6.0 The Ovarian Cycle Flashcards Preview

MedST IB: Human Reproduction (HR) > 6.0 The Ovarian Cycle > Flashcards

Flashcards in 6.0 The Ovarian Cycle Deck (17)
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1

How long is the ovarian cycle?

24-32 days

2

What is the name of the period of the ovarian cycle before ovulation? How long is it?

Follicular stage (10-14 days)

3

What is the name of the period of the ovarian cycle after ovulation? How long is it?

Luteal phase (12-15 days)

4

What hormone dominates pre-ovulation?

oestrogen

5

What hormone dominates post-ovulation?

Progesterone

6

What is the fate of preantral follices?

Majority undergo atresia
Some spontaneously form antral follicles

No antral follicles can form in luteal phase due to effect of progesterone

7

What are the effects of oestrogen in follicular stage?

1) ↑ LH → follicular growth and maturation to pre-ovulatory follicle

2) Arterial growth

3) Thickening of endometrium towards ovulation

4) ↑ mucus secretion

8

During what phase does the endometrium develop progesterone receptors?

Follicular phase (even though no progesterone in this phase)

9

What occurs in luteal phase?

1) Arteries taken on spiral form

2) ↑ Progesterone → ↓ mucus secretion and prevents sperm penetration

10

What is the property of mucus in follicular and luteal phase?

Follicular = Spinnbarkeit (towards ovulation)

Luteal = Ferning (uniform, organised structure)

11

What are the endocrine cells of the pituitary gland?

1) Gonadotrophs → LH + FSH
2) Somatotrophs → GH
3) Lactotrophs → Prolactin
4) Thryotrophs → TSH
5) Corticotrophs → ACTH

12

What nuclei are involved with GnRH release?

1) Medial pre-optic nucleus
2) Arcuate nucleus

13

What feedback loops exist in males?

Only negative feedback

Androgens → ↓ FSH + LH secretion by negatively inhibiting Hypothalamus and ant. pituitary

Inhibin → ↓ FSH secretion by negatively inhibiting the ant. pituitary ONLY

14

"What is the ""pelvic clock"""

A term used to describe the relationship of follicular dynamics and the timing of the menstrual cycle

15

What alterations are seen in LH secretion around puberty?

Pre-puberty
- Low LH secretion

Early-mid puberty
- Nocturnal augmentation of LH secretion

Adulthood
- Establishment of high basal levels of LH secretion with no diurnal rhythm

16

What precedes LH, FSH and sex steroid increases in puberty?

GnRH pulses

Exogenous GnRH pulses → initiate puberty

17

What weight does puberty occur at for girls and boys?

47kg for girls

55kg for boys

This may be due to leptin