Uterus, Uterine Tubes & Cervix

Question 1

Describe the changes in the uterus & Cervix

Answer 1

• 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

Question 2

Describe how the myometrium grows

Answer 2

• 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

Question 3

What is the endometrium dependent on?

Answer 3

Dependent on Steroids and responds cyclically to hormones changes

Question 4

Describe the growth of the endometrium?

Answer 4

• 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

Question 5

What does progesterone mainly cause?

Answer 5

Differentiation in the secretory phase

Question 6

Where is most of the endometrium lost?

Answer 6

During the menstruation phase

Question 7

What happens after most of the endometrium is lost?

Answer 7

After menstruation
- Stromal matrix with small columnar cells with grandular extensions about 2-3mm thick glands are simple and straight

Question 8

What are the two types of endometrial phases?

Answer 8

• Proliferative phase
• Secretory phase

Question 9

What is the Endometrial Proliferative phase?

Answer 9

• The Proliferative phase is “The follicular phase of ovary”
• Occurs following the menses
• Stimulated by estrogen from the growing follicle

Question 10

What occurs during the Endometrial Proliferative phase?

Answer 10

• 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

Question 11

What happens when the endometrium is >4mm?

Answer 11

• Induction of progesterone receptors
• Small muscular contractions of myometrium

Question 12

What is the Endometrial secretory phase?

Answer 12

• 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

Question 13

What occurs in the Endometrial secretory phase?

Answer 13

• 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

Question 14

Describe the regression of the corpus luteum

Answer 14

• 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

Question 15

What are the processes that occur during menstruation? (PART 1)

Answer 15

Prostaglandin release causes constriction of spiral arterioles
- Hypoxia causes Necrosis
- Vessels then dilate and bleeding ensues
- Proteolytic enzymes are released from the dying tissue

Question 16

What are the processes that occur during menstruation? (PART 2)

Answer 16

• 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

Question 17

What are the 3 different cross sections of the uterine tube?

Answer 17

• Intramural
• Isthmus
• Ampullary

Question 18

What are the different type of cells in the mucosa of the uterine tubes?

Answer 18

• Secretory
• Columnar ciliates epithelial
• Non ciliated Peg

Question 19

Describe the muscularis in the uterine tube

Answer 19

• Inner circular & outer
• Longitudinal layers
• Blood vessels & lymphatics

Question 20

What happens to the epithelial cells during changes in cells lining the uterine tubes?

Answer 20

Epithelial cells express high numbers of estrogen receptors & undergo differentiation in response to estradiol increase in height mid-cycle

Question 21

What happens to the Oocytes during changes in cells lining the uterine tubes?

Answer 21

• 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

Question 22

What happens to the estrogen receptors during changes in cells lining the uterine tubes?

Answer 22

• After a few days of exposure to progesterone, the estrogen receptors become suppressed
• Estrogen effects are overcome causing decrease in height mid luteal onwards

Question 23

Fertilisation & early embryo development
How long does the Egg remain in the tube for?

Answer 23

Approximately 5 days

Question 24

Where does fertilisation occur?

Answer 24

Occurs In the ampulla

Question 25

What could damage to the tube cause?

Answer 25

- 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

Question 26

Briefly describe the cervix

Answer 26

Muscular structure capable of great expansion

Question 27

Describe the structure of the cervix

Answer 27

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

Question 28

What is the purpose of the viscous alkaline mucus?

Answer 28

- Protective barrier to infection - However it has to allow passage of motile sperm

Question 29

Describe the ectocervix structure of the cervix

Answer 29

The ecto-cervix is covered with nonkeratinized stratified squamous epithelium, resembling the squamous epithelium lining the vagina

Question 30

What does Estrogen in the follicular phase cause?

Answer 30

Change in vascularity of cervix and oedema

Question 31

What does mid cycle estrogen levels cause?

Answer 31

- 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

Question 32

What does progesterone in the luteal phase cause?

Answer 32

- 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

Question 33

Describe the structure of the vagina

Answer 33

- Thick walled tube approximately 10 cm - Lined by specialised ‘squamous epithelial’ cells - Warm damp environment containing glycoproteins - Susceptible to infection

Question 34

How is Vaginal infection prevented?

Answer 34

- 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

Question 35

Where are Bartholins glands located?

Answer 35

Bartholins glands located slightly posterior and to the left and right of the opening of the vagina

Question 36

What do Bartholin glands do?

Answer 36

- Secrete mucus to lubricate the vagina - And are homologous to bulbourethral glands in males.