BIOL 1102 Lecture Notes - Lecture 18: Fallopian Tube, Ectopic Pregnancy, Twin
Document Summary
Fertilization: combining of egg and sperm: external fertilization. Release millions of gametes in water, hope they find each other. Steps in fertilization: sperm penetrates egg coat. Digests through egg coat to egg cell membrane: sperm and egg cell membrane fuse, fertilization membrane. Barrier that prevents a second sperm from entering the egg: sperm and egg nuclei fuse, egg implants into lining of uterus. Fraternal twins: two or more different eggs are fertilized at the same time. Identical twins: one fertilized egg splits into two genetically identical eggs. Multiple births: can be fraternal, identical, or a combination. Humans typically have one baby at a time. Where does fertilization occur: fallopian tubes. How long is the egg in the fallopian tubes: 12-24 hours. When are women most fertile: days 10-20 of the menstrual cycle. How many pregnancies end in miscarriage: about 1 in 6. Ectopic pregnancy: fertilized egg implants somewhere other than uterus. Preeclampsia: high blood pressure during pregnancy.
