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Spermatogenesis and Oogenesis

Spermatogenesis and Oogenesis. Pgs. 984-985 (Campbell). Spermatogenesis. Production of sperm Continuous and prolific Each ejaculation contains ~100-650 million sperm Occurs in the testes Seminiferous tubules. What happens is ….

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Spermatogenesis and Oogenesis

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  1. Spermatogenesis and Oogenesis Pgs. 984-985 (Campbell)

  2. Spermatogenesis • Production of sperm • Continuous and prolific • Each ejaculation contains ~100-650 million sperm • Occurs in the testes • Seminiferous tubules

  3. What happens is … • Spermatogonia (stem cells that give rise to sperm) are located at the periphery of each seminiferous tubule • Spermatogonia are diploid • Developing sperm move toward the central opening (lumen) of the tubule as they undergo meiosis and differentiation • 4 cells result • Develop into mature sperm • Haploid

  4. Pg. 985 Campbell Page 985 Campbell

  5. The structure of sperm Campbell

  6. Oogenesis • The development of ova • Mature, unfertilized eggs cells • Happens in the ovary • Oogonia (stem cells that give rise to ova) • Multiply and begin meiosis • STOPS at prophase 1 • At this phase, the cells are called primary oocytes • Remain in this phase until the onset of puberty, when they are activated by hormones • Activated by LH and FSH

  7. What happens next ... • Beginning at puberty, FSH periodically stimulates a follicle to grow and induces its primary oocyte to complete meiosis 1 and start meiosis 2 • Meiosis then STOPS again • The secondary oocyte, released during ovulation, does not continue meiosis right away • Penetration of the egg cell by sperm triggers the completion of meiosis • Then meiosis is complete • LH stimulates the completion of meiosis

  8. Campbell Growing follicle

  9. Major difference #1 • 1. unevenness in the mitotic division/cytokinesis of oogenesis • Almost all the cytoplasm  1 daughter cell (secondary oocyte) • 3 polar bodies which degenerate • Spermatogenesis = four mature sperm

  10. Major difference #2 The cells that produce sperm continue to divide by mitosis throughout life (males) Not the case for women *born with all the primary oocytes

  11. Major difference #3 • Oogenesis has long resting periods • Sperm is produced in an uninterrupted sequence

  12. Exit Slip • On the slip of paper, write a proper heading and title it Exit Slip 4/14/09 • Answer the following questions in complete sentences: • 1. When (during the menstrual cycle) does the production of the hormones FSH and LH peak? • 2. Arrange the following organs in the correct sequence for the travel of sperm: epididymis, testis, urethra, vas deferenes • 3. List one function/role for the following hormones: • Testosterone • Estrogen • FSH

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