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
Q

How long is the ovarian cycle?

A

24-32 days

2
Q

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

A

Follicular stage (10-14 days)

3
Q

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

A

Luteal phase (12-15 days)

4
Q

What hormone dominates pre-ovulation?

A

oestrogen

5
Q

What hormone dominates post-ovulation?

A

Progesterone

6
Q

What is the fate of preantral follices?

A

Majority undergo <b>atresia</b><br></br>Some spontaneously form antral follicles<br></br><br></br><b>No antral follicles can form in luteal phase due to effect of progesterone</b>

7
Q

What are the effects of oestrogen in follicular stage?

A

1) ↑ LH → follicular growth and maturation to pre-ovulatory follicle<br></br><br></br>2) Arterial growth<br></br><br></br>3) <b>Thickening of endometrium</b> towards ovulation<br></br><br></br>4) ↑ mucus secretion

8
Q

During what phase does the endometrium develop progesterone receptors?

A

Follicular phase (even though no progesterone in this phase)

9
Q

What occurs in luteal phase?

A

1) Arteries taken on spiral form<br></br><br></br>2) ↑ Progesterone → ↓ mucus secretion and prevents sperm penetration

10
Q

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

A

Follicular = <b>Spinnbarkeit</b> (towards ovulation)<br></br><br></br>Luteal = <b>Ferning</b> (uniform, organised structure)

11
Q

What are the endocrine cells of the pituitary gland?

A

<b>1) Gonadotrophs</b> → LH + FSH<br></br><b>2) Somatotrophs</b> → GH<br></br><b>3) Lactotrophs</b> → Prolactin<br></br><b>4) Thryotrophs</b> → TSH<br></br><b>5) Corticotrophs</b> → ACTH

12
Q

What nuclei are involved with GnRH release?

A

1) Medial pre-optic nucleus<br></br>2) Arcuate nucleus

13
Q

What feedback loops exist in males?

A

<b>Only negative feedback</b><br></br><br></br>Androgens → ↓ FSH + LH secretion by negatively inhibiting Hypothalamus and ant. pituitary<br></br><br></br>Inhibin → ↓ FSH secretion by negatively inhibiting the ant. pituitary ONLY

14
Q

“What is the ““pelvic clock”””

A

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

15
Q

What alterations are seen in LH secretion around puberty?

A

<b>Pre-puberty</b><br></br>- Low LH secretion<br></br><br></br><b>Early-mid puberty</b><br></br>- Nocturnal augmentation of LH secretion<br></br><br></br><b>Adulthood</b><br></br>- Establishment of high basal levels of LH secretion with no diurnal rhythm

16
Q

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

A

<b>GnRH pulses</b><br></br><br></br>Exogenous GnRH pulses → initiate puberty

17
Q

What weight does puberty occur at for girls and boys?

A

47kg for girls<br></br><br></br>55kg for boys<br></br><br></br>This may be due to <b>leptin</b>