Practise IB Biology SL D3.1.7 by tracing hormone stimulation, egg collection, fertilization outside the body and transfer of embryos to the uterus.
Embryos that are produced by in vitro fertilization can be screened for genetic disease. Outline the process of in vitro fertilization, including one example of a situation when it is used.
drugs used to down-regulate the menstrual cycle;
FSH injected to stimulate many follicles to develop;
HCG injected to cause the follicles to mature;
eggs are harvested/extracted (from the follicles/ovaries);
semen sample produced/collected;
semen is processed to concentrate it / healthy sperm selected (swim-up test given);
ICSI/IntraCytoplasmic Sperm Injection where sperm is directly injected into egg when low numbers of motility is a factor;
semen mixed with eggs in a dish/outside the body to allow fertilization;
incubated / kept at 37∘C/ allows embryos to develop (sufficiently for implantation);
dish examined to choose healthiest embryo;
embryos placed in uterus/oviduct (using a catheter/long plastic tube);
one/two/three/up to four (in some countries) embryos implanted;
pregnancy test/scan used to see if procedure has been successful;
(used in cases of) blocked oviduct / low sperm count / need for genetic screening / infertility / cannot become pregnant / need for donor embryo;