Histology - Female Genital Tract and Pregnancy Flashcards
Example of autocrine signaling in female gen tract
Activin from granulosa cells up regulates FSH receptors on their surface
Example of paracrine signaling in female gen tract
Inhibin from granulosa cells act on theca interna (assists LH in androstenedione synthesis)
What is cortex of ovary lined by
Simple cuboidal/ squamous epithelium (tunica albuginea)
Epithelium of endocervical canal
Mucus secreting simple columnar epithelium
Epithelium of ectocervix
Stratified squamous epithelium
Development of transformation zone
Estradiol causes eversion of endocervical canal and columnar epi exposed to acidic pH. Squamous metaplasia (epidermalisation)
Risks associated with transformation zone
- Infection (early puberty)
- Nabothian cyst
- Dysplasia
- Carcinoma
Epithelium of vagina
Stratified squamous epithelium (produces glycogen under influence of estriol)
Role of glycogen in vaginal
Lactobacilli convert glycogen to lactic acid creating an acidic pH
Vaginal lubricated by
(Vaginal lacks glands)
Uterine glands
Endocervical glands
Glands of Bartholin (vestibules)
Epithelium of uterine tubes
Simple columnar epi.
Ciliated - larger in follicular phase, estrogen increases motility.
Secretory (peg) cells - increase secretion w estrogen
Fx of secretions in uterine tubes
Capacitation of sperm
Nutrients for ovum, sperm, morula
Features of atretic follicles
Delamination of granulosa cells (pyknotic nuclei, apoptotic bodies)
Collapse
Fibrous body -> corpus albicans
Five stages of follicular development
Primordial follicle Primary follicle - unilayered Primary follicle - multilayered Secondary follicle Graafian follicle
Three regions of granulosa cells in Graafian follicle
Mural granulosa cells
Cumulus oophorous
Corona radiata
When is dominant follicle determined
Day 7
How is steroid produced in follicle
Granulosa cells lack enzymes to generate steroid. Therefore, theca interna cells produce androstenedione which is taken up by the GCs and converted to estradiol by aromatase
Role of follicle hormones in estradiol synthesis
Activin - released by GCs up regulates FSH receptors on GCs (autocrine)
FSH - increases aromatase activity in GCs. Increases the expression of inhibin in GCs
Inhibin - acts on theca interna (paracrine) assisting LH in androstenedione synthesis
What does LH surge do
- Halts estrogen production
- Initiates 2nd meiotic division (block oocyte maturation-inhibitory substance of GCs)
- Increase local prostaglandin production (vascular changes = follicle swelling, proteolytic enzyme action on ovary stroma)
- Differentiate follicular cells to form granulosa lutein cells (take up cholesterol)
Formation of corpus luteum
BM breaks down. Invasion of blood vessels into theca lutein. LH causes cholesterol uptake. Theca lutein produces progesterone and androstenedione.
FSH still needed for aromatase
Changes seen in uterine cycle from proliferators phase -> secretory phase
Endometrium thin -> thick
Glands straight/tortuous -> saw toothed, many secretions
Cells low/tall -> basal/apical glycogen
Stroma Mitotic figures -> large decidual-like/ oedema and lymphocytes
What happens in ischemic phase of uterine cycle
Release of prostaglandins = spiral artery spasm. Hypoxia = stroma flooded w blood. Functional layer shed. Basal layer remains intact (straight arteries)
Eversion of endocervical canal forms
Ectropion
Process of female sexual arousal
Parasympathetic activation - engorgements of clitoris.
Increased vaginal excretions.
Engorged blood vessels.
Orgasm - peristaltic contractions of vaginal/uterus.
Pudendal nerve = rhythmic contraction (bulbosongiosus/ ischiocavernosus)
Effect of contraceptive pill
- HP axis - inhibits synthesis/secretion of FSH. Therefore, no follicle maturation/ LH surge/ ovulation.
- Cervix - cubical mucus thicker, more hostile. Prevents sperm entry.
- Endometrium - lining thins, alters tubes (ovum can’t travel easily)
Mechanism of morning after pill
Synthetic progesterone prevents implantation
Mechanism of estrogen-progesterone-glucocorticoid receptor antagonist
Non supportive endometrium
Mechanism of prostaglandin E2 contraceptive
Uterine contractions
Role of estrogens in the female
Many genital tract changes
Bone deposition
Cardiac protection (cholesterol metabolism, antioxidant, vasodilation, regulates arterial muscle proliferation after injury)
Modulates E and NE actions
Fx of syncytiotrophoblasts
- Release proteases - erode maternal tissue
- Secrete hCG - maintain corpus luteum
- No MHC
- Line inter villus space
- Microvilli brush border increases SA for exchange
Fx of cytotrophoblasts
- Syncytiotrophoblast precursor
- Secretes FAS ligand - kills T cells
- Anchors villus stem to decidua by secreting fibrinogen substance
- Invasion of spiral arteries to form maternal sinusoids and regulate blood flow (poor invasion = abortion, eclampsia, growth retardation)
Immune protection mechanisms in placenta
Decidua - prostaglandins inhibit NK cells. Infiltration leukocytes secrete IL 2
Inter villus space - IgGs
Chorionic villi - syncytiotrophoblasts have no MHC. Cytotrophoblasts secrete FAS ligand
Hofbauer cells in early pregnancy = phagocytosis
Describe process of blastocyst attachment
- Blastocyst hatches from zona pellucida
- Trophoectoderm binds uterine surface
- Primary decidual zone formed (cells proliferate, ECM proteins laid down, various proteins released)
- Vasculature becomes permeable at implantation site.
Describe process of blastocyst implantation
- Trophoectoderm invades uterine luminal cells which undergo apoptosis.
- Reduced desmosomes helps embryo penetration.
- Secondary decidual zone replaces primary zone.
What makes secondary villus different to primary
Extraembryonic mesodermal core
Role of decidua cells
Luteal phase - secrete decidual prolactin -> GF for corpus luteum
After implantation - modulate trophoblast implantation, provide nutrients for embryo, prostaglandins inhibit NKs, secrete relaxin, secretes IGF binding protein preventing endometrial gland proliferation, prostaglandins regulate blood flow.
How is estrogen produced in pregnancy
Fetoplacental unit.
Cholesterol -> pregnenalone -> progesterone in placenta
Progesterone -> DHEA in fetal adrenals
DHEA -> estrogen in placenta
What is the placental luteal shift
Chorionic gonadotropin used instead of LH to maintain the corpus luteum
Why may glucose and insulin be high in preg woman
Human chorionic somatomammotropin (placental lactogen) increases liver resistance to insulin. [ structure similar to GH and prolactin ]
Role of human chorionic somatomammotropin
Fetal growth
Mammary gland development
Pregnancy’s effect on maternal physiology
Alveolar respiration (>progesterone) Tidal volume Maternal blood volume Nutrient requirements GFR Uterus size Mammary gland growth + development
Role of cortisol in parturition
Fetal lungs exposed to more pulmonary surfactant = maturation
Surfactant protein in amniotic fluid = macrophages causing increase prostaglandin production.
Role of estrogen in triggering parturition
Increase number of gap junctions = synsytium
Increase oxytocin receptors in myometrium = increased responsiveness to low levels of oxy
Increase prostaglandin production = cervical softening
Describe process responsible for progression of parturition
Oxytocin causes uterus to contract. Fetus pushed against cervix -> ferguson reflex causes more oxytocin release increasing prostaglandin production and causing more contraction (positive feedback cycle)
Structure where all mammary glands meet
Lactiferous sinus
What inhibits lactation
High levels of estrogen
Dopamine
Constituents of colostrum
Proteins (merocrine)
Lipids (apocrine)
Lactose -> draw water into milk by creating osmotic gradient
What initiates lactation
Increase cortisol -> milk synthesis enzymes induced
Rapid fall in estrogen overrides dopamine’s inhibitory effect
How is prolactin secretion controlled
Dopamine inhibits prolactin. Suckling inhibits dopamine release allowing increase in prolactin stimulating galactopoeisis. Suckling also stimulates oxytocin release causing contraction of myoepithelial cells.
NB prolactin inhibits GnRH therefore no menses
Other functions of oxytocin
Pair bonding with sexual partner
Maternal behavior
Cells seen on Pap smear (normal)
Large squamous epithelial cells with pyknotic nuclei = surface epithelium. Can be acidopholic (Pre) or basophilic (post) ovulation.
Columnar cells of endocervix indicates that the TZ and squamocolumnar junction cells are present
