They can smell blood from how far away, and I can't even open my nostrils.
2007-02-13 17:21:24 · 7 answers · asked by nindash 1 in Science & Mathematics ➔ Zoology
I bet you can't breath under water either, but guess what.....sharks can!
2007-02-13 20:53:03 · answer #1 · answered by Motti _Shish 6 · 1⤊ 0⤋
Great question. I once answered a similar one, so you can check that out at http://answers.yahoo.com/question/index;_ylt=ApG3_IgP8SBN5Q1fFrE1SVvsy6IX?qid=20060813055653AAIEQ9e&show=7#profile-info-07a647b6a4d7e292eacb07b50a5536b1aa.
But let me say one more thing here:
Smelling is per se mediated by so-called chemoreceptors in the olfactory epithelium of your nose. The process is basically the same as for tasting, namely the binding of a ligand (the compound you smell) to the receptor molecule on the surface of the receptor cell. The binding will cause a conformational change of the receptor molecule, which in turn instigates a signal transduction process (basically the influx of calcium ions into the cell, which causes the stimulation of transmitter release). The main difference between smelling and tasting is that in the case of the former the compound to be smelled has to go from being an aerosol into solution of the nasal mucus. Specialized glands below the epithelium (Bowman glands) produce the mucus in which the aerosol is then dissolved. From then on the compound to be smelled (the ligand) can actually reach and bind to the receptor.
Sharks have it a little easier. They get around the problem of having to dissolve anything, because the shape of their nostrils directs the waterflow directly over the olfactory epithelium, thus carrying the ligand to the receptor cells.
Now, you made a really good point there, namely that you can’t (or better, won’t) open your nostrils underwater. Actually you have your nostrils open when you are in the water, but the water does not reach your olfactory epithelium. If it did, you’d most likely also swallow a great deal of water… And that wouldn’t be good. Although, if you did, you’d also get an idea of how things smell. You’d also taste it…
2007-02-15 08:01:14 · answer #2 · answered by oputz 4 · 0⤊ 0⤋
They can small underwater because they don't breathe air, they (essentially) breathe water otherwise it's the same system as what our noses do. Receptors in the nose pick out certain chemicals and you get a 'smell' reaction in your brain.
The only difference with sharks is they pick out chemicals in the water rather than the air.
And they're very sensitive to the chemicals in blood, eg haemoglobin. So they can smell a very small amount in a lot of water: therefore from very far away as the blood diffuses.
Comparing you not being able to smell underwater is like saying sharks could breathe air.
2007-02-13 17:31:35 · answer #3 · answered by Cara 2 · 0⤊ 0⤋
I'm no expert, but sharks have these pores in their snout that are filled with this jelly stuff that reacts to different sensory input. Nobody knows exactly how it works, but everyone is pretty sure this is what makes their smell underwater so acute.
2007-02-13 17:32:10 · answer #4 · answered by Anonymous · 0⤊ 1⤋
I assume the blood will dilute in the water, and the shark gets a hint of it, and traces the source
2007-02-13 17:24:53 · answer #5 · answered by J 3 · 0⤊ 0⤋
They can smell the same way humans can smell- by having molecules of blood hit their olfactory receptors.
2007-02-13 17:30:33 · answer #6 · answered by Young,risky,& looking 4 returns 2 · 0⤊ 0⤋
sorry buddy, i dont know that one....
well, how do ya know they can smell? were you one of them!ha...kidding
2007-02-13 17:28:14 · answer #7 · answered by Anonymous · 0⤊ 0⤋