2.3- the biology of controlling fertility

Question 1

what type of fertility do men have and why is this?

Answer 1

continuous fertility

continually produce sperm in their testes

Question 2

what is cyclical fertility and what does it lead to?

Answer 2

when women are only fertile for a few days during each menstrual cycle

leads to a fertile period

Question 3

2 things that identify the fertile period

Answer 3

womans body temperature increases around 0.5° after ovulation

cervical mucus becomes thin and watery

Question 4

what does thin and watery cervical mucus allow for?

Answer 4

gives sperm easy access to the female reproductive system

Question 5

how long does the fertile period last?

Answer 5

1-2 days

Question 6

what happens after the third recording of higher temperature?

Answer 6

unfertilised egg is disintegrated

Question 7

4 treatments for infertility

Answer 7

stimulating ovulation

artificial insemination

intra-cytoplasmic sperm injection (ICSI)

in-vitro fertilisation (IVF)

Question 8

how does stimulating ovulation work?

Answer 8

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

Question 9

what do other ovulatory drugs do and what do they cause?

Answer 9

mimic the action of FSH and LH

cause super ovulation that can result in multiple births or be used to collect ova for in-vitro ovulation programmes

Question 10

what does artificial insemination involve?

Answer 10

several samples of semen are collected over a period of time

Question 11

when is artificial insemination useful?

Answer 11

when male has a low sperm count

Question 12

how does intra-cytoplasmic sperm injection work?

Answer 12

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

Question 13

when is intra-cytoplasmic sperm injection useful?

Answer 13

when mature sperm are defective or very low in number

Question 14

what does in-vitro fertilisation intend to do?

Answer 14

solve infertility caused by a blockage in the oviduct

Question 15

6 steps of IVF

Answer 15

woman is given hormonal treatment to stimulate multiple ovulation

surgical procedure employed to remove several of these eggs from her ovary

eggs mixed with sperm in culture dish to allow fertilisation to occur (ICSI can be used)

fertilised eggs incubated in culture dish for 2-3 days to allow cell division to occur and they have formed at least 8 cells

a few embryos are chosen and then inserted via the vagina into the mothers uterus

remaining embryos frozen and stored if a second attempt at implantation is needed

Question 16

what can IVF be used in conjunction with and what 2 things can they identify?

Answer 16

pre-implantation genetic diagnosis

identify single gene disorders and chromosomal abnormalities

Question 17

when is pre-implantation genetic diagnosis used in IVF and what happens?

Answer 17

before stage 5 takes place

one or two cells may be removed and tested for genetic abnormalities

Question 18

2 forms of pre-implantation genetic diagnosis

Answer 18

pre-implantation genetic screening (PGS)

pre-implantation genetic diagnosis (PGD)

Question 19

what is pre-implantation genetic screening?

Answer 19

non-specific approach

checks embryo for single gene disorders and common chromosomal abnormalities

Question 20

what is pre-implantation genetic diagnosis?

Answer 20

specific approach

check for a known chromosomal or gene defect

Question 21

what do pre-implantation genetic screening and diagnosis allow experts to do?

Answer 21

select which embryos should not be allowed to be placed in the mothers endometrium

Question 22

2 reasons for PGS and PGD

Answer 22

offer reassurance to couples who would otherwise be at high risk of producing children with serious genetic disorders

reducing the frequency of genetic diseases and disorders is a great benefit to society as a whole

Question 23

reason against PGS and PGD

Answer 23

start of eugenics whereby humans would be subjected to selective breeding in order to improve the quality

Question 24

what is contraception?

Answer 24

intentional prevention of conception by natural or artificial means

Question 25

3 **physical** contraceptives

Answer 25

barriers intra-uterine devices sterilisation

Question 26

**what** are barrier methods?

Answer 26

devices that physically block the ability of sperm to reach an ovum

Question 27

3 **barrier** methods

Answer 27

condom diaphragm cervical cap

Question 28

what is a **condom**?

Answer 28

rubber sheath that fits over the mans penis or female condoms can be worn inside the vagina

Question 29

what is the **diaphragm**?

Answer 29

dome shaped rubber cap that is inserted into the woman's vagina to block the cervix before sexual intercourse

Question 30

what is the **cervical cap**?

Answer 30

rubber structure that fits tightly around the cervix and can be left for a few days

Question 31

what are **intra-uterine devices** and what do they **do**?

Answer 31

t-shaped structure that is fitted into the uterus for many months or years to prevent the implantation of an embryo into the endometrium

Question 32

what is sterilisation in **males** called and what does it **involve**?

Answer 32

vasectomy involves cutting and tying two sperm ducts to prevent sperm being released during sexual activity

Question 33

what happens to sperm produced **after** a vasectomy?

Answer 33

undergo phagocytosis and are destroyed

Question 34

what is sterilisation in **females** called and what does it **involve**?

Answer 34

tubal ligation involves cutting and tying two oviducts to prevent eggs meeting sperm and reaching the uterus

Question 35

3 **chemical** methods of contraception

Answer 35

oral contraceptive pill progesterone only pill morning after pill

Question 36

what does the oral contraceptive pill **contain** and what do these things **do**?

Answer 36

contains combination of synthetic oestrogen and progesterone mimics negative feedback that prevents release of FSH and LH from the pituitary gland

Question 37

what happens when **little** or **no** **FSH** is present as a result of the **oral contraceptive pill**?

Answer 37

follicle maturation remains inhibited and ovulation fails to occur

Question 38

what happens on **week 4** of the oral contraceptive pill and **why**?

Answer 38

placebo is taken or no pill at all allows levels of oestrogen and progesterone to drop and menstruation to occur

Question 39

what is the function of the **progesterone only pill** and what is its effect?

Answer 39

causes thickening of the cervical mucus reduces viability of sperm and their access to the uterus

Question 40

what 2 things does the morning after pill **contain**?

Answer 40

high doses of progesterone and oestrogen

Question 41

what do women use the morning after pill **for**?

Answer 41

after unprotected sexual intercourse to prevent implantation from occurring if fertilisation has taken place unintentionally

Question 42

**when** should the morning after pill be taken?

Answer 42

effective up to 72 hours after unprotected sex

Question 43

what **other function** does the morning after pill have?

Answer 43

inhibits ovulation

Question 44

what is the only form of contraception that **protects against STIs**?

Answer 44

external male and internal female condoms