2.3) the biology of controlling fertility

infertility treatments and contraception are based on the ...

biology of fertilisation

what type of fertility do males show ?

continious

what type of fertility do males show ?

cyclical

why is male fertility described as continious?

men continuously produce sperm in their testes

why is female fertility described as cyclical ?

women are only fetile for a few days each mentrual cycle, lasting approx 5 days

a womens body temperture rises by around _____ after ovulation and her cervical mucus becomes _______ and ______

0.5
thin
watery

Infertility factors that could be linked:

Age, genetics and disease.As well as health and lifestyle choices eg anorexia, smoking, stress and obesity.

what are the 4 treatments for infertility?

-stimulating ovulation
-artificial insemination
-intracytoplasmic sperm injection (ICSI)
-in vitro fertilisation (IVF)

expain stimulating ovulation to treat fertility

ovulation is stimulated by drugs that prevent the negative feedback control effect of oestrogen on the FSH secretion.

other stimulating ovulation drugs mimic the action of ...

what can these drugs cause?

mimic the action of FSH and LH

these drugs can cause super ovulation that can result in multiple births or can be used to collect ova for In Vitro fertilisatio (IVF)

explain WHAT artificial insemination is for

a procedure carried out when a male has a low sperm count

explain artifical insemintation

If a partner is a sterile donor they may be used to they may be used to provide the semen

1. Several samples of semen are collected over a period of time

2. When there is enough sperm in the sample, it is then inserted into the female reproductive tract

expain Intro-cytoplasmic sperm injection (ICSI)

In this procedure the head of the sperm is drawn into a needle and is injected directly into the egg to achieve fertilisation

when is intro-cytoplasmic sperm injection carried out ? (ICSI)

when a male has a low sperm count

explain when In vitro fertilsation is carried out

carried out when oviducts are blocked

explain how In vitro fertilisation (IVF) is carried out?

1) patient is given hormone treatment to stimulate egg cell production

2) eggs are removed from ovaries

3) eggs are mized with the sperm in a culture dish

4)the fertilisaed eggs (zygotes) are incubated until they have formed at least 8 cells

5) the incubated fertilsed eggs (8 cells) are then transferred to the uterus for implantation

6) additional fertilised eggs can be forzen until a later date

what are the physical methods of contraception>

-condoms
-intra uterine devices
-sterilisation procedures

explain condoms

made from thin latex and are designed to stop semen coming into contact with his sexual partner

explain inter-uterine devices

IUD can stop a fertilsed egg from implanting in the uterus, it also alters cervical mucus preventing sperm from reaching the eggs

explain female sterilisation

tubual ligation - involves cutting and tying of the two oviducts.
this prevents sperm from reaching the egg

explain male sterilisation

vasectomy - involves cutting and tying the two sperm ducts, preventing the release of sperm during sexual intercourse

what are the chemical methods of contraception

-the contraceptive pill ( oest & prog pill)

-the mini pill (prog only)

-morning after pill

explain how contraceptive pill works (oest & prog)

it contains a combination of oestrogen and progesterone which mimic the negative feedback preventing the release of FSH and LH from the pituitary gland

explain the mini pill (prog)

pill causes the thickening of cervial mucus , sperm cannot easily swim through this mucus

explain the morning after pill

it can be taken up to 3 days after unprotected sex to prevent pregnancy,

it prevents implantation and there is delayed ovulation