{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Human Reproduction - HumanReproduction Gametogenesis(...

Info icon This preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
    Human Reproduction
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
    Stages of sexual reproduction Three distinct stages in this process: Gametogenesis (production of sex cells) Mating (getting the sex cells together) Fertilization (fusion of sex cells to form a  zygote) The processes of gametogenesis and fertilization are fairly similar among  all animals; however, there is considerable variation in mating  (question  to ponder: why might this be so?)
Image of page 2
    Gametogenesis Gametogenesis occurs in the gonads  (testes in males, ovaries in females) Testes (singular testis) produce sperm Ovaries produce ova (singular ovum) Gametes derived from germ cells  (rest  of body is comprised of somatic cells) Formation of germ cells begins during  embryonic development
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
    Spermatogenesis Germ cell   Spermatogonium (2n)  Primary spermatocyte (2n)   2 Secondary  spermatocytes 2(n)   4 Spermatids (n) Note: Meiotic reduction division occurs  during division between primary &  secondary spermatocytes; not  the second  meiotic division between secondary  spermatocytes and spermatids
Image of page 4
    Cytoplasmic contact required  during spermogenesis
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
    Oogenesis While sperm are produced continuously  throughout mature male reproductive  lifespan, human ova are all produced during  fetal development A few hundred thousand ‘eggs’ (primary  oocytes arrested at prophase of meiosis 1)  are present in the ovaries at birth Only ~500 of these eggs (one per month) will  undergo meiosis to form a haploid ovum
Image of page 6
    Oogenesis Germ cell   oogonium (2n)   Primary  oocyte (2n)  (arrested stage present at  birth)    Secondary oocyte + first polar  body (n, first meiotic division)   ovum +  second polar body (n, second meiotic  division Note: spermatogenesis yields 4 haploid  sperm from one germ cell; oogenesis  one haploid ovum and two polar bodies
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
   
Image of page 8
    Sex requires male and female  gametes Dioecious  (two houses) animals have  separate sexes (male & female) Monoecious  (one house) animals have  both testis and ovaries within same  body (hermaphrodites) Hermaphrodites can be either  simultaneous  or  sequential
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
    Sex-changing wrasses She’s the boss What are potential advantages to sex reversal in these fish?
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern