Ask MetaFilter questions tagged with physiology

Caffiene snooze

divabat — Wed, 18 Nov 2009 17:58:53 -0800

Why does one cup of coffee make me sleepy? I've seen this thread, but it was more about confirming the effect rather than explaining it.

I've had an interesting history with coffee. I like the taste, and when I was a teenager I regularly had a cup of 3-in-1 coffee a day with no particular effects. In my late teens I was diagnosed with panic disorder, and I could no longer take any coffee without feeling jittery and anxious. Within the past five years I've slowly reintroduced coffee into my life, and now I can comfortably have a cup a day.

However, instead of either getting a buzz or being jittery, coffee makes me really really sleepy. As soon as I have a cup I have a deep need to take a nap, and I can be knocked out for a couple of hours. It's not particularly restful or refreshing sleep, but it's hard to fight back the urge to snooze. This is a recent development (and slightly annoying because there are times where I could use the buzz!!).

I'm usually described as "hyper" by my friends and peers, though that usually depends on the situation - in fun energetic environments I can be very vibrant and exuberant, though when I'm at home I'm usually sloth-like and lazy. I sleep about 7-8 hours a night; the sun awakes me, so I'm usually up just before 5, and for the first few hours (if I'm not having to be awake early for any particular reason) I vacillate between mucking around on my laptop and snoozing. I don't deal well with late nights - if I'm not distracted by something I usually clamour for my bed by midnight at the latest.

Guarana, ginseng, and other energy drinks & supplements of that ilk give me a headache. There is one particular Aussie brand of energy drink (can't recall the name offhand) that hasn't effected me either way; however I've only had a small tin so I don't know if it's a fluke. I have been suspected of having ADD but have never been on treatment for it or tested professionally.

What's happening with my hormones and my brain that makes me have the opposite reaction to caffiene? Is it something I need to worry about? If caffiene makes me tired, what can I do to get a buzz (assuming that I haven't already scared people off by being highly energetic!)?

Nervous and cardiovascular systems detail for high school A&P?

houseofdanie — Wed, 21 Oct 2009 08:26:25 -0800

Hello! I am leading an Anatomy & Physiology study group for homeschooled teens. The aim is to work at the advanced high school level, but I'm using a college textbook (Thibodeau & Patton), as the illustrations and charts are more useful, and it might come in handy for them for later reference. But I'm not sure how deep to delve. Does anyone know the detail with which HS A&P classes generally tackle the nervous and cardiovascular systems? I've found some syllabi online, but nothing with enough information to tell me how deep to go. I, myself, didn't take A&P til college.

Many thanks!

Uh...hang on, just give me a minute.

Demogorgon — Mon, 12 Oct 2009 10:34:31 -0800

What is the most important scientific question of our time? I volunteer at an observatory for a local amateur astronomers' society and one of the guests at a recent star party came up and asked, "What do you think is the most important question science has to answer right now?" Obviously, there is no right or wrong answer, but after the party was over a lot of us were still talking about this question and I ended up learning a great deal from my fellow club members that I might otherwise not have.
The next time this question gets asked I want to be prepared to offer a variety of answers from differing fields and opinions. I don't expect to represent every answer as an expert, but I'd like to be able to give a few more examples than I was able to, and then correlate them to some book recommendations from the answers in this thread about introductions to your field.
I also think it is important to frame the question in a way that can be meaningfully answered, i.e. "What is the most important scientific discovery about to be made?" or something like that.
Of course, I had my own answer in mind, but as a relative layperson to that branch of study I had a really hard time articulating why it was so important to "science." Therefore, if you are uniquely affiliated with a specific field that you think will produce a game-changer, feel free to get as technical as you're comfortable doing.

Thanks!

What Medically, Anatomically Is Happening In This NSFW Skydiving Photograph?

WCityMike — Mon, 03 Aug 2009 08:59:26 -0800

Something that's always had me a bit curious: how is what's happening to the breasts of the female skydivers in this image that's circulated around the 'Net (NSFW) even anatomically possible? I obviously know what's causing this – the force of the air from their freefall – but I suppose I'm just a little stumped on why the physiological result is that.

And why, if there's such a wind force, does there remain extruding "sides" of the breasts? If you were to flip the picture upside down, the effect on their breasts is sort of like a cup – a cylindrical "side" of the cup with a depression formed in the middle. If there's such a wind force as to push a female breast into the shape of that depression in the middle, why do those "sides" still stay up? Wouldn't the whole thing be a depression pushed inward?

(And, as a side note, speaking as a guy, how can that be happening to the female skydivers' breasts without his own, ahem, extrusion suffering from a similar condition?)

I'm not sure if this was originally put on the 'Net to be arousing, but I didn't find it the least bit so – my main reaction to it was a curious "How the hell does that happen to the human body?"

So, those with medical knowhow, mind enlightening me?

Why don't adults enjoy dizziness?

ivanv — Sun, 31 May 2009 10:15:15 -0800

Why don't adults enjoy dizziness like kids do? When I was a kid I remember thinking adults were boring for not enjoying the feeling of dizziness, and I vowed to always enjoy it :) Now as an adult, I can't stand it, and feel like throwing up. It seems most adults (if not all) feel the same way. Why is that?

Catfilter: If I spay my cat while she's in heat, will she continue to yowl for the rest of her life?

bunky — Sun, 22 Mar 2009 15:57:00 -0800

I thought my cat had just _finished_ her first heat and made a vet appointment to have her spayed tomorrow. Well, guess who started yowling and moving her tail sideways to display feline private parts?! Should I keep tomorrow's appointment and have her spayed _during_ her heat, or should I wait? I once knew a (human) female who took the Depo-Provera shot for birth control. Well, they gave her her shot at the wrong time in her cycle and she ended up having her period _all month_. I'm worried about something like this happening with teh cat if I go through with the spaying...and combing the internet for answers, I've seen it written that this can happen. Readers, do you know of this actually happening to a cat you know?

Can anyone recommend a good graduate school for Nutrition Major?

pixxie — Mon, 29 Dec 2008 00:32:43 -0800

Hi, I only have 1 1/2 years till I'm completely done my undergraduate nutrition degree in Canada. I've already established that I want to pursue a masters, however, the only school I have been checking online is Columbia's Department of Nutrition because it is the only school I can think of which offers a decent program. Is it true? If not, does anyone have any good suggestions (NA, Europe, Asia)? Right now, I'm mostly interested in the subject of metabolic disorders. Before telling me your answer, I think it is important to know the pros & cons about me.

Pros:

1] I've been taking a lot of 500-level courses relating to physiology and experimental medicine (e.g. advanced applied cardiovascular physiology and endocrinology)

2] I have been volunteering for a non-governmental organization for quite a long time now

3] GPA is +3.6

Cons:

1] Haven't written my GRE yet (this summer, but I don't know where to begin!)

2] This is my 2nd degree, I did a degree in chemistry before but my GPA was very low (3.12), got some F's that I'm not very proud of :(

3] No research experience because I feel that my degree doesn't really offer any good biological lab techniques compares to someone in physiology or biochemistry let's say. This is definitely my downside. I hope to email some professors this summer who work in the hospital, but why would they hire me instead of a physio major?

4] Haven't taken Genetics

Books on DVDs on exercise as body-exploration?

shivohum — Wed, 02 Jul 2008 16:12:04 -0800

Are there any good DVDs or books that teach you exercise as a way of understanding and having fun with your body? I'm looking for a system whose focus is not primarily on losing weight or being healthy but on learning about your body and being able to do cool things with it you couldn't do before (gain better balance, stand on your head, improve your ability to drag furniture even), but that would also incidentally give you an excellent workout. Ideas?

Let he who be without sine...

phrontist — Sat, 28 Jun 2008 19:00:54 -0800

Why are sine waves considered "pure" tones? Why do we consider sinusoids the building blocks of periodic functions? When analyzing physical, electronic, and acoustic/musical phenomena, it's often handy to view things in the frequency domain. I understand the basic idea of Fourier Analysis, namely breaking apart periodic functions in to the sums of sinusoids of given frequency and phase.

What I don't get is why or how sinusoids are "special". I know in the real world a great number of objects are essentially complicated dampened spring oscillators, so sinusoids are common in nature. Is that the end of it, or is there some deeper reason this function is good at representing periodic phenomena?

Isn't it possible to do a fourier analysis that breaks an arbitrary periodic function in to the sum of any other periodic function? Why not square waves, or a sawtooth?

While sine waves sound "pure" to me, it seems highly subjective. Is there something more than convention at work here? Some property of the ear?

The wikipedia page for sine waves reads...

The human ear can recognize single sine waves because sounds with such a waveform sound "clean" or "clear" to humans; some sounds that approximate a pure sine wave are whistling, a crystal glass set to vibrate by running a wet finger around its rim, and the sound made by a tuning fork.

This seems arbitrary though.

We say that the timbre of a violin is complex because it has many different harmonics. But the very idea of harmonic content assumes some basis function, right? Could we just as easily say a sine wave is complex by choosing square waves as our basis of spectral analysis?

So is this just a convention, and if so, where do we get it?

Does the human brain respond to certain note progressions in music?

slo — Thu, 26 Jun 2008 09:00:31 -0800

Is there a physiological response to certain phrases in music? I read an article a few years ago in the New Yorker that I can't find now. A portion of the article said that there are theories that say people have a physiological response to certain music. In particular it talked about "Ave Maria" and the "Santa, Mariiiiiiia" part toward the end where the vocals jump from a low note to a very high note. The article claimed that this triggers an emotional response in most listeners that is actually because of some common reaction in the human brain.

Does anyone remember this article? Have you read other articles that talk about this response?

Thanks for any help.

When in doubt, it's a "renal" something or a "hepatic" something.

houseofdanie — Tue, 13 May 2008 00:23:07 -0800

On Thursday morning, I'm taking my final exam in Anatomy & Physiology II. I typically have test anxiety, and this time, it's reaching fever pitch. What are your favorite little mnemonics and/or rules of thumb that you rely upon in order to remember... uh, everything? Tho I tend to test well, this particular exam is a pivotal one in my education. I have extensive notes, charts, books, diagrams, and what-not, all of which I've studied til the cows came home, but I find it comforting to have little mental crutches when thinking about complex subjects.

As an example, I adore the "Never Let Monkeys Eat Bananas" mnemonic for remembering the leukocytes and their relative percentages in blood. From this, I can imagine the pictures I've drawn for each cell type, what they do, and so on and so forth.

On this exam will include: endocrine system, reproductive systems, fertilization and development, lymphatic and immune systems, cardiovascular system, respiratory system, digestive system, urinary system, metabolism (redox reactions; anabolism/catabolism of carbs, fats, and proteins), electrolytes in body fluids, and acid-base balance. I think that about covers it. The nervous system was covered in detail last semester, but of course, it permeates every other system, so it's still important to keep in studies.

My weak points are histology (locations of various connective tissues will kill me) and anatomical precision in areas such as cardiovascular layout. I'm strongest with chemistry and general physiology.

Aaaanyway, just as a matter of keeping my panic to a dull buzz, will you please share your mental crutches with me? My future patients and I thank you very much!

THIS IS MY ANGRY FACE

Rhaomi — Sat, 12 Apr 2008 14:37:09 -0800

Are "fast zombies" really plausible? I've watched a few "fast zombie" movies over the last few months -- 28 Days Later and 28 Weeks Later, I Am Legend, etc. I also have a habit of reading up on movies I see afterwards, to find the trivia and background details that help flesh out the storylines. So it was interesting when, in the course of reading various interviews with the filmmakers, I found that they all had the same basic explanations for why their zombies were the way they were.

They're not supernatural or "undead" like in the old movies. They're just regular humans infected with a virus that makes them psychotic. These viruses were also said to leave the victim's adrenal glands open all the time, making them super-strong, ultra-fast, and impervious to pain.

I was also intrigued by this article from Cracked (an outstanding scientific resource, I know) which discussed this concept. At one point they assert, "you are just one brain chemical (serotonin) away from turning into a mindless killing machine" and link to a study showing the effects of serotonin depression in rats.

This all seemed a little fantastical to me, a doomsday scenario made to sound way too easy. It made me think of the ridiculous way radiation was used in comics a few decades back. In the Marvel Universe, gamma rays give you invisibility and the ability to fly. In the real world, it gives you leukemia. Surely the same must be true for the zombie thing. Of course, all the googling I did lead to a bunch of unrelated medical papers.

So I'm wondering: are these ideas plausible? What would be the effects of a constant adrenaline high on the human body? Would it really turn you into a hyperventilating superhuman, or just wreck your nervous system?

And what about that serotonin thing? Could the lack of one brain chemical really turn a person into a murderous psychopath? Or would it cause something much more mundane, like depression or schizophrenia or dissociation?

Lastly, what are the odds of any of these chemical changes being effected by a contagious virus (or a bacterium or injection, for that matter)? Could Rage or KV be created in the real world?

How does hair know how long to grow?

slavlin — Thu, 10 Jan 2008 20:16:52 -0800

How does hair know how long to grow? What is it that lets hair on your head (if you are lucky enough to have it) keep growing while the hair on your body stops growing at a certain length?

I'm bleeding from my hands. So why can't I hear?

eritain — Sat, 12 May 2007 07:08:58 -0800

Hypotension/hypovolemia as a low-pass filter: I got cut, I went into shock, and then everything started sounding funny. I'd guess it was a 40 dB (±10) rolloff, which began near 200 Hz (±50) and left me with nothing above 1kHz. How in the world? Story, discussion of numeric estimates, off-the-cuff physiological speculations, etc... About a week ago I had a gentlemanly disagreement with a pane of glass, which left venous blood running richly from two of my knuckles. (No winner was declared, but you should see the other guy. I totally took him.) At the first-aid station, I dropped into a typical case of shock: pallor, weakness, sweating, and thirst. I knew what it was, so I got my head between my knees and asked a bystander for water to sip. I was still feeling awful when someone got a car to drive me and my now-bandaged hands to the emergency room (where those hands would get six stitches and some iodine).

As I walked some 15 or 20 feet to the car, I experienced an unfamiliar symptom: My hearing drained out. First the high end, then the mids went very quiet. A waterfall fountain became inaudible; male voices had a very flat timbre. I could hear the bass rumble of the car engine very clearly, but not its rattling-type noises, or much road hiss/tire noise.

Note that I am pretty bad at estimating loudness, but it was a profound loss. Frequency, I'm a little better with. I understood people speaking, so I must have had some hearing up to 1000 Hz (to make out the first two vowel formants). But 700 Hz is a good estimate for the top of the road hiss that I wasn't hearing, and the loudest sounds were definitely 100-160 Hz or so.

Qualitatively, here is how much shock I was in: My vision was washed out, but not tunneled. My lips, I'm told, were colorless. I did walk 20 feet, but I'm sure I couldn't have gone 40. I had the presence of mind to keep my knees slightly bent in case I went down, and to be irritated at the people who thought that holding my elbow was really gonna help if I fainted. (Arms go limp, yo?) I did not have the presence of mind to say, 'Hold me at the shoulder, not the elbow,' or better yet, 'Wait, give me a minute here, I can't walk yet.' In the car, with a few minutes' rest and some water sipped, the normal shock symptoms receded, and the hearing loss with them.

So: What was that? Has this happened to other people? Can you propose a mechanism? (Could shock drain fluid from your cochlea, or do some fibers of the auditory nerve have a better blood supply than others, or would it more likely be the auditory cortex going under?) I welcome hypotheses, but I'm not about to go gouge myself again to test them. (Hmm, guineapigs.metafilter.com is still available.)

Birds that burble, cluck and coo.

Listener — Tue, 01 May 2007 21:01:39 -0800

What is the physiology of bird sounds? I notice the quails make a sound like a cluck, but it is really more of a burble. In fact it sounds exactly like my fridge, which I think is circulating some water that results from the frost-free mechanism, but now it's driving me nuts: what is the physiology of quail clucks? It's different from how chickens cluck and also from doves coo. It's too much to hope for a bird AND fridge expert in one, but how about some bird experts?

The Underwater Shiver-- What Causes It?

dmaterialized — Mon, 05 Feb 2007 08:26:54 -0800

So I'm still trying to pinpoint this one (I keep forgetting to ask it, and Google turns up nothing)-- when one lies down in a bathtub, faceup, and submerges at least their entire ears, they shiver (it's more kind of an uncontrollable, brief spasm of the upper body and doesn't FEEL like shivering, but looks like it). It isn't related to the water temperature, as far as I can tell, and DOESN'T happen when facedown or swimming, etc. Or do other people not have this happen? Do you? I get it every single time, without fail, and have since I can remember. My mom knows exactly what I'm talking about, but my dad insists we're both crazy. Is this just one of those odd reflex reactions like coughing when you have something in your ear or sneezing when you get in the sun? (I also do that one-- always funny to explain to people :) ) Any idea what causes this, though?

Quick: answer my question. HONK! Sorry. Too slow. You lose!

grumblebee — Wed, 23 Aug 2006 18:38:12 -0800

Why are there fast people and slow people? Why do different people have different paces? I'm a fast person. I do everything fast. I talk fast; I walk fast; I think fast. I get easily impatient with anyone slow (moving or witted). Why?

I'm in fairly good shape, and I work out. But I didn't used to. I used to be a "couch potato" and my diet was horrible. I've never been athletic. I prefer reading to physical activity. Still, I'm fast and I've always been fast. Changes in my age (I'm 40) and lifestyle don't seem to matter.

When I learn a new idea, I don't need time to process it. I'm immediately using it and putting it through all sorts of permutations. I almost never need a break to rest my brain.

In case anyone thinks I'm feeding my ego here, I'm not. I don't think fast = better. I don't think it = worse, either. There are good and bad aspects to it. Yes, I think fast, and that can make me SEEM smart. But it also means I miss things and make mistakes because I'm zooming through life. I am horrible at just "being" (I'm un-Zen), and I get bored easily.

There seems to be a genetic component to this. My grandmother was fast like me. Way up into her 80s she was zooming ahead of everyone on the street and not suffering fools gladly. (Usually the "fools" were just people who couldn't come up with an immediate answer to her questions. If someone needed a fraction of a second to think, he was an "idiot.")

Why am I like this? Why are other people not like this? Why are there so many different people with so many different paces? It it "metabolism"? It it just upbringing? Is it ADD vs. non-ADD? Some combination of these things? Has anyone ever studied this? Books? Essays? Websites?

Pins and Needles: Why?

scrump — Fri, 30 Jun 2006 20:21:25 -0800

What is the underlying physiological cause for paresthesia (tingling of the fingers) secondary to hyperventilation? Specifically, what metabolic or neurological process causes you to feel tingling in your fingers when you hyperventilate?

Is stuttering more common in some languages than others?

IndigoJones — Fri, 10 Jun 2005 04:25:20 -0800

Is stuttering more common in some languages than in others? If singing is supposed to suppress it (true?), does that mean tonal languages (e.g. Chinese) do not suffer the phenom? Indeed, are there any languages in which it does not appear at all? If so, any theories why?

physiology of sighing

stupidsexyFlanders — Fri, 15 Apr 2005 05:28:02 -0800

What's the connection between a thought of regret, or of resignation to a negative situation, that causes humans to involuntarily fill their lungs and exhale slowly? Is such sighing learned behavior? Does every culture sigh for this reason? Animals sigh. When my dog sighs, is she laying there regretting she didn't roll in that dead skunk when she had the chance?

Why is my butt cold?

macadamiaranch — Sat, 26 Mar 2005 15:48:45 -0800

Why is my butt cold? While spooning with my husband, he once again remarked that my butt was cold. But when spooning my husband his ass matched the hotness of the rest of his body. Asking my girlfriends revealed that they have also had partners mention their frosty posteriors.

So what's the deal? I theorized -- and it's a long shot theory here -- that women's butts are cooler so that when spooning with their male companions the cold butt helps keep the male genitals cooler (and thus improving sperm count). But that's probably not it. Is it a fat distribution thing? A circulation thing? Please, AskMe, why are women's butts cold?

Does Whatever a Spider Can

kenaman — Sat, 26 Jun 2004 18:49:22 -0800

Should not Spiderman's web not shoot out his arse?