Bulgy Veins- What's the Deal?

[Theophrastus]

Anyhow, I've been stimulated by personal physical experience, to ask, as is already pre- suggested by the title, why do bulging veins occur? In that, I don't mean it in the sense of being able to see the veins clearly, due to lack of skin pigmentation, but rather that the contours of the veins quite literally bulge, so as to make themselves visible, below the skin.

As well as asking the question of why this occurs, another interesting observation that I've consecutively made, which may also be open to debate, is that this seems to be a particularly prominent thing for people of Slavic origins. (Russia, Ukraine, Belarus, etc.) (Though this "statistic is one that as any, one cannot be sure of, as it is tainted by personal experience) So to conclude on a rather repetitive note: what's the deal?

[Mokele]

Some of it is likely due to blood volume in the veins, particularly when a given body part is below the level of the heart (causing blood to accumulate there).

 

However, a major factor is just the level of sub-cutaneous fat. We all have veins under our skins, but often they're submerged in fat, so the bulge isn't noticable.

[CaptainPanic]

Yep: in your hands, there is hardly any fat, and veins are clearly visible.

On the arms, just a few centimeters away, there is more fat (and muscle), and the veins are less visible.

[Theophrastus]

Yeah, I'm sorry I didn't articulate, I was in fact particularly refering to bulging veins in the distal ends of the extremities. And I definitely agree with what Mokele said in regards to blood volume. I also realised that in terms of what I seemed to vaguely remember about heat, was that bloood vessels closer to the skin, dilate when it is hot, so as to regulate the body temperature, in response to environmental conditions. I was thinking on a similar basis that my trend is simply because of paler skin, of Europeans in the region, which contains less defensive (against the sun) melanin, thus meaning more absorbsion of heat through radiation, or is this difference, really significant enough to induce the effects described, or at least play a fairly significant role? I'm also interested though, in whether blood pressure may have anything to do with it, as one of my friends IIRC, made a comment in regards to it, when I told him of this- Any thoughts?

Edited July 10, 2009 by Theophrastus
insertion of the word "also"

[Mokele]

Diastolic blood pressure (the second, smaller number) would influence the distention of veins, yes.