The Scrotum – Home Of Your Balls

June 6, 2011

I promised to avoid anatomical detail, but at this point I need to summarize some basics. Here goes:

The scrotum is a pouch of skin containing the testicles. Each testicle and its spermatic cord (leading upward into the abdominal cavity) is nested in its own compartment within the sack. Part of the spermatic cords are the vas deferens – as we know thin tubes through which the sperm travel. The spermatic cord also contains blood vessels, nerves, and muscles.

In response to certain stimuli and/or temperature changes, these (cord-) muscles contract and pull the testicles closer to the abdomen. Generally, the subskin-muscles of the scrotum will contract as well by the same triggers. In a way the scrotum acts like a thermostat, trying to provide an even temperature for the continuous and optimal sperm-production and storage within the testicles. This temperature has to be slightly lower (at 34 degrees Celsius) than that of the rest of the body.

Although both testicles are of about the same size, the left one usually hangs a little lower and thus may give the appearance of being larger. The testicles serve a double function: a) they produce sperm, and b) they produce hormones which are secreted directly into the bloodstream.

The reason why the balls are drawn up close to the body (sometimes into the abdominal cavity) via a tight scrotum lies in the fact that our body temperature is increasing the chances for a successful insemination: sperm thrive at body temperature for 50 minutes to four hours, the average length of time it takes for them to journey through the female reproductive tract and to fertilize the egg. So just before ejaculation, when it’s adaptive for sperm to be highly mobile and hyperactive (from an evolutionary point of view), the scrotal muscles (cremaster and dartos) reflexively retract to provide a raised ambient temperature for sperm. Anytime else sperm are stored and produced most efficiently in the more breezy surroundings of the rather relaxed nut-bag.

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