h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I was wondering; why do the areas around our eyes go red and swell when we cry for a while?

Increased blood flow to the tear ducts.

B

Thanks.

Is that true? Never heard that before. Do remember there being a different explanation but can't remember what it is.

Well, the other explanation is a bit more prosaic. You rub your eyes more when you cry, thus damaging the skin, thus increasing blood flow to that area but by a different means.

B

in general: any part of your body that turns red is a result of increased blood flow to that part.

**smirks**

B

I was wondering when that reaction would pop up *smirk again*

Oky doky. I suppose the increased blood flow bloats the skin then?

The capillaries in the region will swell and move closer to the skin, yes.

B

why is there increased blood flow anyway?

"Well, the other explanation is a bit more prosaic. You rub your eyes more when you cry, thus damaging the skin, thus increasing blood flow to that area but by a different means."

Erm, how about the ladies who don't want to mess up their make up so refrain from rubbing their eyes no matter how much they cry? No rubbing so no red eyes?

I haven't checked, maybe it's true and your eyes don't go red if you don't rub...?

Lizard King

Oh, I think their eyes will turn red, but it will be the white of their eyes (those little veins), not the eyelids. And even if those turn red as well, you wouldn't notice, because of the make-up.
women don't rub their eyes, in order not to ruin their make-up, they just dab the tears with a handkerchief or something.

there can be a number of causes for increased blod flow:

1. heat: the veins (capillaries) come nearer to the surface, thus providing a cooling effect

2. hormonal: basicly sex. A number of other stuff as well, but minor compared to the attraction between the sexes.

3. nervous stimulation: pain, or embarresment...the neurotransmitters that get released as a result of these stimuli also can cause 'redness'.

Does peeling onions increase blood flow?

well, i guess the chemicals in the onion are irritating for the eye.
But the weird thing is: I can peel onion 'liquid free' when I have my contacts in, but when I'm wearing my glasses, then I start to cry.