Reproductive Histology/Development Flashcards
function of testis
produce androgens (testosterone) and gametes (spermatozoa)
function of excurrent ducts (epididymis, ductus/vas deferens)
maturation of sperm and transport to prostatic urethra
layers of testis
- albuginea = outer
- vasculosa = inner
- septa = separate seminiferous tubules
what enters/exits the mediastinum of testis?
- blood vessels
- lymphatics
- rete testis
pathway of sperm
seminiferous tubules –> tubuli recti (straight) –> rete testis –> efferent ductules/epididymis –> vas deferens
Leydig cells
- found in testicular interstitium
- produce testosterone (male development)
- euchromatic cells - active, pale
function of testosterone
- male development
- development of sperm in seminiferous tubules
- regulated by LH (receptors on leydig cells)
layers of seminiferous tubules
- lamina propria (fibroblasts, collagen)
- seminiferous epithelium (sertoli, spermatogenic)
Sertoli cells
- irregular euchromatic nucleus
- junctional complexes and cell junctions
- nourish and help move germ cells
- structural support via cytoskeleton - divides epithelium into basal (immature) and adluminal (mature) compartments
- ABP, inhibin, phagocytose ability
tight (occluding junctions in Sertoli cells)
- no fluid passage
- disassemble and reassemble to maintain structure but allow movement
- blood-testis barrier –> immune privileged site
what happens with damage to tight junctions?
immune cells enter –> mount a response against the sperm
role of antigen binding protein
- produced by Sertoli cells
- binds testosterone in seminiferous tubules for spermatogenic cells
- FSH dependent
- maintains or increases levels of testosterone if needed
role of inhibin
-inhibits FSH release when having excess testosterone
spermatogonia
immature germ cells
-heterochromatin
spermatogenesis
spermatogonia –> 1,2 spermatocytes –> spermatids –> spermatozoa
what cells divide by mitosis?
spermatogonia
what cells divide by meiosis?
primary and secondary spermatocytes
type A dark spermatogonia
- mitosis
- dark, ovoid nucleus
- precursors - produce clones
type B pale spermatogonia
- mitosis
- pale, euchromatic ovoid nucleus
- produce type B cells
- cytoplasmic bridges for synchronous development when differentiating
type B spermatogonia
- formed from type A pale
- round nucleus
- most mature
- differentiate into spermatocytes
primary spermatocytes
- meiosis I (22 days), large cells
- why there are most abundant in histo slide
secondary spermatocytes
-meiosis II (fast), small cells
spermiogenesis
spermatids –> spermatazoa
- Golgi phase
- cap phase
- acrosome phase
- maturation phase
hydrolytic enzymes
- formed from proacrosomal granules
- allows sperm to penetrate ovum
function of axoneme
- formed from centrioles
- forms flagellum core - dynein arms use ATP to propel sperm
function of acrosomal cap
attaches to nuclear envelope
what is manchette?
- sheath on posterior part of nucleus
- helps elongate spermatid
function of pampiniform plexus
- rich in veins and surround the testicular artery
- counter-current heat exchanger
- maintains proper temp in testis for sperm development
cryptochordism
- undescended testis
- temp. in abdomen too high –> cannot make sperm
- bilateral undescended testis –> serile
mediastinum
- connective tissue that contains rete testis
- posterior side of testis
seminiferous tubules
- sperm development
- Sertoli cells
tubuli recti (straight tubules)
-transition to simple cuboidal epith.
rete testis
- found w/I mediastinum
- simple cuboidal epith.
efferent ductules
- coiled
- connect rete testis to epididymis
- thin muscle
- ciliated pseudo stratified columnar epith. (saw tooth)
ductus/vas deferens
- folded mucosa, thick muscle, adventitia
- pseudostratified columnar (microvilli)
when does sperm become motile?
when reaching the epididymis
prostate
- pseudostratified columnar epith.
- tubuloalveolar glands
- corpora amylacea - calcified concretions
- transitional and peripheral zone
seminal glands
- viscous fluid containing sugar (fructose) and prostaglandins –> nourish sperm
- tortuous
- mucosa, muscularis, fibrous coat
- pseudostratified columnar or cuboidal epith.
- smooth muscle contraction during ejaculation brings fluid into ejaculatory duct and prostatic urethra
ductus epididymis
- basal cells (stem)
- principle cells (absorption, sperm maturation & motility)
ductus epididymis
- basal cells (stem)
- principle cells (absorption, sperm maturation & motility)
- stereocilia (better absorption)
- pseudostratified epith.
ductus epididymis
- basal cells (stem)
- principle cells (absorption, sperm maturation & motility)
- stereocilia (better absorption)
- pseudostratified epith.
transitional zone of prostate
mucosal glands
transitional zone of prostate
- mucosal glands
- anterior and middle lobes
peripheral zone of prostate
- 70%
- main prostatic glands
- posterior and lateral lobes
peripheral zone of prostate
- 70%
- main prostatic glands
- posterior and lateral lobes
what regulates prostate secretions?
testosterone levels
- high test –> high secretions
- low test –> low secretions
benign prostatic hyperplasia
- associated with transitional zone (mucosal glands increased)
- compression of urethra –> micturition and urine retention problems
prostatic adenocarcinoma
- associated with peripheral zone
- advanced when signs are noticed - takes longer to compress prostatic urethra
bulbourethral “Cowper’s” glands
- lubricating function - mucous glands
- open into penile urethra
corpora cavernosa & corpus spongiosum
-vascular spaces with smooth muscle that run the length of the penis
what arteries are found in corpora cavernosa?
-central arteries
what is found in the corpus spongiosum?
- penile urethra with mucous glands (Littre)
- also helps form the glans penis
role of tunica albuginea
- fibroelastic
- holds penis together during erections
- surrounds both cavernosa and spongiosum
blood supply to penis
- dorsal artery
- urethral arteries
- artery of the bulb
- deep arteries (nutritive and helicine)
broad ligament
folds of peritoneum that cover pelvic viscera
- mesosalpinx
- mesovarium
- mesometrium
follicles
composed of an oocyte surrounded by one or more epithelial cells
-found w/I cortex
primordial follicle
- earliest stage of follicle development
- only ones before puberty
- primary oocyte and squamous cell
what is released for follicular growth of primordial follicles?
FSH
cuboidal (unilaminar) and stratified (multi-laminar) epithelium
-occurs when primordial follicle proliferates after being stimulated by FSH
what do stromal cells surrounding epithelium differentiate into?
theca folliculi
- interna –> steroid production
- externa –> smooth muscle to expel oocyte
unilaminar follicles
- single cuboidal cells
- zona pellucida (glycoproteins) b/w oocyte and follicle
- ZP2,3 –> binding of sperm; release of acrosome enzymes
- ZP1 –> cross-link remaining ZP2,3 to prevent further binding of sperm
function of ovastacin
break down ZP2 to prevent further binding of sperm if fertilization occurs
multilaminar follicles
- proliferation of follicular cells surrounding oocyte due to activin
- activin = release of FSH and binding to receptors
- growth factors (BMP-15, GDF-9) proliferate follicular cells forming granulosa cells
- theca folliculi begin to form
polycystic ovarian syndrome
- enlarged ovaries with cysts
- increased androgens
- irregular periods
- common cause of infertility
- causes: excess insulin, low grade inflammation, hereditary
- treat: weight loss, birth control pills
secondary follicles
- follicles contain fluid filled cavities to form antrum
- theca interna (secrete androstenedione) and externa (fibroblasts and smooth muscle) are developed
aromatase
convert androstenedione to estradiol in the granulosa cells
- androstenedione from the theca interna
- estrogen returns to theca and storm to enter bloodstream
mature Graafian follicles
- larger than secondary follicle
- oocyte displaced to one side, larger antrum
- contain corona radiata (layers of follicles around oocyte)
ovulation
rupture of mature/Graafian follicle and release of ovum
- controlled by LH (release of oocyte)
- oocyte, corona radiata, follicular fluid expelled
function of corpus luteum
remnant of follicle
- produces progesterone, inhibin, and estrogen for negative feedback on hypothalamus and pituitary
- no fertilization –> forms corpus albicans (scar tissue)
follicular (functional) cysts
produced by late primary or antral follicles
- high estrogen levels and menstrual irregularities
- disrupt blood vessels –> hemorrhagic cysts
atresia
degenerative process of ovarian follicles
- death of granulosa cells, loss of corona radiata, oocyte floating freely in antrum
- degeneration by dominant follicle releasing inhibin after ovulation shutting down FSH production
corpus luteum
residual/remnant of dominant follicle after ovulation
- formation is LH dependent
- formed from granulosa and theca cells undergoing luteinization to become lutein cells
- fertilization –> predominant source of steroids
- no fertilization –> regress to corpus albicans (scar tissue)
2 types of lutein cells in corpus luteum
- granulosa lutein
- secrete progesterone and estradiol by FSH, LH stimulation
- lack enzymes for estradiol synthesis - theca lutein cells provide androstenedione to convert to estradiol in granulosa - theca lutein
- secrete progesterone and androstenedione by LH stimulation
role of progesterone
maintain endometrium of uterus (secretory/luteal phase)
-action blocked by mifepristone
uterine tubes
- site of fertilization
- travel of preimplanted embryo to uterus
- luminal folds decrease as you move towards uterus
layers:
1. infundibulum = opening near ovary; fimbriae capture oocyte
2. ampulla = largest; where fertilization occurs
3. isthmus = narrow; b/w ampulla and isthmus
4. intramural = contained w/I uterine wall
histologic layers of uterine tube
- mucosa = epithelium + lamina propria
- secretory (principle) cells = conciliated; nutrients for nourishment
- ciliated cells = cilia move embryo towards uterus - muscularis = smooth muscle; peristalsis contractions
- serosa = simple squamous
Salpingitis
bacterial infection (neisseria gonorrhea or chlamydia)
- result of STIs
- scaring of uterine tube –> ectopic pregnancy
- epith. surrounded by neutrophils
3 regions of uterus
- body - below entrance of uterine tube
- fundus - above entrance
- cervix - inferior; enters vagina; associated w/ cancer
3 layers of uterine wall
- endometrium - simple columnar; endometrial glands
- basal layer = regenerates functional layer during menstrual cycle; never degenerates
- functional layer = changes during menstrual cycle; does degenerate - Myometrium = smooth muscle; contraction by oxytocin and PGE
- contains statum vasculare = blood supply to endometrium - Perimetrium = connective tissue
menstrual phase (days 1-4)
- necrosis and shedding of functional layer of endometrium
- rupture of spiral arterioles causing hemorrhage –> lose glands, stroma, blood vessels
proliferative (follicular) phase (days 4-15)
- regeneration of functional layer
- controlled by estrogen from granulosa cells of secondary and Graafian follicle
- straight endometrial glands and stroma**
ovulatory phase (days 14-16)
- ovulation of secondary oocyte arrested in meiosis II
- peak levels of LH (LH surge) caused by estrogen
secretory (luteal) phase (days 15-25)
- secretion by endometrial glands (ready for implantation)
- controlled by progesterone from granulosa lutein cells of corpus luteum
- tortuous (convoluted) glands filled with secretions
- where leftover follicle gives rise to corpus luteum
premenstrual phase (days 25-28)
starting over
- ischemia induced
- reduce progesterone and estrogen bc no fertilization occurred –> form corpus albicans
Endometriosis
endometrial tissue outside uterus
- infertility, dysmenorrhea, pelvic pain
- gunpowder mark lesions
- blood-filled (chocolate) cysts on ovaries
Leiomyomas
fibroids, benign tumors w/I myometrium
- subserosal, intramural, submucosal
- protrude on uterus or enter cavity
cervix
- supravaginal (above vagina) and vaginal (protrude into vagina) portions
- ectocerix = speculum –> PAP smear; stratified squamous, nonkeratinized
- endocervix = contains external/internal os (openings of cervical canal); simple columnar, keratinized; site for cervical cancer in transition zone
histology of cervix
- simple columnar; mucous secreting cervical glands
- epith. and glands not affected by menstrual cycle
- watery mucous in proliferative phase –> sperm travel
- viscous mucous in secretory phase –> block sperm
what does relaxin due during childbirth?
softens the cervical connective tissue
-produced by placenta and ovary
cervical carcinoma
common; associated with HPV
- originates from stratified squamous, non-keratinized epithelium (transition zone)
- in situ = stays localized, no travel
- invasive = metastasize
- exfoliate cytology = Pap smear to look at abnormal cells
vaginal layers
- mucosa
- nonkeratinized stratified squamous epith. & lamina prop.
- superficial layer exfoliation during menstrual cycle
- accumulate glycogen due to estrogen –> acidic vagina by lactic acid –> prevents invasion of bacteria/fungi - muscularis
- smooth muscle; elastic fibers to give vagina distensibility - adventitia - connective tissue
vaginitis
inflammation of vagina –> discharge, pain
- trichomonas vaginalis = sexually transmitted protozoa,, strawberry mucosa, odorous white discharge
- candida albican = fungus (yeast), cottage cheese discharge
- gardnerella vaginalis = high levels of bacteria, fish smell discharge
breast tissue
- suspensory (Cooper) ligament
- adipose tissue
- mammary glands
- develop ducts and alveoli w/ pregnancy
nipple
- keratinized stratified squamous epith.
- contract smooth muscle –> milk ejection
- dermal papillae –> capillaries giving it pink color
- becomes darker during puberty
areola
- sebaceous glands (Montgomery tubercles)
- darker color during puberty
- sensory innervation (sucking) - ejection of milk by oxytocin
mammary gland
- made up of tubuloalveolar glands
- alveoli –> lactiferous ducts –> lactiferous sinus (milk reservoir)
prepuberty and puberty breasts
- duct system embedded in fibrocollagenous tissue
- downgrowths develop forming ducts, no alveoli or lobules present
- proliferation of fat cells by estrogen –> increase size
mammary glans, non pregnant
- small ducts, few lobules (contain alveoli that make secretions)
- connective tissue and fat
breast during pregnancy
- more lobules, less connective tissue
- growth of duct system by progesterone & estrogen
- alveoli secrete colostrum
breasts during lactation
- alveoli –> milk production
- oxytocin –> milk ejection
- prolactin inhibiting hormone, dopamine –> inhibited and cause release of PRL
breast cancer
- invasive ductal carcinoma = most common; damage mammary gland ducts and surrounding tissue
- ductal carcinoma in situ = noninvasive; only affects mammary gland ducts
BRCA1,2 genes
human tumor suppressor cells - mostly in breast cells
- force cells into apoptosis if DNA is damaged
- mutations –> susceptible to breast, prostate, ovarian cancer
where do primordial germ cells originate?
umbilical vesicle
- migrate to gonadal ridge 5th week
- become gonadal ridge forming sperm or egg
gonadal cords
invaginate into the mesonephros forming medulla for later germ cell entry
what does the Cortex of gonadal ridge form?
testes
what does the medulla of gonadal ridge form?
ovary
when does differentiation b/w male & female occur?
week 7
- indifferent before that
- separation from testes or ovary from mesonephros
testes determining factor (TDF)
signal for gonads to develop into testes
- in SRY gene on Y chromosome
- form rete testis and seminiferous tubules
Leydig cells
- found w/I in interstitium
- secrete testosterone and androstenedione for male development
Sertoli cells
- found w/I seminiferous cords
- secrete AMH to inhibit female development
what is the default of gonadal development?
female
-when no TDF is present
female development
- gonadal cords and rete ovarii degenerate
- form cortical cords which form primordial follicles for oogenesis
mesovarium vs. mesorchium
mesovarium = suspend ovaries mesorchium = suspend testes
mesonephric (wolffian) duct
male development
paramesonephric (mullerian) duct
female development
-fusion forms uterovaginal primordium which forms sinus tubercle when reaching urogenital sinus
AMH hormone
causes paramesonephric duct regression –> no female development
-released from Sertoli cells in testes
mesonephric duct in males
- proximal –> epididymis
- tubular portion –> efferent ductules
- distal –> vas deferens (some smooth muscle)
what forms the ejactulatory duct in males?
connection b/w seminal gland and vas deferens
what male structure is formed from urogenital sinus?
bulbourethral gland
layers of prostate
- prostatic urethra (urogenital sinus origin)
- outgrowths form prostate gland - surrounding mesenchyme
- form stroma and smooth muscle
female development
- paramesonephric duct
- no AMH or TDF (hormonal signaling)
- cranial –> uterine tube
- uterovaginal primordium –> forms uterus
sinus tubercle
formed from contact b/w uterovaginal primordium and urogenital sinus
-form sinovaginal bulb –> vaginal plate –> vagina
genital tubercle
formed from the primordial fallus
-form penis or clitoris
labioscrotal swellings
form labia major in females or scrotum in males
male external genitalia
- closure of urethral folds –> spongy urethra
- ectodermal cord forms in glans penis
- fusion of ectodermal cord + spongy urethra –> full urethra
- mesenchyme –> erectile tissue (cavernosa, spongiosum)
female external genitalia
- no fusion of urethral folds –> labia minora
- unfused labioscrotal swellings –> labia majora
inguinal canal
- allows relocation of testes
- both genders
gubernaculum
ligament that attaches to gonad and labioscrotal swelling
- moves testes or ovary inferiorly
- formed as meso/paramesonephros degerates
- upper portion (female) –> ovarian ligament
- lower portion (female) –> round ligament
processus vaginalis
- invaginates peritoneum
- push other layers aside to make room for gonad
2 phases of testicular descent
- trans abdominal movement (b/w 10 & 26 weeks)
- abdomen elongates away from pelvis - inguinoscrotal movement (begins 26 week)
- hormonally controlled
what happens if fusion of paramesonephric duct fails?
double uterus
-double vagina
failed fusion at superior end of paramesonephric duct?
bicornuate uterus
-rudimentary horn from slow development of one paramesonephric duct
normal externally, but has a thin septum internally?
divided uterus
what happens if one paramesonephric duct fails to develop?
unicornuate uterus
hypospadias
external urethral orifice on ventral side
- glanular (most common) = ventral side of glans penis
- penile = ventral side of penis
- penoscrotal = junction of penis and scrotum
- perineal = labioscrotal swellings do not fuse, external urethral orifice b/w unfused halves
hyperspadias
external urethral orifice on dorsal side
result if proximal portion of processes vaginalis persists?
incomplete congenital inguinal hernia
result if entire processes vaginalis persists?
complete congenital inguinal hernia
result if middle processes vaginalis remains and contains fluid?
hydrocele of spermatic cord
result if entire processus vaginalis remains and contains fluid?
scrotal hydrocele
cryptorchidism
- hidden testes
- failure to descend
- can lead to infertility
