1 / 14

Sex determinants

Sex determinants. Dr. Sanjaya Adikari Dept. of Anatomy. Objectives. Explain the role of sex chromosomes in sex determination Highlight the role of Y chromosome in fetal sex determination. Male. Female. chromosomal sex. cell. XX. XY. gonadal sex. Ovaries. Testicles. gonads.

talli
Télécharger la présentation

Sex determinants

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sex determinants Dr. Sanjaya AdikariDept. of Anatomy

  2. Objectives • Explain the role of sex chromosomes in sex determination • Highlight the role of Y chromosome in fetal sex determination

  3. Male Female chromosomal sex cell XX XY gonadal sex Ovaries Testicles gonads external genitalia Labia majora & minora vulva, vagina Penis, scrotum assigned sex general appearance Facial hair dress Breasts dress

  4. Chromosomal sex • Determined at the time of fertilization • 46, XX female • 46, XY male • What determines the sex? • Presence of two ‘X’ chromosomes? • Presence/absence of ‘Y’ chromosome?

  5. Individuals resulting from non-disjunction of sex chromosomes

  6. XY XX nondisjunction Y XX O X XXX XXY XO OY Super females Klinefelter’s syn Turner’s syn lethal Can one get XYY?

  7. Live with‘X’&Sex with‘Y’

  8. indifferent stage female male External genitalia

  9. Role played by hormones XY XX ovaries testicles androgens oestrogen male external genitalia female external genitalia male secondary sex characteristics female secondary sex characteristics

  10. Determining the number of X and Y Sex chromatin Barr body for X F body for Y

  11. Barr body Barr body • Condensed inactive ‘X’ in interphase nuclei • Near the nuclear membrane • All ‘X’ in addition to one ‘X’ become BB’s

  12. F body F body • Fluorescence stained ‘Y’ • This ‘Y’ is active

  13. ?? XX XXY XO XYY One BB No FB One BB One FB No BB No FB No BB Two FB

  14. References • http://www.people.virginia.edu/~rjh9u/sexdet.html • http://www.dushkin.com/connectext/psy/ch10/biodet.mhtml • http://www.aaa.dk/TURNER/ENGELSK/XYY.HTM#name • Review of medical physiology by William F. Ganong • Medical embryology by Jan Langman

More Related