Uterus, Uterine Tubes and Cervix

Question 1

Myometrium:
What is it dependent on?

What are its 3 muscle layers?

Endometrium:
How is it clinically significant?

Answer 1

• Oestrogen
• Inner CIRCULAR fibres, Middle SPIRAL fibres, Outer LONGITUDINAL fibres

• Dependant on steroids and responds to hormonal changes, therefore can be used as an estimation of Oestrogen levels on a USS

Question 2

ENDOMETRIAL PHASES:
Proliferative phase:
What stimulates it?

Describe its structure

What happens when the endometrium becomes >4mm?

Secretory phase:
What stimulates it?

How does the endometrium structure change?

How does the myometrium change?

Regression of CL:
When does this occur?

What does it lead to? How?

Menstruation:
What occurs here?

Answer 2

• Oestrogen (from Dominant follicle)
• Stromal ciliated cell division, Tortuous and expanded glands, Increased vascularity, Neonangiogenisis
• Induction of progesterone receptors and small contractions of the myometrium

• Progesterone (from Corpus Luteum)
• Increased tortuosity of glands, Distension, Oedema and increased vascular permeability, Contraction and winding of arterioles
• Enlargement of myometrial cells, Increased blood supply, Reduced tone

• Occurs when no zygote implantation occurs - (no hCG to support it)
• Drop in Progesterone = Menstruation (no support of the endometrium)

• • Constriction of Spiral arterioles due to PROSTAGLANDIN = Ischaemia and Necrosis
  • Vessels then dilate = Bleeding
  • Proteolytic enzymes breakdown necrotic tissue

Question 3

UTERINE TUBE:
What are its 2 muscle layers?

What cell types does the Mucosal layer have?

Why can the oocyte only pass down the tube Mid-cycle?

Where along the tube does fertilisation take place?

What can cause damage to it? What can it lead to?

How can Tubal Patency be checked?

Answer 3

• Inner CIRCULAR and Outer LONGITUDINAL muscular layers
• Secretory, Columnar ciliated epithelial, Non-ciliated Peg cells
• Cilia, Secretory cell, and Muscular contractions are all in response to Oestrogen
• Ampulla
• Infection, Endometriosis, Surgery, Adhesions = Pain, Infertility, Ectopic pregnancy
• • Invasive - Laparoscopy and dye
  • Non-invasive - USS and dye (HyCoSy)

Question 4

CERVIX:
What is the function of its mucous glands?

How does it change during the Follicular phase?

How does Mid-cycle affect its mucous? What does this allow for?

How does it change during the Luteal phase? How does it relate to Contraceptive pills?

Answer 4

• Protective barrier to infection and allows sperm to pass through
• Increased vascularity and Oedema
• Mid-cycle Oestrogen levels cause mucous to become less viscous
  o Change in mucous composition - Glycoproteins, which form channels for sperm to swim through
• Reduced secretion and viscous mucous
  o Glycoproteins now act as a barrier to sperm and microbes
  o One of the ways Progesterone-based Oral Contraceptives work

Question 5

VAGINA:
Describe its structure

What is it susceptible to?

How is it protected against this susceptibility?

Answer 5

• Thick-walled, 10cm long tube lined with specialised Squamous epithelium
• Infection
• • Layers of epithelial cells shed constantly and “flow” downwards with secretions
  • Cervical and Vaginal secretions
  • Acidic, Anti-microbial secretions