The biology of Controlling fertility Flashcards
Compare fertility in males and
females
Males are continuously fertile
whereas females are cyclically fertile
What does cyclical fertility mean?
Women are only fertile for a few
days during each menstrual cycle
When is the fertile period in
females?
The day before, the day of and the
day after the surge in LH which
triggers ovulation
What happens to cervical mucus
during the fertile period?
The mucus becomes thin and
watery
State how body temperature is
affected by ovulation
After ovulation the body
temperature rises by around 0.5C
Name 4 treatments for infertility
In-vitro fertilisation (IVF)
Intra-cytoplasmic sperm injection(ICSI)
Artificial insemination
Stimulating ovulation
How can ovulation be stimulated?
By taking drugs that prevent the negative feedback effect of
oestrogen on FSH secretion or others that mimic the action of
FSH and LH
What can happen when taking drugs
that mimic the action of FSH and
LH?
Super ovulation
-ova can be used in IVF programmes
In which infertility treatment are
several samples of semen collected
over a period of time?
Artificial insemination
When is artificial insemination
particularly useful?
low sperm count
sterile (donor)
When is intra-cytoplasmic sperm
injection (ICSI) used to treat
infertility?
spermare defective
low in number
Describe the process of ICSI
The head of a single sperm is drawn
into a needle and injected directly
into the egg to achieve fertilisation
Describe the process of IVF
treatment
EMIT
Eggs are surgically removed from ovaries
following hormone stimulation
mixed with sperm in a culture dish to form
zygotes,
incubated until they form At least 8 cells,
transferred to the uterus for implantation.
Name a procedure that may be
carried out on zygotes prior to
implantation using IVF treatments
& explain why it is used
Pre-implantation genetic diagnosis
(PGD)
identify single gene disorders & chromosomal abnormalities
Name the two forms of
contraception
Physical and chemical
Give examples of barrier methods
used in contraception and describe
how these prevent fertilisation
Condoms
diaphragms
cervical caps
-prevent sperm and eggs meeting
Describe how intra-uterine devices
prevent fertilisation occurring
affect the motility and viability of sperm
affect the endometrial lining,
-reducing the
chances of implantation
Describe how sterilisation
procedures prevent fertilisation
sealing the oviducts of females or sperm ducts of males
Give three examples of chemical
contraception
Oral contraceptive pill,
progesterone-only (mini) pill
morning after pill
Describe how the oral contraceptive
pill prevents fertilisation
COI
This pill prevents ovulation or
implantation
Describe how the progesterone-only
(mini) pill prevents fertilisation
It causes thickening of the cervical mucus,
prevents sperm from entering the uterus
Describe how the morning-after pill
prevents fertilisation
It prevents ovulation or implantation
What does PGD do
identify single gene disorders and chromosomal abnormalities
