induces epithelial cell proliferation (teat formation)
7) epithelial cell solid cords invade underlying mesoderm and eventually canalize to form epithelial lined lactiferous ducts
8) teh number of cell cord invasions and subsequent lactiferous duct systems per teat (sheep/goat/cow = 1, mare/sow = 2, queen = 6, bitch = 12)
9) multiple lactiferous ducts open into a pit (inverted nipple) that becomes a nipple following proliferation of underlaying mesoderm
10) True
11) sueprnumerary teats
