Originally Posted by penismith
Are the collagen bands selectively cut in places with new subunits added to fill the slack during puberty?
I doubt it. As I understand it, the tunica remodels itself continually though a process of collagen breakdown and collagen deposition. Deposition might speed up during puberty. As for the part about cutting the bands, see below.
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I am most interested in the bands that wrap around the penis. Where are the anchored and where do the bands end? What fraction of the penis do the bands wrap around or do any? What is the range of band lengths.
I’ve puzzled over this as well. We know that the inner layer of the tunica has circumferential collagen fibers. A matrix of these fibers completely encircles both CCs as a pair (or each CC separately, if you want to consider the septum to be the intersection of the two “tunicas”). The circumferential layer extends the entire length of the CCs—from the glans past where the crus separate and all the way to the pubic ramii.
The fibers that form this layer don’t anchor to anything except themselves. They essentially form a tube. Trabeculae are formed on the inside of the tube and fill in the internal structure of the CCs. At one end the “tube” inserts into the pubic ramii; at the other end, it closes on itself to form the tip of the CC.
I doubt that individual collagen fibers actually form closed circles around the CCs, if that’s what you’re thinking. More likely, the fibers are relatively short and bond to one other laterally via cross links. So, although the fibers “run” around the circumference of the CCs, I believe that no fiber forms a complete circle (or spiral). It’s a matrix of relatively short fibers, linked together laterally, and oriented mostly in the same direction (circumferentially).
With this structure in mind, it may be easier to see that fibroblasts interspersed among the fibers could deposit new collagen fibers that insert themselves into the existing matrix, just as old collagen is being removed. If more material is laid down than taken away, the layer grows in all dimensions—length, width, and thickness.
It probably doesn’t happen this simply. The DNA has a blueprint and the cells “try” to make sure it’s followed, however that happens.
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I don’t think it is likely that it stretches during puberty in the same way as it stretches when we do PE, unless it thickens considerably or changes structure drastically at the end of puberty.
I don’t know. But is sounds like an interesting research project.
Hey, aren’t you supposed to be studying :) ??