Menstrual Cycle

Question 1

What are the basics of the menstrual cycle?

Answer 1

Preparation

• of gamete
• of endometrium

Ovulation

Waiting

Question 2

What controls the menstrual cycle?

Answer 2

Gonadotrophins - act on the ovary

Ovarian steroids - act on tissues of reproductive tract

Question 3

What are the main gonadotrophins?

Answer 3

LH

FSH

Question 4

What are the effects of FSH?

Answer 4

Stimulates early development of the follicles

Binds to granulosa cells - supports oocytes

Question 5

What are the effects of LH?

Answer 5

Responsible for LH surge

Maintains corpus luteum

Question 6

What are the 2 main cycles of the menstrual cycles?

Answer 6

Ovarian cycle

Uterine cycle

Question 7

What are the 2 stages of the ovarian cycle?

Answer 7

Follicular phase

Luteal phase

Question 8

When does the follicular phase take place?

Answer 8

Before ovulation

Question 9

What hormone controls the follicular phase?

Answer 9

FSH

Question 10

What happens in the follicular phase?

Answer 10

FSH increases
Early development of follicles 
Follicle produces oestrogen 
Oestrogen increases - causes positive feedback 
Inhibin increases 
When LH rises more than FSH = ovulation

Question 11

What is the role of inhibin?

Answer 11

Prevent more than one follicle developing

Question 12

What happens to the oocyte during ovulation?

Answer 12

Meiosis 1 completes
Meiosis 2 starts
Mature oocyte extruded through capsule of the ovary

Question 13

When does the luteal phase occur?

Answer 13

After ovulation

Question 14

How long does the luteal phase take?

Answer 14

14 days

Question 15

What happens in the luteal phase?

Answer 15

Follicle luteinised
Follicle secretes large amounts of oestrogen and progesterone
Follicle produces inhibin

Question 16

What happens if the oocyte is not fertilised?

Answer 16

Oestrogen, progesterone + inhibin levels drop

Question 17

What is the uterine cycle?

Answer 17

Response of the uterus + endometrium in response to hormones

Question 18

What are the stages of the uterine cycle?

Answer 18

Proliferative stage
Secretory stage
Menstrual stage

Question 19

What is the histology of the uterus in the early proliferative stage?

Answer 19

Glands are sparse + straight

Question 20

What is the histology of the uterus in the late proliferative stage?

Answer 20

Functional layer doubled

Glands coiled

Question 21

What is the histology of the uterus in the early secretory stage?

Answer 21

Endometrium maximum thickness

Very pronounced coiled glands

Question 22

What is the histology of the uterus in the late secretory stage?

Answer 22

Glands have saw tooth appearance

Question 23

What happens in the proliferative stage?

Answer 23

Endometrium proliferates in response to oestrogen

Question 24

What happens in the secretory stage?

Answer 24

Glands become secretory - due to progesterone

Endometrium prepares to shed lining

Question 25

What happens in the menstrual stage?

Answer 25

Endometrial lining is shed

Question 26

What is the normal duration for a menstrual cycle?

Answer 26

21-35 days

Question 27

What factors can affect the menstrual cycle?

Answer 27

Pregnancy 
Lactation 
Hormonal contraception 
Emotional stress
Low body weight