HUMAN REPRODUCTION 140

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Anonymous
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7276
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HUMAN REPRODUCTION 140
Updated:
2010-02-18 09:32:54
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SEXUAL DIFFERENTIATION
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IB 140
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  1. Human Diploid cells have _____chromosomes in _____pairs
    • -46 in 23 pairs
    • (22 are nonsex chromosomes)
    • (1 pair of sex chromosomes)
  2. X CHROMOSOME:
    • -Large
    • Many essential genes not related to sex determination
    • -Early embryonic development
    • -Barr Body (sex chromatin) represents inactivated X Chromosome
  3. Y CHROMOSOME:
    • -Small
    • -Genes in Y chromosome haessential roles in spermatogenesis
    • -Short arm of Y Chromosome contains a sex-determining region of the Y (SYR) gene that encodes a testes determining factor
    • -If SRY is present an embryo develops testes and becomes a male
    • -If SRY is absent the embryo becomes a female.
    • -Contains mores than 20 genes or gene families that affect spermatogenesis and other aspects of male growth
    • -20 genes as well as the SRY gene are on the part of the Y chromosome that does NOT trade genes with parts of X Chromosome
    • -Infertile men could have delted 1 of the 10 genes on the Y chromosome that control various stages of spermatogenesis
  4. Sex Influenced Trait:
    ex: baldness
    • -on human x chromosomes there are genes that are sex-linked that produce phenotypic effects that are called sex-linked traits
    • -Males require only one allele for baldness becuse they have more circulating levels of testostorone
    • -Females must be Homozygous for bald alleles because there is less circulating testostorone in females.
  5. SEXUAL DIFFERENTIATION IS DETERMINED BY:
    • -chromosome and os established when an egg fertilized by a sperm
  6. Sexually Indifferent Stage:
    • *Period when gonads , sex accesory ducts, and external genitalia of both sexes are identical
    • *Genital ridges in abdominal cavity of embryo develop into indifferent gonads during the 5th week of development
    • *During 6th Week the embryo has indifferent sex accesory ducts consisting of 2 pairs of ducts
    • *LASTS UNTIL END OF 7TH WEEK
    • *Wolffian Ducts derived from the ducts of the primitive embryonic kidney
  7. GONADAL SEX DIFFERENTIATION:
    • *(4th or 5th week) Germ cells begint o arrive at and penetrate the different gonads
    • *Primordial germ cells arise in the region of the developing allantois and migrate by amoeboid movement along the embryonic gut to the indifferent gonads
  8. OOVARIAN DEVELOPMENT:
    If Y chromosome is not present
    • *Gonads develop into ovaries
    • *PRIMORDIAL GERM CELL DEVELOP INTO OOGONIA WITHIN CORTICAL CORDS OF THE OVARY AND MEDULLA DEGENERATES
    • *OOGONIA UNDERGO MITOTIC PROLIFERATION TO PRODUCE 600,000 by 8 weeks
    • *From -9 moth gestation the ocaries descend from abdominal position to reside in pelvic cavity
    • *At birth all female germ cells are Oocytes in follicles and each ovary has 1/2 to 1 million
    • *Number decreases with age cause of atresia
  9. TESTICULAR DEVELOPMENT:
    Presence of y chromosome in the primordial germ cells and gonadal cells
    • *results in testes development in 7th week
    • *Seminiferous tubules of the testes develop within the medullary cords of the medulla and cortex regresses
    • *testostorone producing Leydig cells appear between the medullary cords in week 9
    • *Placenta secretes LH-like gonadotroping called hCG whuch may pass into male fetus and stimulate Leydig cells to begin secreting testostorone.
    • *From 3-9 Month of fetal life, the testes descend to scrotum
    • * testticular descent under control of MIS and TESTOSTORONE TURNED TO DHT
  10. DAX1
    * Gene in X chromosome that is actively involved in ovary formation
  11. Embryos of each sex contain both _________ducts and _____________duct systems until the 7th week of development.
    • +wolffian
    • +Mullerian
  12. Wolffian duct turns to
    *epididymus, vas deferens, seminal vesicles, and ejaculatory duct
  13. Vasa Efferentia:
    - Develop from mesonephric tubules whuch lead to wolffian duct
  14. DHT
    -Stimulates part of urethra to develop into the prostrate fland and bulbourethral glands.
  15. HOMOLOGIES:
  16. HERMAPHRODITISM:
  17. ABNORMALITIES IN PLOIDY NUMBER:
  18. POLYPLOIDY:
  19. ANEUPLOIDY:
  20. AUTOSOMAL TRISOMY:
  21. AUTOSOMAL TRISOMY 21:
  22. MATERNAL AGE AND CHROMOSOMAL ABNORMALITIES:
  23. SEX CHROMOSOME TRISOMY:
    XXX,XXY, and XYY
  24. SEX CHROMOSOME MONOSOMY:
    TURNERS SYNDROME:
  25. FRAGILE X SYNDROME:
  26. PSEUDO INTERSEX:
  27. TESTICULAR FEMINIZATION:
  28. PSEUDOINTERSEX:
    5ALPHA REDUCTASE DEFICIENCY
  29. PSEUDOINTERSEX:
    5ALPHA REDUCTASE DEFICIENCY IN GUEVEDOCES
  30. PSEUDOINTERSEX:5ALPHA REDUCTASE DEFICIENCY IN GUEVEDOCES
  31. MALE SEX DEVELOPMENT ABNORMALITIES:
  32. FEMALE SEX DEVELOPMENT ABNORMALITIES:

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