Human Reproductive Flashcards
Ovary
Produces an egg every 28 days
Oviduct
Where fertilisation takes place
Uterus wall
Placenta will develop supply foetus with food and oxygen
Testes
Produces sperm cells
Urethra
Transport sperm and urine out of body
Scrotum
Sac that holds and protects testes
Sperm tube
Structure that carries sperm from testes to penis
Prostate gland
Male gland that adds fluid to nourish the sperm
Cervix
Opening of the uterus
Sperm cells
Specialised cells formed by meiosis and are adapted to their function by having a haploid nucleus, mitochondria for energy production and a flagellum for swimming
Sperm cell tail
Fagellum
Fertilisation
Takes place in the oviduct when the haploid sperm and egg nuclei fuse to give a diploid zygote
What happens after the zygote is formed
Divides by mitosis many times to from a ball of cells as it travels down the oviduct to the uterus
After implantation
After implantation in the uterus lining, the embryo then differentiates to produce a variety of tissues and organs
How is placenta adapted for diffusion
Large SA for exchanging dissolved nutrients, oxygen, carbon dioxide and urea.
Villi
Increase the SA over which the exchange of materials between the mother and the foetus can occur.
How are substances carried to the foetus
Blood vessels in the umbilical cord
What cushions the foetus
Amnion and amniotic fluid
Male sex Hormone
Testosterone- produced by testes
Female sex Hormone
Oestrogen - produced by ovary
Secondary sexual characteristics in males
🍄body hair and public hair develops
🍄body becomes more muscular
🍄voice deepens
Secondary sexual characteristics in females
🍄hair growth in public regions and armpits
🍄hips widen, breasts develop
🍄menstrulation starts
Contraception, mechanical
Condom Prevents sperm from entering the females body ✔️protects against STI ✔️easy to obtain ❌can be unreliable if not used properly
Diaphragm
Covers cervix so sperm cannot pass into the uterus and into the oviduct
✔️reliable when used properly
❌does not protect against STIs
Problem with STIs
HIV lead to AIDS
Some of which can lead to infertility if left untreated eg chlamydia
Contraception, Chemical
Contraceptive pill Change hormone levels and stop the development of the ovum ✔️very reliable when used properly ❌side effects eg weight gain ❌does not protect against STIs
Contraceptive implant
Releases progestin prevents eggs being released
✔️last up to 3 years
❌does not protect against STI
Contraception- Surgical
Vasectomy
Sperm ducts cut so sperm cannot travel into urethra
✔️exceptionally reliable
❌difficult to reverse. Does not protect against STIs
Female sterilisation
Cutting of oviducts prevent ovum meting sperm
✔️exceptionally reliable
❌difficult to reverse. Does not protect against STIs
Problem with contraception
Raise ethnical issues
Menstrual cycle
1-7 during menstruation , lining uterus wall breaks down and leaves body via vagina as menstrual blood
8-14 lining of the uterus starts to repair itself and thicken, in preparation for implantation if a pregnancy occurs
14 ovulation occurs; ovum releases from ovary and travels into oviduct
15-28 if egg fertilised in oviduct, resulting embryo implant in thickened lining of uterus and menstruation will stop until after baby born
If no pregnancy should occur the thickened lining will start to break down again and will be shed during menstruation at the start of the next menstrual cycle
Role of oestrogen in menstrual cycle
🍄produced by ovaries
🍄causes repair and development of uterus wall
🍄interacts with other hormones to ensure that only one egg matures per cycle and that this mature egg is released from the ovary
Role of progesterone in menstrual cycle
🍄produced by the ovaries
🍄maintains the lining of the uterus during the middle part of the cycle and during pregnancy
🍄prevents further release of eggs when levels are high
Fertility problems
🍄failure of ovary to produce eggs
🍄oviducts may be blocked or twisted, possibly due to infection
🍄lining of uterus does not develop properly to enable implantation to occur
🍄vagina may be to hostile to sperm entering eg lining too acidic
🍄males may not produce enough sperm
🍄Sperm may have poor mobility
IVF stand for
In vitro fertilisation
Steps 1 to IVF
Once natural cycle stopped, woman is given daily injections of fertility hormones for about 12 days.
The Hormone will increase number of eggs that the ovaries produce. Means more eggs collected and fertilised
Step 2 to IVF
eggs collected under ultrasound guidance. Involves a needle being inserted through the vagina and into each ovary. The eggs are then collected through the needle. Occurs before ovulation, egg easier to find while still in ovary
Step 3 to IVF
Man asked to provide a sperm sample
Step 4 to IVF
Eggs that have been collected are mixed with the sperm in a Petri dish in the laboratory. After 16-20 hrs they’re checked to see if any have been fertilised. The cells that have been fertilised undergo mitosis to from a ball of cells, in the lab, for 1-5 days. Best one or two embryos chosen for transfer
Step 5 of IVF
Embryos are introduced to the uterus via the vagina.
HFEA recommend max of 2 embryos replaced in the womb. Multiple embryo replacement carry risk of multiple births. Associated with a significant increased risk of premature labour.
Any embryo left are frozen for future IVF attempts
