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Flashcards in Menstrual Cycle Deck (20):
0

What happens in the preparation phase?

Follicles grow in the ovary
Uterus prepares for sperm transport and implantation of the conceptus
Changes occur to facilitate sexual interactions

1

What are the names of the preparatory phase?

Follicular phase in ovaries
Proliferative phase in the uterus

2

Other terms for the waiting phase?

Luteal
Secretory

3

What happens in the waiting phase?

Corpus luteum is in the ovary
Changes occur in preparation for pregnancy
Ended by shedding of part of endometrium

4

What are the gonadal steroids and the gonadotrophins?

Steroids - oestrogen and progesterone
Trophins - LH and FSH

5

Actions of the gonadotrophins?

Follicular phase
-FSH binds to granulosa cells
-LH binds to thecal cells (theca interna)

Pre-ovulation
-LH surge stimulates ovulation

Luteal phase
-LH maintains the corpus luteum

6

Which hormones does the corpus luteum secrete?

Progesterone and a bit of oestrogen

7

What is the actions of the gonadal steroids in the follicular phase?

Oestrogen stimulate Fallopian tube function
Thickening of endometrium (secretes fluid to support sperm)
Growth and motility of myometrium (muscle contraction - sperm transport)
Vaginal changes
Changes in skin, hair, metabolism, calcium metabolism

8

What is the effect of gonadal steroids in the luteal phase?

Progesterone acts on oestrogen primed cells to cause more thickening of endometrium into secretory form
Thickening of myometrium but reduced motility
Thick, acid cervical mucus
Changes in mammary tissue
Increased body temperature
Metabolic changes
Electrolyte changes

9

Why is thick, acid cervical mucus produced in the luteal phase?

Protects the uterus from sperm and bacteria - action of contraception

10

How does the brain monitor the growth of follicles?

The bigger the follicle, the more oestrogen it produces

11

Why is there high FSH at the start of the menstrual cycle?

Corpus luteum absent, follicles only partially developed
Therefore little secretion of steroids or inhibin so little inhibition at the hypothalamus or anterior pituitary

12

What does the FSH do at the start?

Binds to granulosa cells, causing follicular development to continue and the theca interna develops

13

What does the developing follicle start to secrete and what are the effects?

Granulosa cells secrete oestrogen stimulated by LH and inhibin
Inhibin inhibits FSH and no new follicles can develop
The oestrogen exerts positive feedback at the hypothalamus so LH levels rise but FSH cannot due to inhibin

14

What factors can affect when ovulation occurs?

Copulation
Stress

15

What happens after ovulation?

Corpus luteum forms spontaneously
Begins to secrete oestrogen and progesterone which maintains suppression of FSH
LH is also suppressed because positive feedback is inhibited by progesterone

16

What happens in the luteal phase?

Corpus luteum grows and secretes more steroids
After exactly 14 days it dies

17

What does the death of the corpus luteum cause?

Rapid fall in steroids levels
Stimulates menses
Relieves inhibition of FSH a
Begin again

18

What is the interval between ovulation and menses?

Always 14 days

19

If conception occurs, what happens?

Conceptus implants
Developing placenta secretes human chorionic gonadotrophin which preserves the corpus luteum
Corpus luteum secretes increasing amounts of steroids
Many physiological changes and the placenta will soon secrete more
By 12-14 weeks, corpus luteum no longer supports pregnancy