Hormonal coordination (menstrual cycle)

Question 1

Explain the menstrual cycle, including what happens in a pregnancy:

Answer 1

1. normally 28 days long, day 1 is where the lining of the uterus (blood/tissue) breaks down and a woman begins her period. This is menstruation and lasts about 4 days.
2. once finished, the uterus lining stats to repair and its thickness builds up again.
3. day 2, a mature egg (ovum) is released from an ovary into the oviduct. This is ovulation and is why cramps are experienced.
4. the ovum travels through the oviduct, where it may meet a sperm and become fertilised, the egg divides via mitosis, creating an embryo.
5. the embryo travels into the uterus and implants itself into the lining, where it receives the nutrients and oxygen from the mother.
6. if fertilisation doesn’t occur, the lining will break down and pass out, starting a new period that flushes out the unfertilised egg.

Question 2

State the hormones involved in menstruation in order:

Answer 2

-FSH
-oestrogen
-LH
-progesterone

Question 3

What is FSH’s impacts on the reproductive system and other hormones: Where is it produced?

Answer 3

pituitary gland

RS-
it makes the egg mature

H-
sends signals to the ovaries to produce oestrogen

Question 4

What is oestrogen’s impacts on the reproductive system and other hormones: Where is it produced?

Answer 4

ovaries

RS-
builds the lining of the uterus up and stops the development of other eggs

H-
goes to the pituitary gland (bloodstream) stopping the production of FSH, and starting the production of LH

Question 5

What is LH’s impacts on the reproductive system and other hormones: Where is it produced?

Answer 5

pituitary gland

RS-
tells the ovaries to ovulate, turning the follicle that once developed the egg into a yellow body

H-
yellow bodies produces progesterone

Question 6

What is progesterone’s impacts on the reproductive system and other hormones: Where is it produced?

Answer 6

ovaries

RS-
builds up the lining of the uterus further to prepare for implantation of an embryo

H-
starts the production of FSH

Question 7

Describe methods that prevent pregnancy:

Answer 7

• oestrogen/ progesterone pills: both inhibit FSH so and LH so no more eggs mature and are ovulated.
• physical barriers: condoms and diaphragms prevent contact, keeping sperm from entering the reproductive system
• surgical methods: cutting/tying sperm ducts or oviducts prevents sperm being released or eggs being released.
• chemicals: these can kill sperm
• contraceptive implants/ injections

Question 8

What are some disadvantages of contraception methods:

Answer 8

• not always 100% accurate
• you need to be fully sure you don’t want kids (surgical)
• contraceptive pills cause high blood pressure and increased risk in breast cancer
• needs to be monitored/ taken regularly

Question 9

What are treatments to infertility:

Answer 9

• IVF (in vitro fertilisation)
• FSH and LH drugs (helps eggs mature and be released)

Question 10

Explain the process of IVF:

Answer 10

• the women is given FSH to produce mature eggs, then LH to release these mature eggs.
• the eggs are collected in a lab and are individually fertilised with the sperm of the man.
• the eggs are left in an incubated solution so they develop into embryos
• these embryos can be stored or used
• one or two embryos are implanted into her uterus for her to conceive

Question 11

What are the issues with IVF?

Answer 11

• expensive
• may not work
• several embryos are made so picking them may be unethical
• can lead to multiple pregnancies (higher chance), this increases the risk in stillbirths and premature births, this costs the hospital money to care for, and the ones who survive may have permanent disabilities.