reproduction
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28 terms
Terms | Definitions |
|---|---|
 gametogenesis | process of forming gametes through meiosis |
| gametes | sex cells constitute both sperm and egg cells |
| spermatogenesis | occurs in male individuals results in the formation of 4 functional spermatoza |
| oogenesis | occurs in female individuals results in the formation of 1 functional ovum and 3 nonfunctional polar bodies |
| gestation | period of time in which all stages of development occur |
| fertilization | union of the sperm and egg nucleus: formation of a zygote |
| implantation | attachment/penetration of the conceptus into the uterus |
| zygote | a fertilized ovum sperm vehicle does not enter egg only fuse at shell membrane transferring 23 chromosomes |
| conceptus | stage that implants into uterus developmental stages occurring after the zygote through two weeks |
| 3 required events for conceptus | ovum (oogenesis) fertilization implantation |
| spermatozoa | live 12 to 48 hours |
| embryo | developmental stages occurring from the 3rd week through the 8th week stage where organogenesis occurs |
| organogenesis | formation of specific organs in the developing embryo (one chance to form) critical stage for any type of birth defect |
| fetus | developmental stages occurring from the 9th week through birth. stage of growth for 29 weeks or 11 weeks at gestation |
| identical twins | twins that develop from a single ovum fertilized by a single spermatozoa always the same sex! |
| fraternal twins | twins that develop from two different ova that are fertilized by two different spermatozoa can be same sex or opposite sex! |
| dizygotic (fraternal) | 2 egg division 2 single zygote 2 different humans |
| monozygotic (identical) | 1 egg division same zygote 2 humans |
| 2 primary sources of stem cells | adult and embryonic |
| stem cells | they are undifferentiated cells they can potentially be turned into any human tissue |
| siamese | monozygotic split started but did not finish. nueraltube elongation splits 2 heads 2 CNS 1 body |
| elephant | longest gestation 104 weeks (2 yrs) |
| human | gestation is 40 weeks |
| 4 types of stem cells | totiopotent pluripotent multipotent unipotent |
| totipotent | totus - entire can create entire organisms 1st 3 divisions of conceptus cloned cows |
| pluripotent | pluri - several/any create parts of an organism human organs |
| multipotent | multi - many/limited to subtypes make any type of blood cells and blood cells only |
| unipotent | uni - one can only make one type of cell cells in testes |
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