Menstrual Cycle

Question 1

The whole menstrual cycle is made up of which 2 cycles?

Answer 1

Ovarian

Uterine

Question 2

Approximately when is ovulation?

Answer 2

Day 14

Half way though cycle

Question 3

In simple terms, what are the roles of the ovarian and uterine cycles?

Answer 3

Ovarian = preparation of gametes 
Uterine = preparation of endometrium

Question 4

Why do we need a waiting phase?

Answer 4

To maintain the endometrium until a signal has been received to indicate whether or not fertilisation has occurred
Would need the endometrium to support the conceptus

Question 5

When is the follicle capable of oestrogen secretion?

Answer 5

After a small amount of development due to FSH

Must have a theca interna

Question 6

What happens in the mid-follicular phase?

Answer 6

A dominant follicle is recruited
Follicular oestrogen high - positive feedback effect starts
LH rises
Follicular inhibin rising - selective inhibition of FSH

Question 7

When does progesterone production begin?

Answer 7

When granulosa cells become responsive to LH

Question 8

When is meiosis I complete?

Answer 8

At ovulation

Question 9

What are the effects of LH?

Answer 9

Ovulation

After ovulation the follicle is luteinised to secrete oestrogen and progesterone in large quantities

Question 10

What is the luteal phase?

Answer 10

In ovarian cycle after ovulation
Corpus luteum lives for exactly 14 days unless hCG signal
Produces progesterone and oestrogen
Produces inhibin
Regresses spontaneously in absence of LH/hCG

Question 11

What part of the embryo produces hCG?

Answer 11

Syncytiotrophoblast

Question 12

Why is hCG not detected before 2 weeks after fertilisation?

Answer 12

Have to wait for syncytiotrophoblast to develop

This occurs in week 2 (the week of 2s)

Question 13

What happens to the corpus luteum in pregnancy?

Answer 13

Supported by placental hCG

Produces steroid hormones to support the pregnancy

Question 14

What are the 2 phases of the ovarian cycle?

Answer 14

Follicular phase (0-14)
Luteal phase (14-28)

Question 15

Briefly describe the follicular phase

Answer 15

Recruiting follicles and nominating a dominant

Question 16

Briefly describe the luteal phase

Answer 16

Corpus luteum producing oestrogen and progesterone to keep things going until we know the status of fertilisation

Question 17

What are the phases of the uterine cycle?

Answer 17

Menses (0-4 days)
Proliferative phase (4-14 days)
Secretory phase (14-28 days)

Question 18

Simply, what happens in the secretory phase?

Answer 18

Endometrium becomes very glandular

Question 19

How does menses occur?

Answer 19

Gonadal hormone decrease causes spasm in arteries

Causes ischaemia of endometrium leading to shedding of that tissue

Question 20

What are the actions of oestrogen in the follicular phase?

Answer 20

Fallopian tube function 
Thickening of endometrium 
Growth and motility of myometrium
Thin, alkaline cervical mucus 
Vaginal changes
Changes in skin, hair and metabolism

Question 21

What are the actions of progesterone in luteal phase?

Answer 21

Further thickening of endometrium 
Thickening of myometrium but reduction of motility 
Thick, acidic cervical mucus 
Changes in mammary tissue
Increased body temp 
Metabolic and electrolyte changes

Question 22

Why do we decreased motility of myometrium in the luteal phase?

Answer 22

Don’t want to expel the conceptus

Question 23

Why does the cervical mucus become thick and acidic in the luteal phase?

Answer 23

Limits potential for infection

Question 24

A normal cycle is between …

Answer 24

21 - 35 days

Question 25

Variations in cycle are due to …

Answer 25

Variation in follicular phase length

Luteal phase strictly controlled to 14 +/- 2 days

Question 26

Give some factors affecting the menstrual cycle

Answer 26

Pregnancy
Lactation
Emotional stress
Low body weight