Basic Physiology - Quines

Question 1

What are the steps of a developing ovarian follicle in the Ovary?

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 Oocytes become haploid?

Answer 2

The primary (Diploid) Oocyte undergoes mitosis and begins meiosis in utero, 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 & Progesterone affect LH and therefore ovulation?

Answer 4

Low levels of oestrogen have a -ve 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 +ve feedback –> LH surge and ovulation

Question 5

Major female reproductive hormones?

Answer 5

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

Question 6

What does GnRH do?

Answer 6

Stimulates LH & FSH from Ant Pit

Question 7

What does LH do?

Answer 7

Induces follicle maturation and ovulation

Stimulates CL function

Question 8

What does FSH do?

Answer 8

Stimulates Follicle recruitment and development

Question 9

What does Oestradiol do?

Answer 9

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

Question 10

What does Progesterone do?

Answer 10

Maintains secretory endometrium

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

Question 11

How does oocyte number change over time?

Answer 11

7 million sa foetus down to roughly 500000 by puberty

Question 12

Quickly summarive the effects of Oestrogen outside of reproductive organs?

Answer 12

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