Sunday, April 24, 2011

Objectives 71 & 72: How spermatazoa move and evolutionary fitness

Exploring how spermatazoa move through the female reproductive tract and evaluating fertilization in terms of evolutionary fitness......


Well, I guess in a way, sperm are pretty incredible.  When you look at the resistance that they have to overcome in order to achieve their "goal" and the way that they're structured in order to make that happen ...overall, pretty amazing.  Lets take a head to toe look at the structure of the sperm.  At the head, we find the nucleus which encloses the most densely packed dna found in any of the eukaryote cells.  More interesting is that the head is enclosed in an acrosome that contains enzymes that will help it to break down the egg when or if it ever reaches one.  Another interesting fact regarding this is that the acrosome is actually alkaline in nature, so the acidity of the vagina is yet another hurdle that it must overcome.  However, it does have glycoproteins on that acrosome that all immune systems recognize allowing it to enter and find its way through the body without being attacked.


The term spermatzoan actually only applies to a sperm that is mobile.  A large part of that mobility stems from the midpiece of the sperm just below the head that is actually surrounded by ATP to provide energy for movement.  And finally the tail, which I kind of relate to one of those super small 15 horsepower motors on a john-boat, it works and it spins, but it sure itsn't gonna get you anywhere fast!

So it really is amazing that the sperm even makes it to the egg in order to fertilize it.  The fact that it does relates to evolutionary fitness to me.  It will be the strongest, the fastest, the "smartest" sperm that reaches the egg.  The rest simply die.  In my mind this is reflective of evolution itself.  Only the strong survive.

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