Uterus, Uterine Tubes & Cervix Flashcards
Describe the changes in the uterus & Cervix
- Maternal steroids increase size of new born uterus
- Grows with height during infancy
- Myometrium dependent on estradiol
- Corpus of uterus undergoes greater increase in size than cervix
Describe how the myometrium grows
- Outer muscular myoentrium grows gradually throughout childhood
- Increases rapidly in size and configuration during puberty
- Changes in size through the cycle. Capable of vast expansion during pregnancy
What is the endometrium dependent on?
Dependent on Steroids and responds cyclically to hormones changes
Describe the growth of the endometrium?
- Very thin during childhood. Begins to thicken at puberty
- Estrogen principally causes growth in proliferative phase.
- Can be seen and measured on an ultrasound
- Good bioassay of estradiol level (7-16 mm)
- Changes in the grandular and epithelial cells through the cycle
What does progesterone mainly cause?
Differentiation in the secretory phase
Where is most of the endometrium lost?
During the menstruation phase
What happens after most of the endometrium is lost?
After menstruation
- Stromal matrix with small columnar cells with grandular extensions about 2-3mm thick glands are simple and straight
What are the two types of endometrial phases?
- Proliferative phase
- Secretory phase
What is the Endometrial Proliferative phase?
- The Proliferative phase is “The follicular phase of ovary”
- Occurs following the menses
- Stimulated by estrogen from the growing follicle
What occurs during the Endometrial Proliferative phase?
- Stromal cell division occurs on a ciliates surface
- Causes glands to expand and become torturous
- Increases Vascularity and neoangiogenesis
- Maximal cell division by days 12-14
What happens when the endometrium is >4mm?
- Induction of progesterone receptors
- Small muscular contractions of myometrium
What is the Endometrial secretory phase?
- Secretory phase is “Luteal phase of the Ovary”
- Occurs 2-3 days after ovulation
- The gradual rise in progesterone causes a reduction in cell division
What occurs in the Endometrial secretory phase?
- Glands increase in tortuosity and distend
- Causes secretions of glycoproteins and lipids to commence
- Oedema increases vascular permeability, arterioles and grow tightly
- Myometrial cells enlarge and movement is suppressed
- Bloody supply increases
Describe the regression of the corpus luteum
- The Corpus Luteum is stimulated by LH from the pituitary gland during the luteal phase
- The fertilised Oocyte becomes a blastocyst and produces human chorionic gonadotrophin (hCG)
- This acts like LH ie On LH receptor & rescues the ‘CL’
In the absence of this, falling levels of steroid from the CL results in menstruation
What are the processes that occur during menstruation? (PART 1)
Prostaglandin release causes constriction of spiral arterioles
- Hypoxia causes Necrosis
- Vessels then dilate and bleeding ensues
- Proteolytic enzymes are released from the dying tissue
What are the processes that occur during menstruation? (PART 2)
- Outer layer of endometrium shed, 50% lost in 24hrs, up to 80ml is considered normal.
- Bleeding normally lasts 4+ days.
- Basal layer remains and is then covered by extension of glandular epithelium
- Estrogen from follicle in next follicular phase starts cycle off again
What are the 3 different cross sections of the uterine tube?
- Intramural
- Isthmus
- Ampullary
What are the different type of cells in the mucosa of the uterine tubes?
- Secretory
- Columnar ciliates epithelial
- Non ciliated Peg
Describe the muscularis in the uterine tube
- Inner circular & outer
- Longitudinal layers
- Blood vessels & lymphatics
What happens to the epithelial cells during changes in cells lining the uterine tubes?
Epithelial cells express high numbers of estrogen receptors & undergo differentiation in response to estradiol increase in height mid-cycle
What happens to the Oocytes during changes in cells lining the uterine tubes?
- Oocyte can only pass down the tube during mid-cycle
- Cilia beat and secretory cells are active along with muscle layer contractions, all in response to estrogen
What happens to the estrogen receptors during changes in cells lining the uterine tubes?
- After a few days of exposure to progesterone, the estrogen receptors become suppressed
- Estrogen effects are overcome causing decrease in height mid luteal onwards
Fertilisation & early embryo development
How long does the Egg remain in the tube for?
Approximately 5 days
Where does fertilisation occur?
Occurs In the ampulla
What could damage to the tube cause?
- Damage to the lining of the tube by infection, endometriosis, surgery or adhesions
- May cause blockage or damage to ciliated epithelial resulting in
- Pain, Infertility, ectopic pregnancy
Briefly describe the cervix
Muscular structure capable of great expansion
Describe the structure of the cervix
The endocervical mucosa is about 3 mm thick
- Lined with a single layer of columnar mucous cells containing numerous tubular mucous glands which empty viscous alkaline mucus into the lumen
What is the purpose of the viscous alkaline mucus?
- Protective barrier to infection
- However it has to allow passage of motile sperm
Describe the ectocervix structure of the cervix
The ecto-cervix is covered with nonkeratinized stratified squamous epithelium, resembling the squamous epithelium lining the vagina
What does Estrogen in the follicular phase cause?
Change in vascularity of cervix and oedema
What does mid cycle estrogen levels cause?
- They cause a change in mucous to become less viscous
- Change in mucous composition
- Mucus contains glycoproteins
- These glycoproteins become aligned and form microscopic channels
- Sperm swing up the channels
What does progesterone in the luteal phase cause?
- Reduced secretion and viscous mucous (reduced water content)
- Glycoproteins now form mesh like structure: acts as barrier to sperm and microorganisms
- One mechanism of action of oral contraceptives
Describe the structure of the vagina
- Thick walled tube approximately 10 cm
- Lined by specialised ‘squamous epithelial’ cells
- Warm damp environment containing glycoproteins
- Susceptible to infection
How is Vaginal infection prevented?
- Layers of epithelial cells shed constantly and ‘flow’ downwards with the secretions.
-Secretions are from cervix and transudation from vaginal epithelium - Secretions change with cycle and are generally acidic providing anti-microbial protection
Where are Bartholins glands located?
Bartholins glands located slightly posterior and to the left and right of the opening of the vagina
What do Bartholin glands do?
- Secrete mucus to lubricate the vagina
- And are homologous to bulbourethral glands in males.
