3. Reproduction Flashcards
Ovary
Stores Ovum
Produces oestrogen and progesterone
Oviduct
Where fertilisation occurs
Uterus
Where implantation of embryo happens
Testes
Make sperm
Produce testosterone
Prostate gland
Releases chemicals to make the sperm active (semen)
SPerm tube or sperm duct
Tube that connects testes to urethra
Can be cut and tied during male sterilisation (vasectomy)
Placenta
Attached to the wall of the uterus
is adapted for diffusion by having a large surface area for exchanging dissolved nutrients, oxygen, carbon dioxide and urea
Have villi to increase the surface area
Umbilical cord
Connects placenta to foetus
Carries oxygen and glucose to foetus
Carries waste material from foetus
Amnion and amniotic fluid
The sac that surrounds foetus and protects it/cushions it from bumps
Menstrual cycle
28 day cycle in females in which the lining of the uterus changes in thickness depending on hormones oestrogen and progesterone
Role of oestrogen in menstrual cycle
Increases in levels from day 5 to 14
Causes lining of uterus to thicken and around day 14 levels highest and causes ovulation
Role of progesterone in menstrual cycle
Levels increase after ovulation
Continue to build up and maintain lining of uterus in preparation for implantation
Menstruation
Days 1 to 5 of menstrual cycle - lining of uterus breaks down
Reasons why a woman might be infertile
1 The ovaries do not produce an egg
2. The oviducts may be blocked or twisted, due to infection
3. Complications of some sexually transmitted inections
4. The lining of the uterus does not develop properly and so implantation can not occur
5. The vagina may be too thick or too acidic and so will be ‘hostile’ to the entering sperm
Reasons why a man might be infertile
- The male may not produce enough sperm or healthy sperm- this may be affected by smoking or excess alcohol
- Impotence
IVF treatment - what happens
Woman given hormones (fertility treatment) to cause the production of MULTIPLE ova
These ova are removed from ovaries (using a needle)
The ova and sperm are mixed in lab (in petri dish)
Fertilisation occurs
Fertilised eggs are then checked to make sure viable - are they dividing properly, no defects
Viable embryos are then placed inside the uterus of mother (usually only 2 embryos)
What happens to the unused embryos
Frozen - can be used again if process unsuccessful or want another child
can be donated to other people who are struggling to get pregnant or for medical research
What are the 3 types of contraception
Mechanical, Chemical, Surgical
In Mechanical contraception describe the advantages and disadvantages of this
Eg condom
Advantage - physical barrier that prevents sperm from entering vagina - therefore no chance of a sperm reaching and fusing with ovum
- protect from STIs
Disadvantage
If not used correctly can lead to pregnancy
Describe Chemical contraception
eg contraceptive pill or contraceptive implant
Advantage - no ova are released from the ovary due to hormones in pill/implant
no ova - no chance of sperm and ova joining in oviduct
Disadvantage - woman may forget to take pill/not take it at the same time each day so may lead to ovulation occurring and pregnancy
Does not protect agains STIs
Describe Surgical contraception
IN males- Male sterilisation or Vasectomy
Sperm tubes cut and ties
Advantage - no sperm released into vagina so no sperm to join with ovum
Disadvantage - permanent and difficult to reverse - person needs to be sure not want children/any more children
- does not protec against STIs
