5 - Repro - Control of Reproductive Processes Flashcards Preview

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Flashcards in 5 - Repro - Control of Reproductive Processes Deck (43):
1

From where is GnRH secreted?

Hypothalamus

2

How is GnRH transported to the anterior pituitary?

Hypophyseal portal system

3

Define portal system:

Vascular arrangement where blood from a capillary bed is transported to another capillary bed, via connecting veins

4

What type of cells in the anterior pituitary does GnRH act on?

Gonadotropes

5

How do the gonadotropes respond to GnRH?

Secrete FSH + LH

6

Why does oestrogen levels increase towards ovulation?

As the follicle grows, more oestrogens are secreted in response to a given gonadotropic stimulation

7

Why does progesterone and oestrogens increase after ovulation?

As the corpus luteum grows, more progesterone and oestrogens are secreted in response to a given concentration of LH

8

Leydig cells in the testes bind LH. What is the effect of this?

LH stimulates Testosterone production from Leydig cells

9

How does FSH affect Sertoli cells?

Maintains them and makes them responsive to Testosterone

10

Approx. how much testosterone is secreted by Leydig cells per day?

~ 4-10 mg/day

11

Which hormones produced by the gonads REDUCE GnRH secretion?

- Testosterone
- Oestrogen (at moderate concentrations)
- Inhibin

12

How does Oestrogen (at moderate concentrations) affect GnRH secretion?

Reduces GnRH secretions from the hypothalamus
- Reduces the amount of GnRH released per pulse

13

Why can the LH surge only occur at low concentrations of progesterone?

Progesterone inhibits oestrogen from having a positive feedback affect on the hypothalamus. This positive feedback causes a GnRH surge, which results in the LH surge from the anterior pituitary.

14

Which cells secrete inhibin?

- Females = granulosa cells
- Males = Sertoli cells (when spermatogenesis occurs too rapidly)

15

What is meant by a 'determinative' effect of testosterone?

An effect which is only partly reversible, if at all (non dependent on continuous production of testosterone)
- most secondary sex characteristics are 'determinative' effects, ie deepening of voice

16

What is meant by a 'regulatory' effect of testosterone?

An effect which is reversible, and dependent of continuous production of testosterone.
- ie maintenance of internal genitalia, aggression and sexual activity

17

What are the 2 phases of the ovarian cycle?

- Follicular phase
- Luteal phase

18

High concentrations of oestrogen cause a GnRH surge, resulting in an LH surge. Why doesn't FSH concentrations also increase?

Granulosa cells secrete inhibin, which suppresses FSH release

19

On which day of the menstrual cycle does the concentration of LH peak?

Day 13

20

On which day of the menstrual cycle does the concentration of progesterone peak?

Day 21

21

What are the 3 stages of the endometrial cycle?

- Menses
- Proliferative phase
- Secretory phase

22

Which main hormonal change causes menses to occur?

Sudden drop in progesterone (+ oestrogen)

23

Which main hormonal change causes the proliferative phase of the endometrial cycle?

Increasing concentration of oestrogen

24

Which main hormonal change causes the secretory phase of the endometrial cycle?

Increasing concentration of progesterone

25

Which hormone stimulates endometrial thickening and secretion of cervical mucus in the follicular stage?

Oestrogen

26

Which hormone stimulates the development of the spiral arteries and increase in basal body temperature in the luteal phase?

Progesterone (on oestrogen primed cells)

27

What is the length of a normal menstrual cycle?

~ 21 - 35 days

28

Which phase of the ovarian cycle is always 14 days, regardless of length of menstrual cycle?

Luteal phase

29

What is the relationship between FSH and inhibin?

Negative feedback mechanism:
When concentrations of FSH increase, this stimulates granulosa cells to secrete inhibin, which has a negative feedback effect on the hypothalamus, causing decreased FSH secretion.

30

Name the part of the fallopian tubes which capture the ovum released from the ovaries:

Fimbraie

31

What types of cells make up the epithelium of the fallopian tubes?

- Ciliated columnar cells
- Peg cells (secrete mucous)

32

Which part of the female genital tract has a convoluted lumen?

Fallopian tubes

33

Name the innermost layer of the uterine wall:

Endometrium

34

Name the 2 layers of the endometrium:

- Stratum basalis
- Stratum functionalis

35

Which layer of the uterine wall is shed during menses?

Stratum functionalis of the endometrium

36

Describe the myometrium:

- Middle layer of the uterine wall
- 4 layers of ill-defined smooth muscle

37

Describe the arteries which supply the endometrium:

- Stratum basalis = supplied by straight arteries
- Stratum functionalis = supplied by coiled arteries

38

What is the arterial supply to the uterus?

Uterine arteries (from internal iliac arteries)

39

Describe the epithelium of the cervix:

Simple columnar
- Except @ External Os: Non-keratinised simple squamous

40

Describe the epithelium of the vagina:

Non-keratinised simple squamous

41

What types of muscle make up the muscular wall of the vagina?

- Smooth
- Skeletal

42

Why do some women experience tender breasts before their menses?

Increasing concentration of oestrogen causes duct proliferation, which can cause tenderness

43

Which hormones cause breast development at puberty?

Oestrogens