Female reproductive system - physiology

Question 1

What is puberty?

Answer 1

The age at which the internal reproductive organs reach maturity, usually between the ages of 12 and 14

Question 2

What is the hormonal trigger for puberty?

Answer 2

Hypothalamus releases luteinising hormone releasing hormone (LHRH)
LHRH acts on the anterior pituitary gland, causing it to release follicle stimulating hormone (FSH) and luteinising hormone
FSH and LH cause the ovaries to secrete oestrogens

Question 3

What are oestrogens responsible for?

Answer 3

Secondary sex characteristics

Question 4

What are the secondary sex characteristics in females?

Answer 4

Maturation of the uterus, uterine tubes and ovaries
Development and enlargement of the breasts
Growth of pubic and axillary hair
Increase in height
Widening of the pelvis
Increased fat deposition in the subcutaneous tissue, especially at the hips and breasts

Question 5

What is menarche?

Answer 5

Onset of menstruation

Question 6

What is menopause?

Answer 6

Ceasing of menstruation

Question 7

What is menstruation?

Answer 7

A ‘period’ of vaginal bleeding as the lining of the uterus sheds and is passed through the vagina

Question 8

What is the reproductive cycle (menstrual cycle)?

Answer 8

A series of events, occurring regularly in females every 26-30 days throughout the childbearing period between the menarche and menopause

Question 9

What does the reproductive cycle consist of?

Answer 9

A series of changes taking place concurrently in the ovaries and uterine lining, stimulated by changes in hormones

Question 10

What happens in the ovaries in uterus?

Answer 10

BY 20 weeks gestational age, primary ova are formed in the developing ovaries of the foetus (over 1 million are present at time of birth)
These follicles are immature, their development is halted until menarche

Question 11

What happens in the ovaries during the reproductive cycle?

Answer 11

During each cycle, one follicle matures
Maturation is controlled by the hypothalamus (secretes LHRH) and the anterior pituitary gland (releases gonadotrophins (FSH and LH).

Question 12

What does the follicle do during the first half of the cycle?

Answer 12

Secretes increasing amounts of oestrogen while the ovum is developing in it

Question 13

What does the corpus luteum secrete?

Answer 13

After ovulation, it secretes progesterone primarily with some oestrogen and inhibin.

Question 14

What happens to the ovarian follicle before ovulation?

Answer 14

The follicle develops from an immature (primordial) follicle to a mature (graafian) follicle
The follicle is filled with follicular fluid which increases
The graafian follicle migrates from the cortex to the surface of the ovary

Question 15

What happens to the ovarian follicle during ovulation?

Answer 15

On day 14 of the cycle, the follicle ruptures releasing the ovum into the peritoneal cavity
It is ‘caught’ by the fimbriae at the end of the uterine tube
It is propelled by cilia, along the uterine tube towards the uterus
Body temperature rises by 1 degree celsius

Question 16

What happens to the ovarian follicle after ovulation?

Answer 16

Corpus luteum develops which secretes progesterone
Progesterone causes LH and FSH to fall
If the ovum is not fertilised, LH leads to degeneration and death of the corpus luteum
If the ovum is fertilised, the corpus luteum continues to secrete hormones for 3-4 months

Question 17

What happens to the uterus during days 1-4 of the reproductive cycle (menstrual stage)?

Answer 17

Progesterone and oestrogen levels fall and the functional layer of the endometrium is shed in menstruation as the myometrium contracts

Question 18

What happens to the uterus during days 5-14 of the reproductive cycle (proliferative stage)?

Answer 18

The maturing ovarian follicle stimulates the thickening (regrowth) of the functional layer of the endometrium in preparation for the reception of the fertilised ovum
The endometrium becomes very vascular and rich in mucus-secreting glands
(ends at ovulation)

Question 19

What happens to the uterus during days 15-28 of the reproductive cycle (secretory stage)?

Answer 19

Progesterone from the corpus luteum stimulates the endometrium to become very oedematous and the secretory glands produce increased amounts of watery mucus
This assists the motile spermatozoa through the uterus to the uterine tubes where the ovum is usually fertilised