Uterus and uterine tubes Flashcards
what is the muscular body of the uterus called?
the myometrium
effect of maternal steroids?
increase the size of new-born uterus
oestrogen causes an increase in?
endometrium and myometrium size
what is the perimetrium?
on the outside
what originate from the myometrium layer?
uterine fibroids
what is the structure of the myometrium?
Inner layer - circular fibres
Middle layer - spiral fibres
Outer layer - longitudinal fibres
when does the outer muscular myometrium grow?
grows gradually throughout childhood
- increases rapidly in size and configuration during puberty
- changes in size through the cycle
what is the myometrium capable of?
vast expansion during pregnancy
what is renewed every month?
the endometrium
- most of it is lost in menstruation
- it responds to oestrogen and progesterone
what is the endometrium like in childhood?
very thin in childhood, and begins to thicken at puberty
what is left of the endometrium after menstruation
stromal matrix
(smallest the endometrium can get)
-small columnar cells with glandular extensions 2-3mm thick
what grows from the stromal matrix in response to oestrogen in the follicular phase?
endometrial layer
the CL produces progesterone to….
……maintain endometrium thickness
after ovulation what happens to the arteries
the arteries become more spiralled
-large SA which delivers a lot of blood and oxygen to the endometrium
no pregnancy means what?
CL dies, progesterone levels fall and the endometrium sheds
how is the endometrium made ready for embryo implantation?
-glands proliferate
-adhesion molecules and mucus secreted
this makes the surface receptive and sticky, ready for embryo implantation
endometrial proliferative phase
- stimulated by oestrogen production from dominant follicle
- stromal cell division
- glands expand, become tortuous
- increased vascularity, neoangiogenesis
in the proliferative phase, what happens when the endometrium >4mm?
- progesterone receptors start to get expressed on the endometrium, ready for the second half of the cycle
- small muscular contractions of the myometrium
endometrial secretory phase
- 2-3 days after ovulation
- gradual rise in progesterone causes a reduction in cell division
- increase in tortuosity of glands
- secretion of glycoproteins and lipids
- arterioles contract and grow tightly wound
- myometrial cells enlarge and movement is suppressed
- blood supply increases, makes endometrium very receptive
regression of the corpus luteum
- CL stimulated by LH from pit in luteal phase
- no pregnancy, no beta-HCG
- CL dies, no progesterone production
- endometrium sheds, menstruation
how is the CL saved?
-fertilised oocyte becomes a blastocyst and produces human chorionic gonadotrophin (beta hCG) which acts like LH ie on LH receptor, and ‘rescues’ the CL
what are pregnancy tests based on?
beta-HCG levels
what happens in menstruation?
- endometrium releases prostaglandins, which constrict the spinal arterioles
- hypoxia causes necrosis
- vessels dilate, bleeding occurs
- proteolytic enzymes released from dying tissue, further tissue degradation
- basal layer remains, covered by extension of glandular epithelium
how much of the endometrium is lost in he first 24 hrs of menstruation?
50%
where does the embryo spend the first 5-6 days and how does it move?
the uterine tube
-moves along tube via peristalsis and cilia
3 cell types in the uterine tube?
ciliated
non ciliated
secretory
when is the only time the oocyte can move along the uterine tube and why?
mid cycle, in the ovulation period
- oestrogen causes cilia to waft
- activation of secretory cells
- muscle layer contractions
what happens in uterine tube before ovulation?
epithelial cells express estrogen receptors and differentiate in response to estradiol
-increase in height mid-cycle
what happens in uterine tube after ovulation?
a few days of exposure to progesterone means the estrogen receptors are supressed
-estrogen effects are overcome causing decrease in epithelial cell height mid-luteal onward
where does fertilisation occur?
the ampulla
damage to uterine tube lining can cause?
pain
infertility
ectopic pregnancy - embryo doesn’t leave the tube
name an infection that can block the uterine tube?
chlamydia
what is tubal patency?
when a women’s fallopian tubes are not blocked
what can tubal potency be demonstrated by?
- laparoscopy and dye
- small incision made in the anterior wall, laproscope put through
- a light on the end, gives a view inside the abdomen
- air is pumped in so you can see
- uterine cannula passed through the cervix, blue dye is injected into the uterus
- expect the uterus to fill up with dye, dye will travel down the uterine tubes, emerging at the fimbrial end near the opening of the uterine tubes - Hystero Salpingo-contrast Sonography
- less invasive
- put cannula through cervix, inject opaque dye that reflects ultrasound
- ultrasound probe put on the abdomen, monitor progress of dye without entering the abdomen
why would laparoscopy and dye be used?
in cases of endometriosis - visualise
what is endometriosis?
when a cell in the endometrium escapes from the uterus and gets into the pelvis or somewhere else, and implants
-still responds to oestrogen and progesterone the same way they would if they were in the uterus (proliferate, differentiate, then shed)
what is the cervix?
a muscular structure capable of great expansion
endocervical mucosa?
mucosal lining of the cervix
3mm thick, lined with a single layer of columnar mucous cells which contains tubular mucous glands which empty viscous alkaline mucus into the lumen
-protective barrier to infection
-however has to allow passage of motile sperm
what is the cervical mucus like?
-very viscous and stiff, blocks the cervix and prevents bacteria from entering
-also impenetrable to sperm
BUT during ovulation cervical mucus becomes less viscous, sperm can enter
how does oestrogen affect cervical mucus?
- early phase of the cycle glycoproteins form a mesh barrier that sperm can’t get through
- becomes less viscous
- change in mucous composition
- glycoproteins align, form microscopic channels which sperm swim up
what does progesterone in the luteal phase cause?
- viscous mucous (reduced water content)
- Glycoproteins form mesh structure, acts as barrier
- One mechanism of action of oral contraceptives.
vagina
- thick walled tube lined with squamous epithelium cells
- warm damp environment containing glycoproteins
- susceptible to infection
bartholins glands
located slightly posterior, to the left and right of the opening of the vagina
- secrete mucus to lubricate vagina
- homologous to bulbourethral glands in males.
