Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Donnah on 30/05/2003 00:36:05
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I've heard that tears of sadness[:(] and tears of joy[^] differ slightly in their chemistry. What are the similarities and differences?
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One way to mix sadness and joy...
"make your wife cry whilst you are having sex...by ringing her up and telling her !"
Pat
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LOL!!!!!!!!!!! pat's a genius!
Resident Tour Operator - The Naked Scientists
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oooooh ... kaaaay .... [xx(]
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Cry do we cry? Does anyone know? We produce tears to protect our eyes but why cry when emotion? No protection is needed.
Tom
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Tom, we need to cry sometimes as a bodily function. Men have tears and tear ducts the same as women and they feel emotions, so why is it less socially acceptable for men to cry? That doesn't make sense. It's like deciding that it's unacceptable for one gender to urinate. You can drink less water, and try to hold it back, but sooner or later the body demands its own release.
quote:
Originally posted by pat
One way to mix sadness and joy...
"make your wife cry whilst you are having sex...by ringing her up and telling her !"
Pat
Pat, if the wife doesn't answer maybe it's because she (unlike her husband) doesn't do phone calls during sex. Has anyone seen the milkman lately?
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I think it is socially unacceptable because men are supposed to be strong, and it is weak to display your emotions. Crying is displaying one's emotions.
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Donnah that's not what I meant.
We have tear duct to protect our eyes say if cold wind blows in your eyes. I got this from my teacher, tears have antibotics to clean our eyes.
Crying is perfectly normal, but why when we feel emotional? If nothing is bothering our eyes then why do we cry?
Tom
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Is it not histamine we have in our tears rather than antibiotics...
Resident Tour Operator - The Naked Scientists
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Quite a puzzling conundrum.
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Mmm... I've confused myself now.
Tom
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I'm no medic, chris is probably the best person to ask... but i'm pretty sure the body releases histamine as a natural defence against foreign bodies, it can release too much which for example with pollen, results in you having an itchy eye. The tablets you take are antihistamine which reduce the levels of histamine and thus the itchiness. I THINK...
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Right, better clear this up I suppose.
Tears have a number of functions, including protection, immunity, lubrication and cleansing.
They are produced by the lacrimal gland which sits at the upper outer edge of the eye and secretes tears in response to various stimuli, including emotion and irritation to the eye. Tears drain away via the lacrimal ducts. You can see these on yourself if you look in the mirror at the eyelids close to your nose. On each is a small dark 'dot' (the punctum) which is where the tears drain away. The lacrimal duct opens into your nose which is why sneezing can make your eyes run (because the tears all get blown back up into your eye), and blowing your nose is suggested by some as a good way to dislodge foreign bodies (dirt, grit, eyelashes) from your eye.
Tears are made from the secretions of cells lining the ducts of the lacrimal gland and are composed of water containing dissolved salts and proteins which include mucin, antibodies and lysozymes.
The role of mucin is in lubrication so that the eye can move freely. It is also present in saliva where it helps food to slip down easily. The antibodies, which are IgA, are there to mop up and neutralise pathogens, whilst lysozyme is an enzyme which can break down bacterial components, hindering the growth of bugs.
Histamine is not released in tears but by tissue-resident mast cells which store histamine in granules inside the cell, together with other inflammatory substances. Mast cells are rather like those spiky mines you see floating around in the sea in old war films. The spikes are IgE antibodies which are supposed to lock on to components of pathogens and cause the mast cell to 'go off', discharging the contents of its granules. Histamine release causes blood vessels to dilate and become leaky, in theory to help immune cells reach the area quickly so that they can rapidly neutralise any invaders. In an allergic person the IgE levels are much higher than normal and the IgE antibodies recognise things, like pollen, which are ignored by the IgE in non-allergic people.
Histamine unleashes its inflammatory effects by binding onto receptors on the surfaces of cells. Rather like a key going in to a lock histamine fits nicely into these receptors which then relay a message to the cell to switch on its inflammatory machinery. Anti-histamines work by erecting a barricade in front of each of the receptors so that the histamine cannot get through, blocking its effects. Often this is achieved by making a molecule which, in some ways, looks very similar to histamine, but is chemically different; in other words it is like inserting the wrong key into the lock. The key goes in, but won't turn. But, all of the time that the wrong key (an antihistamine) is in the keyhole, the right key (histamine) can't be inserted, so the 'inflammatory doorway' stays firmly shut.
Obviously this is a massive simplification of the process. Ligands like histamine, and drugs like antihistamines, usually lock on to the receptor, and then detach again a short time later, then lock on again, and then detach again, creating a window of opportunity for histamine to quickly sneak in and activate the receptor in the split second when the drug has disengaged. This is why you can still get allergic symptoms, even with antihistamines on board. The drug molecules just cut down the chances of the histamine molecule binding to its receptors by being present in greater numbers than the histamine molecules. But as soon as you increase the number of histamines (by exposure to more allergens) the score evens up until eventually the histamine outnumbers the drug and wins.
An old chemistry teacher put it very nicely for me once which helped me to understand the whole process. In this instance we were talking about osygen therapy for carbon monoxide poisoning, but the principle is the same. He said "if I threw a lamb chop into a pit containing 99 poodles and 1 bulldog there is a very high chance that the poodles would get the chop off the bulldog. But if I threw a chop into a pit with 99 bulldogs and 1 poodle then the odds of a poodle getting the meat are pretty slim !"
If you substitute histamine for bulldog and antihistamine for poodle, you'll understand the concept.
Chris
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
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Thanks Chris, you know a lot. (https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fsmilies.crowd9.com%2Fcontrib%2Fcorky%2Fcorkysm60.gif&hash=f6260822491b023e0289b810e446d897) Obviously you're a doctor.
Tom
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So, since babaies can't talk they need some other way to signal to their carers what they need. However it evolved -probably because tears for cleansing were there already to be used -babies cry to get that attention. We cry less and less as we grow older and are better able to express ourselves verbally, but it is still a physiological response that exists within us and can be re-awakened at moments of stress -that's supposedly why we cry out of negative emotions. But I wonder why there are some people who cry from happiness? If the baby development thing holds true for happiness, shouldn't we just gurgle and drool instead? I suppose babies also tell their caretakers that they are satisfied by smiling and giggling, which is mainly what we do as adults as well.
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Good point there.
Tom
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I gurgle and drool when I'm happy.
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I believe you[:D].
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But isn't it strange how a smile that shows positive feelings in a human corresponds to the baring of the teeth in an animal, where it shows negative feelings? What is your explanation for that chris? No doubt you have one !
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Interesting. I believe that it's a case of having certain muscles doing certain things. Different species, different muscles for different functions. We have opposable thumbs and smiling (elation) muscles. They have tails and "grrrr" (negative) muscles.
Just a thought.
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There are some dogs who smile. It's unusual, interesting, and sometimes difficult to differentiate from a simple baring of teeth unless you know the dog well. I've worked with large numbers of animals and owned a horse who smiled and would kiss me on the cheek, but only when no one was looking. One day someone came around the corner just in time to see Blaze kissing me, and after that he never did it again. He was an astonishingly intelligent horse and I still miss him.
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Interesting point about smiling animals. Our dog 'smiles' - bares all his teeth when he sees us, and a friend has a dog that does the same thing. I'm not sure that dogs can associate our teeth as being anaologous to their teeth and hence they can't be 'copying' us in smiling. But they certainly respond to eye contact don't they. One of our dogs will only maintain eye contact for a short while before becoming very self-conscious and trying to hide his face. Similarly a good way to guard against attacks by tigers is to wear a mask on the back of your head since this fools them into thinking that you can see them trying to creep up on you from behind. Hence animals do seem to have a concept of eye contact... What do you think ?
Chris
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
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Horses generaly bear their teeth against the wind. It feels good to them. A vetarinarian(sp) Told me that they can't breathe through their mouths, so they take in air through their teeth because it feels good. We had a champion race horse when I was working a ranch that was killed by some competitor's trainers by putting ping-pong balls in it's nose. Sad.
It gives me the creeps to see a dog "smile". It would also give me the creeps if I saw someone with a mask on the back of their head. I think that would detere more than just tigers. Interesting tid-bit.
Once at the zoo, my buddy (who is very tall) was leaning forward with arms apart on a railing. He was laughing at the gorillas. His girlfriend was reading the plaque about how they "bow out" their arms and bare their teeth as a sign of aggression. At that moment, the gorilla saw my friend, (bowed against the railing and baring teeth)and almost came through the glass barrier at us. I screamed like a little girl. Maybe I should wear a mask on my next trip to the zoo.
Just a thought.
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Chris,
I think about the eye contact thing is quite essential.
For example cats, if you made hard and long direct eye contact wiht them, usually they see it as a threat if you are a complete stranger.
In the area where we used to live, there are many cats and at the begining when I saw one, I made eye contact with him and the cat started to hiss and snare at me. About 2 or 3 years later I found that cats don't make eye contact with each other if they are to show a friendly sign. They sort of blink, turn their heads and ...it's hard to describe.
Tom
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Chris, you're lucky to have a smiling dog, I find it quite endearing in an animal. What type of dog is it?
Dogs try to hump people's legs not as a sexual action (sorry Ronnie), but as a sign of dominance. Animals communicate in various ways and eye contact is frequently viewed as a sign of aggression. Especially with gorillas. When a gorilla looks at you you should drop your eyes to the ground. Not to do so at a zoo is to torment the animal. I saw a gorilla being teased by an ill-behaved girl, but the gorilla got the upper hand when he turned and pressed his butt against the glass right where her cheeky little face was.
Horses see "independently" out of each eye, so before riding a horse that doesn't know me, I talk to him/her quietly, stroking the neck on one side and then move to the other side and do the same thing. I also breathe through my nose close to the horse's nose and the horse usually does the same thing back. They are a more relaxed mount after that.
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It's interesting that animals recognise that eye contact with a person is analogous to eye contact with one of their own kind. In other words, animals know what eyes are and do ?!
More interesting is the issue of self-recognition or "self-consciousness". Psychologists have long-delighted in sitting babies of different ages in front of mirrors and then painting a big red mark on their heads. Initially they do not realise that the mark is on them but assume that the baby in the glass is another baby unrelated to them.
Dogs likewise do not seem to recognise themselves. The can recognise the image of a dog, but they do not identify their reflection as their own.
To my knowledge only higher apes seem to share our ability to recognise ourselves in a mirror. I'm not sure about marine creatures like dolphins though...interesting question. Anyone know ?
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
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It's interesting to explore the differences and the similarities between humans and animals. I've known many people that avoid eye contact and animals that look you right in the eye. I've always wondered about the dog humping thing. When I hump someones leg it has nothing to do with dominance.[:)] Why would a dog hump an inanimate object, such as a pillow or a teddy bear?
My son was born with a "strawberry hemosomething" on his forehead. It looked like a cherry on top of his head. It went away after he was 2 and when he saw a picture of himself with it, he asked who that baby was. He freaked out when he realized it was him and wondered why he didn't have it anymore. Now, he has made reference to when he was a baby in a way that almost sounds like he was another child. I wonder if that had anything to do with his strawberry. I've never heard of the red paint experiments, but venture to say that Ian's response to his strawberry may be a related issue.
Just a thought.
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To quote Donnah and totally take it out of conext..."I talk to him/her quietly, stroking the neck on one side and then move to the other side and do the same thing. I also breathe through my nose close to the horse's nose and the horse usually does the same thing back. They are a more relaxed mount after that."
I wonder if this would work in dating? [:p]
Just a thought.
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You intend to date a horse ? People go to prison for that sort of thing. That said, many man would say they already do.
Pat
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OOPS. I meant to delete the horse part from that. hahaha
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Good one Pat!
I've heard many a man bragging that they are...like a horse. I think it has the opposite effect to what they are hoping for; rather than mounting, I walk....away.
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Back to the tears issue with a question for Chris. Since tears have antibiotic in them, can you ever culture bacteria or viruses in tears? And when you get conjunctivitis, is that bacterial or viral? And if so, then why don't your tears cure the problem? Do the lacrimal glands ever get infections such that the tears themselves actually become contaminated?
Bezoar
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That's a good point. Our bodies' immune system, well lymphocytes memorise the antigen of foreign bodies. If we get things like conjunctivitis why don't our tears produce antibodies to fight off the bacteria/virus if we got it before?
Tom
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Cry do we cry? Does anyone know? We produce tears to protect our eyes but why cry when emotion? No protection is needed.
Tom
Maybe to protect our heart (feeling)?
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I think that tears of sadness will contain more sad associated neurotransmitters than these of joy. But still my hypothesis.