Date post: | 07-May-2015 |
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Dr. Louis Toth – Fall [email protected]
This is being Reproduced for the benefits of Student.
Our sincere thanks and warm regards to the Author of this article,
Prof. M.C.Bansal. prof Veena Acharya.
Female Reproductive Anatomy
labia majora
labia minora
glans clitoris
corpus cavernosaof clitoris
ovary
oviduct
uterus
vagina
cervix
at menopauseyoung
pituitary gland
uterus/cervix
ovaries vagina
Organs of the female reproductive system
FSHprolactin
GnRH
oxytocin
LH
progesterone
estrogens
hCG, estrogens, progesterone, etc.
oviducts
1. Oogenesis - production of oocytes
2. Steroidogenesis - hormone production
estrogens - estrone (E1), estradiol (E2), estriol (E3) - growth/maturation of sex organs - female secondary sex characteristics - literally “estrus-generating”
progesterone - prepares uterus for implantation - prepares mammary glands for lactation - literally a “promoter of gestation” (progestegen)
progesterone
estrogens
estrone
testosterone Estradiol
cholesterol
(DHEA)
estriol
progesterone
Floyd Landis (Phonak - iShares) - 2006 Tour de France winner? Photo copyright Fotoreporter Sirotti.
tunica albuginiaof ovary
“germinal” epithelium(mesothelium of peritoneum)
medulla
cortex
Hilum - vessels and nerves enter- connective tissue support
Ovary at birth Active ovary
www.udel.edu
Primordial follicle
Primary follicle
Secondary follicle
Graafian (tertiary) follicle
Corpus luteum
Corpus albicans
Atretic follicle
Primary oocyte
Secondary oocyte
Secondary oocyte
Ovum
Zygote
• 6 weeks: primordial germ cells form and migrate to the genital ridge --> induce development of the ovaries
• 6 weeks - 5 months: mitosis --> 6 million oocytes
• 5 - 7 months: meiosis --> arrested at prophase I; oocytes become surrounded by follicle cells
• primary oocytes• primordial follicles
• birth: 1 million primordial follicles remain
• birth: 1 million primordial follicles
• puberty: 400,000 primordial follicles remain
• age ~12-52: 15-20 follicles start to mature each month; typically only one makes it to ovulation 20 foll *12months*40yrs = 9600
• menopause: no viable follicles remain
• Primary oocyte remains arrested at prophase I as the follicle develops
• Just before ovulation, meiosis I is completed
• One cell gets most of the cytoplasm -> secondary oocyte
• The other cell is the first polar body
Human embryo. Arrow = polar body
primary oocyte arrested at prophase I
secondary oocyte in mature follicle - arrested at metaphase II
secondary oocyte in oviduct
zygote(proper)
ovulation
sperm entrycompletes meiosis II
completes meiosis I
first polar body
second polar body
pronuclei fuse ovum(proper)
secondary follicle
primary follicles
primordial follicle
mature follicle
corpus luteum corpus albicans
oocyte
follicle cells
oocyte
granulosa cells
• Oocyte enlarges and matures
• Follicle cells become cuboidal = granulosa cells
theca folliculi
zona pellucida
• granulosa cells divide
• oocyte secretes zona pellucida;
• oocyte and granulosa cells remain interconnected by gap junctions
• stromal cells form the theca folliculi
theca externa
theca interna
antrum
• theca folliculi theca interna: steroidogenic; secrete estrogen precursors
theca externa: contains fibroblasts & smooth muscle
• granulosa cells: convert estrogen precursors into estrogens
theca externa
theca interna
antrum
cumulus oophorus+ corona radiata
Follicles which do not reach ovulation degenerate by atresia:
• pyknotic nuclei
• granulosa cells sloughing off into the antrum
Atresia can occur at any stage of follicular development
corona radiata
zona pellucida
• oocyte + corona radiata + zona pellucida are expelled from the follicle
• increased pressure in antrum
• enzymes secreted by granulosa cells break down wall of follicle and ovary
• smooth muscle in theca externa contracts
Normally only one oocyte is ovulated each cycle. When more than one is ovulated, fraternal twins can result.
Polycystic ovary syndrome (PCOS): follicles form but ovulation does not occur
Norman, Wu, Stankiewicz MJA 2004
Ephraim McDowellFirst laparotomy (oophorectomy),
Danville, KY 1809www.pathguy.com
corpus luteum
• After ovulation, the remaining follicle cells form the corpus luteum
• former granulosa cells become granulosa lutein
• former theca interna cells become theca lutein
•granulosa lutein and theca lutein cells cooperate to secrete progesterone and estrogen
theca lutein cells
granulosa lutein cells
If implantation occurs, embryonic hCG maintains the corpus luteum, which in turn maintains the pregnancy
corpus albicans
If implantation does not occur, the absence of hCG causes the corpus luteum to deteriorate, leaving behind a corpus albicans
isthmus
ampulla
fimbriae ofinfundibulum
intramural portion
Chicken oviduct : Thomas Caceci education.vetmed.vt.edu Advanced Fertility Ctr., Chicago
Laparoscopy image
Fimbria (= “fringe”)move to cover site of ovulationsweeps oocyte into oviduct
Infundibulum (= “funnel”)first portion of tubehighly folded epitheliumthin muscularismore ciliated cells
Ampulla (= “bottle, jar”)usual site of fertilization
Isthmus ( = “bridge”)thickest muscularismore peg cells
Intramuraltraverses wall of uterus
Wheater’s 8th ed.
Ciliated cells … …beat towards uterus to propel the oocyte …are more frequent towards fimbriaePeg cells …secrete mucus …are more frequent towards uterus
Ratio of ciliated/peg cells changes and correlates with menstrual cycle
Functions: • provides environment for developing embryo• expels embryo at birth
3 Layers:• endometrium (mucosa of the uterus):
• simple columnar secretory epithelium with simple tubular glands• very well vascularized connective tissue• subdivided into 2 layers: stratum basale + stratum functionalis
• myometrium (muscularis of the uterus): • very thick muscularis organized into three indistinct layers• capable of extreme expansion during pregnancy
• some increase in the number of muscle fibers• great increase in size of existing fibers
• perimetrium (serosa of the uterus):
Functions: - prevents uterine infection - allows sperm to enter uterus
2 parts• endocervix: continuous with endometrium
- simple columnar, mucus-secreting epithelium
- plicae palmatae: crypts
• ectocervix: continuous with vaginal epithelium- stratified squamous non-keratinized
epithelium- screened for cervical cancer by PAP smears
Portio vaginalis – the portion of the cervix that extends into the vaginal canal
The border between endocervix (simple columnar) and ectocervix (stratified squamous) epithelia is located roughly at the external os, and may be more or less extroverted depending on age, parity and other factors
• UK is considering mandatory inoculation for schoolchildren •Australia has subsidized the vaccine, making it available free of charge
Functions: - transport of sperm to uterus - expulsion of newborn - protect against bacterial infections
Histology:• stratified squamous non-keratinized• no glands• thick lamina propria• thin muscularis
• stratified squamous keratinized epithelium• hairless• elastic – stretches during delivery• homologous to male scrotum
Homologousgerm cells -> oogonium, male gametesurogenital sinus -> penile urethra, vestibule of
vaginalabioscrotal folds -> labium, scrotumgenital tubercle -> penis, clitoris
Not homologousMesonephric duct -> Epididymis, vas deferens
≠Paramesonephric duct -> fimbria, oviduct