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All Posts in Category: Anatomical things you are too embarrassed to ask!

The Mystery of the Itch

One might thing that is over the top and not so important but the science behind the itching was always flimsy. The medicine did not really know why we itch and what the neurological basis behind the mundane itch was.
And it’s not over the top at all: chronic itch caused by dry skin, psoriasis, diabetes or even liver disease can be enraging, and the cause has long been a true medical mystery. There is even an Institute designed exclusively to study the All Mighty Itch – called the “Center for the Study of Itch (CSI)”, from Washington University School of Medicine, in St.Louis, Missouri, whose mission is “to increase our understanding of the fundamental underlying mechanisms of itch and translate these findings into treatments for patients suffering from chronic itch.”
Initially, the theory was that a single class of nerve cells detected both itch and pain. According to this theory, the type and intensity of the stimulus told the cells which sensory message to send up to the brain. The nervous system would then respond accordingly. At one level, the theory is correct: pain and itch, as well as heat, are all transmitted by a class of nerve cells known as TRPV1-expressing neurons. When scientists use genetic engineering to create mice that don’t have these cells, the animals don’t feel any of those three sensations.

When we itch, our initial reaction is to scratch it with our fingernails. This is because the pain of scratching helps to override the sensation of an itch. However, this can also create a vicious cycle, as eventually the pain of scratching is blocked out by serotonin in the brain. Without the pain as a distraction, we then feel the itch again. And so the cycle repeats. The best way to avoid this cycle from beginning is to avoid scratching in the first place, and instead, give an itch with no external source a little slap or rub.
But although pain can block out itch, some painkillers – such as morphine – can cause itchiness. And some things that cause itch also cause pain, such as capsaicin, the ingredient that makes chili peppers hot.
Scientists now have several theories about this odd connection between pain and itch. One theory suggests the same set of neurons produce an itch when activated slightly, but result in pain when activated fully. Alternatively, different cells might trigger pain and itch signals, but the signals might interact in the spinal cord. There is some evidence for both ideas.
But over the past 5-6 years new researched emerged.
The molecular geneticists Santosh Mishra and Mark Hoon of the National Institute of Dental and Craniofacial Research in Bethesda, Md., reported they had found specialized neurons that produce a chemical, called Nppb, that sets off the body’s itch response. Mice that were genetically altered to lack Nppb or in which the receptor for the chemical was damaged were resistant to itch-inducing chemicals — but still sensed pain and heat.
According to Hoon, identifying the neurons that act as “specialized gatekeepers” for this system may eventually lead to drugs that offer relief for people suffering from psoriasis, eczema and other difficult-to-treat forms of chronic itch. In this way, the riddle of the itch will have moved closer still toward being solved at last.

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Men on the Pill?

Whether it’s an IUD, an implant, a shot or a daily pill, birth control is a regular part of many adult women’s lives. It has left a lot of women asking: Why not men? Why are they spared?

Well, it’s not simple. Let’s take a look.

With all the abundance of choices women have in the contraceptive realm, men, on the other hand, have only two choices:

  • condoms – a barrier form of contraception that stops sperm reaching and fertilizing an egg
  • vasectomy – a minor surgical procedure that stops sperm being ejaculated from the penis during sex (it is usually permanent). We don’t want this usually!

For years, scientist have tried to create other alternative birth control methods for men, realizing that this is an untapped market.

There are two directions that this research went:

Hormonal contraception

The World Health Organization commissioned a few years ago what sounded like a promising trial, a two-hormone injection designed to temporarily stop the development of healthy sperm. Initial results looked like it would be 96 percent effective in preventing pregnancy in the participants’ partners. (The effectiveness rate for women’s birth control pill is 99%). But the Stage II trial was stopped after an independent review panel found that the drug had too many side effects. The most common side effect was acne, and sometimes it was pretty severe. Some men also developed mood swings and in some cases those mood swings got pretty bad. One man developed severe depression, and another tried to commit suicide.

I can already see eye rolling from women at this point knowing that women have been experiencing things like mood swings and weight gain for decades with hormonal birth control pills without complaints! But when we do it we go all the way and we don’t take side effects lightly! We are big babies after all, aren’t we?

The other reason this trial was stopped is that even though it seemed a very sound theoretical approach with very good results in the beginning some men, despite all this, still carried on producing enough sperm to cause a pregnancy! Cause: unknown! Aren’t we stubborn sometimes? Yes, we are!

Non-hormonal contraception

One very promising avenue of research is a technique called reversible inhibition of sperm under guidance (RISUG). During this technique, a non-toxic synthetic chemical, a polymer called VASALGEL is injected into the vas deferens.  This is the tube that sperm pass through on their way to the penis. This tube is cut during a vasectomy. (hence the name: vas-ectomy – cutting the vas!).

The chemical reacts and blocks the vas deferens. It also kills sperm when they come into contact with it. The chemical is effective almost immediately after it is injected.

The chemical stays in place until a man decides that he wants to have children. It can then be washed out using another injection which dissolves the polymer and flushes it out of the vas deferens. Another advantage of Vasalgel is that while it blocks sperm, other fluid can still pass through. This should reduce any risk of pain due to back pressure, an occasional issue with vasectomies (fluid backup!)

A variation of this technique is the intra-vas device (IVD). It involves injecting a “plug” into the vas deferens which can be removed later. The IVD filters out the sperm as it passes through the vas deferens.

Initial results of RISUG and IVD are promising, but further research is needed to assess the long-term effectiveness and safety of both techniques. But it seems that this is way to go with men.


Why is it harder to develop birth control for men than women?

That’s the big question. There are a couple of reasons. One is that it’s harder from a biological point of view. If you think about it, it’s a numbers game: Women produce one egg a month, while men are producing millions of sperm constantly (as a side note: it has been calculated that a man will produce in a lifetime an average of 110 liters of semen – the equivalent of an average bathtub! Or a big fish tank! I hope they are wrong!) With women, you can take advantage of their normal monthly cycle with the birth control pill. There’s nothing equivalent to that in men. We produce sperm relentlessly! 1,500 sperm cells per second! That’s right, you read well!

Other reason is the un-willingness of men to take some side effects (hormonal especially).

And the third reason is that funding this type of research is tough. In fact, there’s more money dedicated to figuring out how to best to sterilize your family dog than there is to research new male contraceptives! Nice, right?

For women, it will be life-changing to have men help out in the contraceptive department, with a method other than condoms. They could replace or supplementing a woman’s existing method—both partners taking something is better than one.

This would be a game changer for couples, as well as single women and men. It would move the contraceptive burden into shared territory.


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Can you swallow your tongue?

You have probably heard this before: when you see someone passing out or having a seizure, in general, losing consciousness due to various reasons, there seems to be always someone saying that you should try to get the poor fella’s tongue out of his mouth so he will not swallow it. This is a myth.

But before explaining that, let’s get some facts straight.

Tongue is an amazing muscular organ that is covered by a thin mucous membrane. It lies partly in the mouth cavity and partly in the oropharynx. It is highly mobile and can be shifted into a number of different positions and also assume various shapes. The tongue’s primary function is often seen as that of being the organ of taste, however, its role in various other activities is also crucial.

Functions of the tongue:

  • Taste. The taste buds, the sensory receptors for taste, are located on the tongue.
  • Speech. The movements of the tongue are crucial for articulation.
  • Chewing and swallowing. The tongue helps the teeth and other parts of the mouth with chewing food and passing it down the throat as the first part of the swallowing process.
  • Cleaning. The movements of the tongue dislodge food particles stuck between the teeth, gum and cheek so that it can be spat out or swallowed.

The tongue is a muscular mass and although it is made up of several muscles, all act in conjunction with each other to perform various movements. The tongue muscles can be divided into the intrinsic and extrinsic groups. Broadly the intrinsic muscles can alter the shape of the tongue while the extrinsic muscles change the position of the tongue.

Anatomy of the mouth

Other interesting facts about the human tongue:

  • Tongue is the only muscle in human body that works without any support from the skeleton! It is a biological structure known in mammals as muscular hydrostat; the most common recognized muscular hydrostat is the trunk of an elephant.
  • There are specific segments on tongue for sensing different tastes. The notion that different parts of the tongue is responsible for sensing different types of tastes (in other words, there are taste belts) is actually a myth. Our tongue can taste sour, sweet, bitter, salty and umami. Umami is actually a very new variant of taste discovered by a Japanese scientist who found that the chemical that is responsible for this taste is monosodium glutamate (the famous “MSG”).
  • The tongue is THE STRONGEST muscle in entire body. However, it is at the same time, one of THE MOST SENSITIVE muscles as well.
  • Women have shorter tongues compared to males.
  • Our tongue has a very unique property. It is incapable of detecting taste if it is dry! This means that if you place a piece of lemon on a dry tongue, you will not be able to tell that it is sour. The tongue gets its ability to sense taste only in the presence of saliva that keeps it moist. The most common source of dry mouth/tongue is the prescribed medication.
  • Sticking out your tongue is considered unacceptable behavior in many cultures, but it is a sign of respect in others. In Tibet, sticking out the tongue is a greeting. When two people meet, they stick out their tongues at each other. Among the Maori people of New Zealand, sticking out the tongue is part of a war chant and is meant to intimidate the enemy. If you want to see it yourself and you like rugby, please watch on YouTube the ceremonial Haka before a rugby game of New Zealand (“All Blacks”).

There is a common belief that you can swallow your tongue but it is not actual possible to do it. What the people would actually mean is that tongue can block the opening of the airway (trachea); one of the first things you are taught in basic life support is that if someone is having difficulty breathing you should tilt his/her head and lift the chin; this will help to remove the tongue as an obstruction.

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The Science behind the Grey Hair and Debunking its myths

I was always intrigued by why people turn grey hair at some point in their life.  What is the science behind this? And what is the truth behind the all the myths about grey hair?

Let’s take it step by step.

Scientists have long known that greying is the result of a gradual disappearance of melanin in hair follicles – melanin is the protein responsible for giving hair its color.

Anatomically, each hair on our heads is made up of two parts:

  • a shaft — the colored part we see growing out of our heads and beards (males only!)
  • a root — the bottom part, which keeps the hair anchored under the scalp

The root of every strand of hair is surrounded by a tube of tissue under the skin that is called the hair follicle. Each hair follicle contains a certain number of pigment cells. These pigment cells constantly produce a chemical called melanin that gives the growing shaft of hair its color of brown, blonde, red, and anything in between.

Melanin is the same substance that makes our skin’s color fair or darker. It also helps determine whether a person will burn or tan in the sun. The dark or light color of someone’s hair depends on how much melanin each hair contains.

As we get older, the pigment cells in our hair follicles progressively die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer have as much melanin and will become a more transparent color — like gray, silver, or white — as it grows. As people continue to get older (and they will!), fewer pigment cells will be around to produce melanin. Eventually, the hair will look completely gray. This is, in short, the science behind grey hair.

And now the myths:

Can you give yourself grey hair?

There is no scientific evidence to back this myth up. One compelling argument that you will often hear is “just look at the USA presidents when they took office and look again when they leave the office!” It seems that all of them will turn greyer during this time. But this is just an observational study and there is no science behind it. Stress seems to accelerate this process, but if you want to blame someone for this, blame your parents; genetics plays a big role in this one. If you want to know how soon you will grey, take a look at your parents or ask them when they started to grey. This is a pretty accurate indicator. What is written in your DNA nobody can change or erase.

If I pluck one grey will it grow 2-3 instead?

You probably heard this before. Just old folklore. There is not one bit of truth behind this. Plucking will remove the hair, but there is no connection with the strands around that hair. And it will not remove the hair follicle. And the new hair growing from that follicle will continue to grow as it was doing before: with no pigmentation! And even worse, sometimes, it can damage the follicle so instead of one hair growing back, you might end up with no hair at all! Just leave it alone, and go with the flow! Grey hair looks great on men past 40!

If I dye excessively will my hair turn grey faster?

No, there is no science behind this either. You can breathe easily now. Just invest in some natural, good-quality products (herbal dyes or hypo-allergenic dyes, without PPD or ammonia) and have fun. But don’t tell your teen kids yet!

Is smoking causing me grey hair?

This one seems to be Plausible. Or even True. You are far more predisposed to to greying hair as compared to an individual who do not smoke. Smoking has been said to play a role in the ageing process of hair since it creates oxidative stress. A study in 2013 showed a link between smoking and turning grey before 30. So if you want to have dark and lustrous hair, consider quitting smoking altogether. The benefits far outweigh the short-lived rush of pleasure when smoking cigarettes!

Is the excessive sun exposure responsible for grey hair?

I would say for this one that is Plausible. Some scientist say No, some say Yes. It’s more about what happens inside of the cells than external factors. Long exposure to sun will create hydrogen peroxide in excess that will eventually play a part in the process of greying but the extent of this in the whole picture is not known yet. Gray hair is more susceptible to sun damage, since it has less melanin. So it doesn’t hurt to wear a hat.

Can white hair turn grey overnight?

Scientifically and medically, this is impossible; there is no mechanism by which hair could organically turn white, either suddenly or overnight. Hair is always dead. Once the hair grows out of the head, it can’t be influenced by any psychological or physiological processes in the body. It would be weeks before the effect of some extreme shock/stress would be visible because only the root would be affected.

But…historically, there were tales of people whom, sentenced to death penalty, turned grey overnight. The best examples that I could find were: the French queen, Marie Antoinette (1755-1793) when led to the guillotine at the age of 38, during the French Revolution, her hair is said to have turned white the night before her execution. This is even now called Marie Antoinette syndrome in the dermatological circles, when someone suddenly turns grey/white in short term.

Another famous example is the English lawyer Sir Thomas More (1478-1535), who was canonised and declared a martyr in 1935 by the Pope Pius XI, was executed in the Tower of London in 1535, and again his hair was reported to have turned white before his death. He was opposing the Henry VIII separation from the Catholic Church, opposing thus the Protestant Reformation.

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Are Canker Sores contagious?

Medically known as aphtous ulcers, these nuisance, small lesions on the inside of your mouth or at the base of the gums, are a medical mystery in its own right. We don’t know how and why they appear. Mystery. Medicine doesn’t have all the answers, after all.
The work canker means “spreading ulcer” and it was the common word for the disease that we all now as cancer until 1700 and in time its meaning shifted to become a general term for ulceration.
They are very common. In fact, they are so common, that nobody is keeping track of its epidemiology, and when researched, all you can get is a wide range of percentages, like 5-70% incidence rate in Canada.
Despite many studies trying to identify a causal microorganism, canker sores do not appear to be infectious, contagious, or sexually transmitted. Immune mechanisms appear at play in persons with a genetic predisposition to oral ulceration. It appears that they are the result of a T cell–mediated response to the antigens of Streptococcus sanguis, a nasty bacterium.
People often confuse them with the Cold sores, which are completely different. Cold sores, also called fever blisters or herpes simplex (HPV) type 1, are groups of painful, fluid-filled blisters. Unlike canker sores, cold sores are caused by a virus and are extremely contagious. Also, cold sores typically appear outside the mouth – usually under the nose, around the lips, or under the chin – while canker sores occur inside the mouth.
What triggers these pesky things on the inside of your mouth?
Stress or tissue injury is thought to be the cause of simple canker sores. Certain foods, some people reported citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes, and strawberries), can trigger a canker sore or make the problem worse. Sometimes a sharp tooth surface or dental appliance, such as braces or ill-fitting dentures, might also trigger canker sores.
In the matter of how you treat them, and because we don’t know what exactly cause them, medicine doesn’t have much to offer. Conventional medicine says Just pay attention to the triggers and avoid them. Complementary medicine will offer you coconut oil, sage or honey rub, cayenne cream, aloe rinse, gargle with warm salt water etc. With or without treatment, the pain lessens after 2-3 days and the canker sores will heal in 7-10 days anyway.
So, to answer to the question from the title, canker sores are not contagious (if you were afraid of that) and they will spontaneous heal in 7-10 days. The miracles and mysteries of the human body.

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Why do you laugh when tickled?

Have you ever wondered why do you laugh when tickled? And what is the mechanism behind this?
Well, I had and I want to share with you my findings.
You don’t spend a lot of time in any medical school learning about laughter. Almost at all. All you hear is that laugher is good for you, it’s “healthy” to have a good laugh, a hearty “belly” laugh, when you think you belly is going to explode…it is very soothing, alleviates pain (it is analgesic!), improves your mood, boosts your immune system and relieves stress. That’s all you can get in medical school. When it is studied in a more serious and scientific manner, it even has a Latin name, Gelotology (from the Greek gelos, meaning laughter) which is the study of laughter and its effects on the body. There is even a rare form of seizure, called gelastic seizure, often found in children, that causes one to laugh or giggle uncontrollably, with no apparent cause and no joyfulness in it, rather unpleasant and sardonic sounds.
Laughter is a complex process that requires the coordination of many muscles in the body. It is estimated that around 40-45 muscles take part in the laughing process, especially the facial muscles. We, humans, do have 53 facial muscles, but who’s counting?
Some researchers have tried to decipher the purpose of laughter and for me it is obvious that the reason for laughter has something to do with making human connections, a social signal of sorts that we are optimistic, we are enjoyable and fun for the potential mating partner. Who doesn’t want after all?
Studies have shown that people are thirty times more likely to laugh in social settings than when they are alone.
What about the connection between tickling and laughing?
It’s been studied by the evolutionary neuroscientists and biologists in Germany and they believe that this is an actual primal reflex. The physiological explanation of it goes like this: the part of the brain that tells us to laugh when we experience a light touch (the hypothalamus) is also the same part that tells us to expect a painful sensation (which is why you may accidentally lash out at someone who is trying to tickle you).
This is seen and interpreted by the brain as a defensive mechanism. We have evolved to send this signal out to show our submission to an aggressor, to dissipate a tense situation and prevent us from getting hurt. This also cast new light on why some people even start to laugh just with the threat of being tickled. Do you anyone like that? I do.
Our most ticklish parts are coincidentally our weakest spots, such as our neck, armpits or our stomach, and so the team at Tuebingen, Germany hypothesized that parents would have tickled their offspring to train them to react to danger and that the laughter of tickling is an acknowledgement of defeat.
So, why can’t we tickle ourselves? The scientists responded that, the cerebellum at the back of the brain tells you that you are about to self-tickle so the brain doesn’t waste any time and resources to interpret these signals, categorizing them as unimportant and irrelevant.
Are we the only mammals that laugh when tickled?
No, apes (gorillas, chimpanzees, bonobos and orangutans) laugh just like us when tickled! And the rats too! But they giggle at 50 kHz, which is outside of human audio range.
Now do me a favor and laugh at this article and give you heart and diaphragm a good workout! And stop tickling yourself, I am telling you, it is not working, no matter what!

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Why do men have nipples?

Because we are built to a common pattern. All people contain the genetic information to be either male or female, but in the vast majority of people only one alternative develops. All humans are born with rudimentary potential breasts. In the case of women they are triggered to develop hormonally as a secondary sexual characteristic. Men not only have nipples, but undeveloped (pre-pubescent) breasts.

It seems to me that all fetuses, male and female, initially develop as females. Hence the nipples. When the fetus’ pituitary develops and estradiol can convert to testosterone, then the male characteristics begin to show. Had there been no testosterone, the child would probably be a hermaphrodite. However, all humans have both estrogen and testosterone, so this is rarely a problem. The same chemical (FSH or follicle stimulating hormone) floods the secondary sex hormone. However, the conversion to primarily testosterone is what causes the male characteristics. Almost all mammals have nipples in both the male and females,proving this isn’t just a human thing but takes place in all species that use this form of reproduction. Anyway, they have entertainment value!

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