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Title: Hi! need help about my assigntment Post by: marinoumali on Sep 12, 2010 what are the deformities of the sperm cell and egg cell?
and why why is it that only one egg cell is produced after meosis while 4 sperm cells are produced in the male Title: Re: Hi! need help about my assigntment Post by: bio_man on Sep 12, 2010 why is it that only one egg cell is produced after meosis while 4 sperm cells are produced in the male
In actuality, 3 polar bodies are produced + 1 Mature ovum (gamete) = 4. The polar bodies die off in females, while only the ovum will mature and be released into your fallopian tube about halfway through, but in males, all four sperm survive following the final stages of meiosis. I think the reason is because the meiotic divisions in oogenesis involve unequal cytokinesis, with the smaller cells becoming polar bodies. Evolutionary explanation to why the polar bodies die off is because it takes less work/energy to upkeep a single cell than it does for four cells. In other words, to maintain all four cells is harder for the female body than to produce just one. I will try to get back to the first part later... Title: Re: Hi! need help about my assigntment Post by: bio_man on Sep 12, 2010 Here are some sperm cell abnormalities:
A. Knobbed acrosome (common form) B. Knobbed acrosome (beaded form) C. Pyriform head (severe) D. Pyriform head (moderate) E. Pyriform head (slight) F. Nuclear vacuoles G. Diadem defects H. Detached head I. Distal reflex J. Dag-like defect (broken midpiece) K. Dag-like defect (severely bent midpiece) L. Proximal droplet M. Distal droplet N. Teratoid (severe) O. Teratoid (moderate) P. Normal spermatozoa Oocyte deformities are usually genetic-based (not saying that sperms are not) and so they don't have certain shape abnormalities like sperm cells do. |