Lecture 36: Reproductive System Microanatomy Flashcards
what structures make up the female reproductive system
- ovaries
- Fallopian tubes
- uterus
- cervix
- vagina
- (placenta during pregnancy)
describe the histological structure of the ovary
- single outer layer of germinal epi
- DIRCT capsule tunica albuginea
- cortex –> oocyte and follicular development
- medulla –> loose CT w/ bv from hilum
what 4 hormones drive the histological changes of the female reproductive organs
- follicle stimulating
- leutinising
- oestrogen
- progesterone
where in the ovary are most of the ovarian follicles found
in the cortex
what cells in the CT stroma of the ovary will respond to the hormones e.g. oestrogen
fibroblasts
what are the 4 types of follicles that can be distinguished in ovary
- primordial
- primary
- secondary
- vesicular
what does an empty follicle become once the oocyte has been ovulated
corpus luteum
what is the major endocrine organ during the first few months of pregnancy and why
- corpus luteum
- b/c no placenta
what happens to corpus lute if there is no pregnancy
undergoes atrophy and becomes fibrotic to form corpus albicans
what happens to most follicles between utero and puberty
- lost through atresia
- ~4mil –> ~200K
describe primordial follicles
oocyte covered by single layer of flattened granulosa (follicle) cells which provide nutritional network and endocrine signalling
describe primary follicle
- growth stimulated by follicle stimulating hormone
- granulosa cells now cuboidal (will secrete progesterone and help convert precursor oestrogen into full oestrogen)
- layer of glycoproteins called Zona Pellucida separates oocyte from granulosa cells
describe secondary follicle
- ^ in cell layers
- zona granulosa
- theca cells which surround stroma and produce androgens (go on to form corpus luteum post ovulation)
- basement membrane separates theca cells from zona granulosa
what develops in a late secondary follicle
an antrum –> fluid filled cavity
describe a Graafian follicle
- presence of antrum
- pressure of antrum pushes some granulosa cells to periphery and others surrounding oocyte known now as cumulus cells (cumulus radiata)
- oocyte surrounded by cumulus cells = cumulus oocyte complex
what are theca cells derived from
fibroblasts
what is the effect of ^ oestrogen production by Graafian follicle
- causes LH surge
- which stimulates ovulation and development of corpus luteum
what happens as a result of LH surge
- collagenase activity ^
- continued ^ in follicular fluids and pressure
- thinning of ovarian cortex surrounding follicle
- stigma (bulge adjacent to follicle forms)
- follicle ruptures releasing COC to be taken up by fallopian tube
describe the structure and histology of fallopian tube
- 10cm long
- lined by simple columnar epi (secretory and ciliated)
- smooth muscle layer
fimbriae:
- finger like extensions
- create current over ovary to waft oocyte into fallopian tube
infundibulum:
- highly folded mucosa
- thin Muscularis
ampulla:
- highly folded mucosa
- thick Muscularis
- fertilisation takes place here
isthmus:
- mucosa has fewer folds
- thickest Muscularis
describe the three layers of the uterus
endometrium:
- simple columnar epi
- functional zone (glands)
- basilar zone (closest to myometrium not sloughed during menses)
myometrium:
- smooth muscle and vasculature
perimetrium:
- CT
outline what structures the male reproductive system consists of
- testes
- epididymis
- ductal system
- accessory glands
- penis
describe the histological structure of the testes
- enclosed in thick CT –> Tunica Albuginea
- septa from Tunica Albuginea divides organ into appx 250 pyramidal lobules
- each lobule contains 1-4 seminiferous tubules
- tubules connect via rete testis prior to efferent ducts that lead to epididymis
describe the seminiferous tubules histologically
- site of spermatogenesis
- lined by Sertoli cells (simple columnar) which support and nourish developing germ cells
tight junctions between Sertoli cells - germ cells sit in invaginations of Sertoli cell cytoplasm
- Leydig cells occur in CT around tubules, secrete testosterone
what 4 populations of germ cells are in the seminiferous tubules
- spermatogonia
- spermatocytes (1st and 2nd)
- spermatids
- spermatozoa
what is spermiogenesis
late spermatid –> spermatozoan
describe the epididymis
- site of maturation and storage of spermatozoa
- highly convoluted duct w/ pseudo stratified columnar epi and stereocilia (microvilli)
describe the Vas Deferens
- encapsulated w/ DIRCT
- columnar epi
- thick wall w/ 3 smooth muscle layers
- -> inner and outer longitudinal
- -> middle circular
- contraction of muscle moves spermatozoa from epididymis to urethra during ejaculation
give the 3 accessory glands and their function
seminal vesicles:
- prod viscous secretion containing sperm activating substances (60% of ejaculate)
prostate:
- produces thin milky fluid containing several enzymes (30% of ejaculate)
- alkaline pH to counter vaginal acidity
bulbourethral (Cowper’s)
- produce clear fluid prior to ejaculation to lubricate distal urethra and neutralise it
describe the penis histologically
- erectile tissues composed of DIRCT and smooth muscle
- comprised of 3 vascular cylinders
- -> 2x corpus cavernosa
- -> 1x corpus spongiosum
- corpus cavernosa sit dorsally separated by median septum, surrounded by Tunica Albuginea
- corpus spongiosum ventral and contains urethra
