Basic Physiology - Females

Question 1

What are the steps of a developing ovarian follicle in the ovary? [7]

Answer 1

Stroma

• > Primordial Follicle
• > Growing Follicle
• > Vesicular Follicle
• > Mature Grafiaan Follicle containing Antrum (antrum surrounds oocyte)
• > Oocyte (Egg) is then released aka ovulation
• > Follicle becomes a Corpus Luteum (Young then mature)
• > Corpus luteum then regresses and becomes an ovarian scar known as a Corpus Albicans

Question 2

When do primary and secondary oocytes become haploid?

Answer 2

The primary (Diploid) Oocyte undergoes mitosis and becomes meiosis at puberty, it pauses and only completes meiosis just before ovulation.

Secondary (Haploid) Oocyte is then released in ovulation. It starts its second meiotic division which only completes after the sperm has reached the 2* oocyte.

Question 3

What triggers ovulation?

Answer 3

The LH (Luteinising Hormone) Surge which occurs due to high levels of oestrogen.

Question 4

How do oestrogen affect LH and therefore ovulation? [2]

Answer 4

Low levels of oestrogen have a negative feedback effect on the hypothalamus & Ant Pit
But then around day 12-14 of the menstrual cycle the levels reach a threshold where they trigger a positive feedback –> LH surge and ovulation

Question 5

Major female reproductive hormones? [5] and state their respective sources

Answer 5

• GnRH (Hypothalamus)
• LH (Ant Pit)
• FSH (Ant Pit)
• Oestradiol (Granulosa cells)
• Progesterone (Corpus Luteum aka CL)

Question 6

What does GnRH do? [1]

Answer 6

Stimulates LH & FSH from Ant Pit

Question 7

What does LH do? [2]

Answer 7

Induces follicle maturation and ovulation

Stimulates CL function

Question 8

What does FSH do? [1]

Answer 8

Stimulates Follicle recruitment and development

Question 9

What does Oestradiol do? [4]

Answer 9

Support 2* female sex characteristics as well as reproductive organs
Negative feedback on LH & GnRH until late follicular stage –> positive feedback for LH surge
Stimulates endometrial proliferation
Negative control of FSH

Question 10

What does Progesterone do? [2]

Answer 10

Maintains secretory endometrium

-ve feedback on HPO (Hypothalamic-Pituitary-Ovarian Axis)

Question 11

How does oocyte number change over time? What is this process called

Answer 11

7 million sa foetus down to roughly 500000 by puberty

Atresia

Question 12

Effects of estrogen [7]

Answer 12

• Protein/carb/lipid metabolism
• Water/electrolyte balance
• Clotting
• Fat Distribution
• Mammary gland development
• Bone maturation and turnover
• CNS effects