Pharyngula

Posted by: revere | October 20, 2007 11:15 AM

I guess it's in the eye of the beholder.

Posted by: Moses | October 20, 2007 11:58 AM

I think that this link to footage from the U.S. Congress explains exactly how an eyeball is like an erection.

Nothing better to do that worry about that? No wonder our country is headed down the shitter.

Posted by: Dustin | October 20, 2007 3:21 PM

If you've seen even ONE Tex Avery cartoon, you know the answer.

Priceless.

Posted by: Laser Potato | October 20, 2007 7:04 PM

I dunno, but I know how a Moai statue is like a gun turret.
http://www.youtube.com/watch?v=A1KKLmxrkbs

Posted by: Cuttlefish | October 20, 2007 10:16 PM

http://digitalcuttlefish.blogspot.com/2007/10/at-one-time-or-other-each-sister-and.html

(for some reason, I am being blocked from posting the whole poem.)

Posted by: RamblinDude | October 20, 2007 11:41 PM

Cuttlefish: Evidently the spam filter wants no connection between the eyeball and "erection".

Posted by: Torbjörn Larsson, OM | October 20, 2007 11:49 PM

"display of concentration, and orgasm" - display of concentration, an orgasm

Posted by: Mike from Ottawa | October 21, 2007 12:18 AM

"Revere has inspired me to add a bit about the penis and v*agra to the lecture. Here at UMM, we're all about giving students information they can use."

If the utility you see for your students is in the v*agra aspect, then I think you've not done UMM marketing any good: "UMM: Putting the 'ED' in '.edu'!"

Posted by: Cuttlefish | October 21, 2007 1:50 AM

Hmm...with apologies, then... and please, PZ, delete it if you wish...

At one time or other, each sister and brother
Has pondered the musical question
(The topic's not easy, just take it from PZ):
How an eyeball is like an er*ction.

The answers may vary--be skeptically wary--
Like "Both can display your affection."
Well, so can a rose, but that doesn't disclose
How an eyeball is like an er*ction.

Perhaps evolution provides a solution
Both organs arise through selection
But so, then, do fingers; the question still lingers
How an eyeball is like an er*ction.

We may hope to deduce, if we try to reduce
To a chemical sort of connection
But will "similar stuff" prove an answer enough
How an eyeball is like an er*ction?

Nitric Oxide (you know, you can call it NO)
Causes GuMP to take up a collection
So that GuMP, for a lark, keeps your dick "in the dark"
Thus an eyeball is like an er*ction

Reproductive success got us into this mess
So it might get us out, on reflection--
But V!agra, we find, is not blindly designed
We distinguish both eye and er*ction.

With both vision and hearing, the answers are nearing
(Although we can't hope for perfection),
And for now it's just fine as a bad pick-up line:
How an eyeball is like an er*ction.*

(*answer: "It's an empirical question--let's experiment, and find out.)

Posted by: truth machine | October 21, 2007 7:25 AM

Nothing better to do that worry about that? No wonder our country is headed down the shitter.

Um ...

Posted by: daedalus2u | October 21, 2007 4:21 PM

If you are going to talk about sGC and NO, you have to mention this, one of the most important recent results in NO physiology.

http://www.pnas.org/cgi/content/full/101/1/37

What it does is couple NO and ATP physiology. That lets NO (which is freely diffusible into all tissue compartments) regulate ATP levels in those different tissue compartments so they can go up and down in sync. That lets adjacent cells (as for example in a muscle) have the same ATP level and so the same rate of work production.

If you are going to talk about Sildenafil, you should mention this,

http://archinte.ama-assn.org/cgi/content/full/166/16/1763

that by blocking PDE5, the feedback of the NO regulatory system is affected, and (no doubt) physiological pathways not involving cGMP don't work as well, such as the regulation of breathing via RSNOs

http://www.nature.com/nature/journal/v413/n6852/full/413171a0.html

This relates to my research on basal levels of NO, where because all NO sensors only sense the sum of NO from all sources, a change in the basal level affects all NO mediated pathways with no threshold. That is because NO is already in the "active range", any change in the basal level will affect the output of that feedback regulated pathway.