Female Reproductive System

The female reproductive system

It is a system that produces ova (egg cells), provides an environment for fertilisation and foetal development, and secretes vital hormones.

Role of the ovaries

• They make eggs and hormones like; Oestrogen and progesterone.

• The hold undeveloped eggs.

• They release an egg into the fallopian tube as part of a woman’s cycle.

Ova

Undeveloped eggs

Ovum

Mature egg

Ovulation

When an egg is released

Fallopian Tubes

• They connect the ovaries to the uterus.

• They are covered in small hairs (cilia) which help move the egg along.

Uterus

Also known as the womb, is a hollow shaped muscular bag, where a fetus or baby grows.

Lining of the uterus

• Also known as endometrium, sheds and thickens as part of the menstrual cycle.

• Where an egg will be implanted.

Cervix

• A strong ring of muscle at the lower part of the uterus, that opens into the vagina.

• During childbirth, the cervix expands about 4 inches, so that the body can travel from the uterus, through the vagina and into the world.

Vagina

• A tube that connects the uterus to the outside of the body-(vaginal opening).

• Folds of skin called the labia, meet at the entrance of the vagina from the vulva.

• Urine passes through the urethra, which opens into the vulva but this is seperate from the vagina.

Menstrual Cycle

The cycle in which women have their periods and are fertile to conceive.

Characteristics of the menstrual cycle

• Girls begin their periods around the age of 12 and continue till menopause around the age of 50

• They cycle lasts around 28 days

The Menstrual Cycle: Key Phases

1. Menstrual Phase: Days 1-5

2. Follicular Phase: Days 1-13

3. Ovulation: Day 14

4. Luteal Phase: Days 15-28

The Menstrual Cycle Phases in detail

1. Menstrual Phase (Day 1-5)
   — Shedding of the uterine lining
   — Causes menstrual bleeding (3-5 days typically)
   — This phase is triggered by a drop in oestrogen and progesterone
   
   

2. Follicular Phase (Day 1-13)
   — Overlaps with the menstrual phase
   — The pituitary gland produces FSH, which stimulates ovarian follicles
   — As the follicles mature, they start the secretion of oestrogen
   — One follicle matures into a dominant follicle
   — Oestrogen levels begin to rise, causing endometrium to start rebuilding
   
   

3. Ovulation (Day 14)
   — Release of the dominant follicle, the most mature egg from ovary
   — Triggered by a surge in LH, produced by the pituitary gland
   — Egg survives - 24 hours for fertilisation
   — Most fertile period of the cycle
   
   

4. Luteal Phase (Day 15-28)
   — Ruptured follicle forms corpus luteum
   — Starts the secretion of progesterone, which maintains uterine lining
   — If fertilisation does not occur, corpus luteum degenerates
   — Hormone levels fall, causing the menstrual cycle to restart (menstruation begins)

Corpus Luteum

• The ruptured follicle or ‘egg shell’, from which the egg was released

• It is yellow in colour