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What is this thing found in my saliva?

What is this thing found in my saliva?


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Found in my saliva (Optical microscope 40x)


Saliva is a mixture of water, mucus, antibacterial substances, and digestive enzymes. One of the most recognizable digestive enzymes in human saliva is amylase. This enzyme is able to break down the starch in our food to simpler and more easily digestible sugars like glucose and maltose. Whenever we chew, we are activating salivary glands in preparation for the breakdown of our meal.

Saliva has a number of functions within the digestive system beyond breaking down starches. Saliva also helps keep our mouth and digestive tract lubricated, which ensures it functions properly. Salivary glands typically function without issue, but a blockage or infection within the salivary glands can cause significant pain and discomfort.

The salivary glands are located in several areas around the mouth and have ducts connected to both the upper and lower jaw. This ensures that saliva evenly coats the inner lining of the mouth. You can feel the end of these ducts just below your tongue and along the inside of your upper lip. If you eat something with a lot of starch or sugar, you can also feel the salivary glands activating and releasing saliva.


In saliva, clues to a 'ghost' species of ancient human

In saliva, scientists have found hints that a "ghost" species of archaic humans may have contributed genetic material to ancestors of people living in Sub-Saharan Africa today.

The research adds to a growing body of evidence suggesting that sexual rendezvous between different archaic human species may not have been unusual.

Past studies have concluded that the forebears of modern humans in Asia and Europe interbred with other early hominin species, including Neanderthals and Denisovans. The new research is among more recent genetic analyses indicating that ancient Africans also had trysts with other early hominins.

"It seems that interbreeding between different early hominin species is not the exception -- it's the norm," says Omer Gokcumen, PhD, an assistant professor of biological sciences in the University at Buffalo College of Arts and Sciences.

"Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva," he says. "When we looked at the history of the gene that codes for the protein, we see the signature of archaic admixture in modern day Sub-Saharan African populations."

The research was published on July 21 in the journal Molecular Biology and Evolution. The study was led by Gokcumen and Stefan Ruhl, DDS, PhD, a professor of oral biology in UB's School of Dental Medicine.

A tantalizing clue in saliva

The scientists came upon their findings while researching the purpose and origins of the MUC7 protein, which helps give spit its slimy consistency and binds to microbes, potentially helping to rid the body of disease-causing bacteria.

As part of this investigation, the team examined the MUC7 gene in more than 2,500 modern human genomes. The analysis yielded a surprise: A group of genomes from Sub-Saharan Africa had a version of the gene that was wildly different from versions found in other modern humans.

The Sub-Saharan variant was so distinctive that Neanderthal and Denisovan MUC7 genes matched more closely with those of other modern humans than the Sub-Saharan outlier did.

"Based on our analysis, the most plausible explanation for this extreme variation is archaic introgression -- the introduction of genetic material from a 'ghost' species of ancient hominins," Gokcumen says. "This unknown human relative could be a species that has been discovered, such as a subspecies of Homo erectus, or an undiscovered hominin. We call it a 'ghost' species because we don't have the fossils."

Given the rate that genes mutate during the course of evolution, the team calculated that the ancestors of people who carry the Sub-Saharan MUC7 variant interbred with another ancient human species as recently as 150,000 years ago, after the two species' evolutionary path diverged from each other some 1.5 to 2 million years ago.

Why MUC7 matters

The scientists were interested in MUC7 because in a previous study they showed that the protein likely evolved to serve an important purpose in humans.

In some people, the gene that codes for MUC7 holds six copies of genetic instructions that direct the body to build parts of the corresponding protein. In other people, the gene harbors only five sets of these instructions (known as tandem repeats).

Prior studies by other researchers found that the five-copy version of the gene protected against asthma, but Gokcumen and Ruhl did not see this association when they ran a more detailed analysis.

The new study did conclude, however, that MUC7 appears to influence the makeup of the oral microbiome, the collection of bacteria within the mouth. The evidence for this came from an analysis of biological samples from 130 people, which found that different versions of the MUC7 gene were strongly associated with different oral microbiome compositions.

"From what we know of MUC7, it makes sense that people with different versions of the MUC7 gene could have different oral microbiomes," Ruhl says. "The MUC7 protein is thought to enhance the ability of saliva to bind to microbes, an important task that may help prevent disease by clearing unwanted bacteria or other pathogens from the mouth."


5 Spiffy Facts about Spit

An underappreciated body fluid is emerging as a powerful tool for research, medical diagnosis and health. Spit, as it turns out, contains all sorts of juicy information.

According to researchers at Johns Hopkins University's Center for Interdisciplinary Salivary Bioscience Research — yes, a research center dedicated to spit — saliva holds a "treasure trove" of data that is easily collected and inexpensively analyzed. It has the potential to expose secrets of human biology and genetics, as well as helping combat disease. "There's lots of potential in exploring what's in saliva," said Doug Granger, the center's director.

But what can spit do for you?

Spit screening

One-third of heart attack victims drop dead without ever knowing they had high cholesterol, hypertension or the other factors that increased their risk of cardiac arrest. That's partly because the blood test currently used to diagnose a person's heart disease risk is quite the ordeal — it's painful, requires a clinic visit, and takes weeks to be processed — and so most people don't take it as often as they should.

Now, in a new study, Granger and his colleagues have proposed a saliva test to replace the standard blood test. According to the researchers, spit contains the same protein, called C-reactive protein, that indicates a risk of heart disease when found in blood at elevated levels, and spit can therefore give a rough proxy of a patients' heart health. Once a saliva test is available, "more people would be willing to have the test done. It could be done on a more regular basis, even in their homes," Granger said in a press release.

Your father's daughter?

Research shows that daughters who have warm relationships with their fathers begin puberty later, wait longer to start dating and having sex, and are more likely to be monogamous. But why? As detailed in a recent paper by Granger and his team, the answer may be swimming in spit.

The researchers found that when a girl's father-daughter relationship is characterized by rejection, chaos and coercion, her saliva exhibits lower-than-normal levels of the stress hormone cortisol in the morning, and elevated cortisol levels when she is discussing problems or anxieties with friends. These off-balance levels indicate emotional over-sensitivity to stressful situations, a trait that can negatively affect life choices and stress management. [Why Stress is Deadly]

Salivary signs of stress

Stress triggers the body's fight-or-flight response, causing, among other things, a rush of adrenaline, an increased heart rate and salivation. The salivary glands flood the mouth with an enzyme called salivary alpha-amylase (sAA), and this can serve as a marker of stress.

The stress or emotional trauma that a pregnant woman experiences can affect the health of her fetus. The Johns Hopkins team has developed a method of gauging the impact of a mother's stress on her unborn baby by monitoring sAA levels in her saliva. In a study published in February, they identified the way sAA levels naturally change over the course of pregnancy, and the pattern by which they vary throughout the day this lays the groundwork for future research investigating the effect of unusually high stress levels on infants.

Spit exposure

Pre-mastication — the act of pre-chewing adult food and feeding it to one's baby — was standard practice among our blender-lacking ancestors and remains common in many of the world's cultures. Now, it may be coming back in vogue in the West, too, thanks to research indicating a mother's saliva helps boost her infant's immune system.

By exposing infants to traces of disease pathogens present in a mother's spit, pre-mastication gears up their production of antibodies, teaching their immune systems how to deal with those same pathogens later in life. It could also reduce their risk of the autoimmune diseases, such as asthma, that are common in industrialized countries — epidemiology evidence indicates that these ailments result from underexposure to pathogens before age 2.

Fortunately, spit is also swimming with antibodies that reduce the infectiousness of the bacteria in their midst this means exposing babies to spit gives them a taste of pathogens while usually preventing them from getting sick. [Is a Dog's Mouth Cleaner than a Human's?]

Genetic spitprint

Your spit contains your entire genetic blueprint, and in a form that may be easier to work with than DNA extracted by other methods. "One-half of an eyedropper drop [of spit] is enough to get a reasonable sample of DNA," Granger said. "Samples can be frozen and thawed multiple times. They can be sent through the mail, and we're able to extract high-quality, high-quantity DNA."

Follow Natalie Wolchover on Twitter @nattyover. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.


Salivary Secretion in Human Beings | Digestive System

Saliva is the first digestive juice to come in contact with food.

Saliva is secreted by three major salivary glands namely:

ii. Submandibular (sub-maxillary)

Apart from these, there are minor salivary glands in the floor of the mouth, pharynx, tongue and cheeks.

Composition of Saliva:

On an average, the rate of secretion of saliva is about 1 ml/minute.

i. Total volume/day = 1-1.5 liters

vi. Electrolytes: Na + , K + , Ca ++ , CI – , HC03 – , PO4

i. Salivary—ptyalin (salivary amylayse)

Mechanism of Secretion of Saliva:

There are two theories that try to explain the mechanism of salivary secretion:

Secretion of saliva is an active process because it involves increased metabolism, utilization of energy substrate and increased oxygen consumption. The secretion from the acini is called the primary secretion. It contains water and electrolytes similar in composition to plasma besides the other salivary proteins.

Unlike other glands, the duct system of salivary glands is actively involved in modifying the composition of saliva, e.g. in the striate duct of the epithelium reabsorbs Na + in exchange for K + . This epithelium also actively secretes HCO3 – . Therefore, the final saliva reaching mouth has more K + and HCO3 – and less of Na + and CI – compared to the primary secretion.

According to this theory, saliva is an ultra filtrate of plasma, very much like glomerular filtrate in the kidney. The pressure for filtration is provided by arterial blood pressure. This theory is not accepted because even when the pressure in the salivary gland is higher than the arterial blood pressure, the salivary secretion continues.

The saliva that is collected from the mouth is contributed by all the salivary glands and the fraction from the different glands will be 70% from sub­mandibular, 25% from parotid and 5% from sublingual.

Regulation of Secretion of Saliva:

Salivary secretion regulation is brought about by both neural and the hormone (hormonal) mechanisms. Salivary secretion is a spontaneous process subject to modification by other factors. Effect of stimulation of nerves supplying salivary glands.

a. Parasympathetic secretomotor fibers:

As the name secretomotor implies, parasympathetic stimulation increases the volume of salivary secretion profoundly.

The secretion is rich is ptyalin.

This is because of two reasons:

i. The parasympathetic nerve fibers stimulate the acinar cells directly.

ii. They cause vasodilatation in the salivary gland increasing the blood flow.

a. The mechanism of vasodilatation by the parasympathetic nerves in salivary gland is brought about by acetylcholine.

b. Parasympathetic stimulation also liberates VIP (vasoactive intestinal polypeptide). This can also cause vasodilatation.

c. Parasympathetic stimulation also secretes kallikrien, an enzyme found in the acini, kallikrien acts on two globulins of plasma and forms bradykinin which is a very powerful local vasodilator. Increase in the blood flow is not abolished by atropine suggesting that acetylcholine is not responsible for vasodilata­tion.

b. Sympathetic stimulation:

Sympathetic stimulation causes vasoconstriction and reduction in blood supply to the salivary glands.

As far as the direct action on acini is concerned, the sympathetic stimulation has no effect on parotid gland in man. In the case of submandibular gland, in man there is increase in secretion but the amount is small and the secretion is thick and viscous due to high mucin content. Sympathetic stimulation causes contraction of myoepithelial cells.

Reflex Regulation:

Salivary secretion is brought about by reflex action:

a. Unconditioned reflex:

This reflex is present at birth. This is due to the stimulation of receptors in the mouth by chemical substances which are present in food and even mechanical stimulation brought about by food in mouth.

Presence of food in the mouth brings about immediate secretion. Exclusive mechanical stimulation of oral cavity by any means also stimulates salivary secretion. For example, maneuver of oral cavity by dentists, movement of tongue thereby coming in contact with cheeks.

The most important stimulus is the presence of food in the mouth. The details of the influence of unconditioned stimulus on salivary secretion is detailed in Fig. 5.6.

This reflex is acquired during the life. Here, the stimulation process originates not from the mouth but from the organs of special senses, especially sight and smell, to a certain extent even hearing.

In the case of human beings, the previous experiences associated with the supply of food like the sight, smell can give rise to secretion of saliva. In animals, the conditioned reflex for secretion of saliva can be experimentally produced for sight, sound or smell of food.

Pavlov demonstrated conditioned salivary secretion in dogs. Every time a dog was served with food, after ringing of bell. After few days, just the ringing of the bell alone without food being served causes secretion of saliva. During the training period, the dog learns to associate ringing (sound) of bell with supply of food.

Paralytic Salivary Secretion:

When the chorda tympani nerve supplying the sub- mandibular and sublingual glands is cut, although these fibers are the secretomotor fibres, still the two glands secrete saliva initially less in volume but it starts increasing to a maximum by about the 7th or 8th day after the nerve is cut. This rate of secretion remains constant for about 3 weeks and by about 6 weeks the secretion almost stops.

The reasons for the paralytic salivary secretion are:

Chorda tympani, the parasympathetic nerve cutting, means cutting the preganglionic fibers. The postganglionic fibers remain active and secrete acetylcholine for some time.

2. Increased excitability of sympathetic fibers:

On cutting the parasympathetic nerve, the excitability of sympathetic fibers increases and they get stimulated more easily.

3. Denervation hypersensitivity:

Cutting of the parasympathetic chorda tympani nerve makes the gland more sensitive to circulating chemical substances, like acetylcholine.

Augmented Salivary Secretion:

Stimulation of sympathetic and parasympathetic nerve fiber supplying the salivary glands simultaneously causes an increase in secretion which is far more than the summated effects of individual nerve stimulation added.

Taste is not essential for salivation. Substances which are insipid also stimulate the secretion of saliva. But the rate of secretion of saliva is affected by taste. Substances having sour taste bring about a greater volume of secretion. Composition of saliva whether it is rich in enzymes, mucin or water can be varied according to the food that is presented.

Disorders of Salivary Secretion:

Hyposalivation is decrease in the volume of salivary secretion. It can be caused by anxiety, excitement or irradiation.

b. Hypersalivation or sialorrhea:

This can occur in pregnancy and parotitis (e.g. mumps), tumors in oral cavity.

c. Xerostomia (dry mouth):

This is a rare condition in which the salivary glands are deficient or absent right from birth. So there may be scanty secretion of saliva.

d. Chorda tympani syndrome:

Sometimes the chorda tympani nerve may be cut accidentally. When the fibers regenerate, they miss their normal target and instead innervate the sweat gland of skin in the sub­mandibular region.

In such a case, whenever there is stimulation for salivation, say while eating, there is also significant sweating of skin in sub mandibular region. It must be noted that now the sweat glands are also supplied by some parasympathetic nerve fibers that were supplied to salivary glands earlier.


What can your spit tell you about your DNA?

­People spit for a variety of reasons. We've all employed the technique to remove a hair or some other distasteful object from our mouths. People who chew tobacco do it for obvious reasons. Ball players do it because they're nervous, bored or looking to showcase their masculinity. And people in many different cultures spit on their enemies to show disdain.

­Thanks to a phenomenon known as direct-to-consumer genetic testing or at-home ­genetic testing, people are spitting today for a much more productive (and perhaps more sophisticated) reason -- to get a glimpse of their own DNA.

That's right. Your saliva contains a veritable mother lode of biological material from which your genetic blueprint can be determined. For example, a mouthful of spit contains hundreds of complex protein molecules -- what scientists call enzymes -- that aid in the digestion of food. Swirling around with those enzymes are cells sloughed off from the inside of your cheek. Inside each of those cells lies a nucleus, and inside each nucleus, chromosomes. Chromosomes themselves are made up of DNA, the now-ubiquitous shorthand for deoxyribonucleic acid, the double-stranded molecule that gets much of the credit for what we look like and how we act.

Of course, you can't look at your own spit and see sloughed-off cells, the DNA they contain or the genetic information coded in the long chain of base pairs. You need special equipment and scientists who know how to use it. You also need trained counselors who can help you interpret the data once you get it back. That's where companies like 23andMe, deCODEme and Navigenics come in. They give you the tools, resources and infrastructure necessary to learn more about what makes you tick at a cellular level. They each do it slightly differently, and they each reveal different aspects of your DNA profile.

Let's see how these companies transform spit into state-of-the-art science.

­Genetic tests analyze DNA present in blood and other tissue to find genetic disorders -- diseases linked to specific gene variations or mutations. About 900 such tests exist, ranging from more invasive procedures that require a trip to the hospital to the new generation of at-home tests that demand nothing more than spitting into a sterile, mini-sized spittoon. Here's a quick overview.

Prenatal testing may involve sampling and testing the DNA of a fetus. One common test under this umbrella is amniocentesis, which requires a physician to insert a needle into the water-filled sac surrounding the fetus to withdraw a small amount of fluid. In a lab, workers culture fetal cells from the amniotic fluid to obtain a sufficient quantity of DNA. Then they analyze the DNA for chromosome abnormalities that can lead to diseases or conditions such as Down s­yndrome and spina bifida.

Another approach to genetic testing is gene sequencing, which identifies all of the building blocks, or nucleotides, of a specific gene. Once a person's gene has been sequenced, doctors can compare the gene against all known variations to see if it is normal or defective. For example, inherited alterations in the genes called BRCA1 and BRCA2 (short for "breast cancer 1" and "breast cancer 2") are associated with many cases of breast cancer.

Next up is single nucleotide polymorphism (SNP) testing. Nucleotides have three parts: a phosphate group, joined to a pentose sugar, bonded to a nitrogenous base. You can probably recite the various bases along with us -- adenine, guanine, cytosine, thymine and uracil (in RNA). Together, these nucleotides can combine in nearly infinite ways to account for all of the variation we see within and between species. Interestingly, the sequence of nucleotides in any two people is more than 99 percent identical [source: 23andMe]. Only a few nucleotides separate you from a complete stranger. These variations are called single nucleotide polymorphisms, or SNPs (pronounced "snips").

To run a SNP test, scientists embed a subject's DNA into a small silicon chip containing reference DNA from both healthy individuals and individuals with certain diseases. By analyzing how the SNPs from the subject's DNA match up with SNPs from the reference DNA, the scientists can determine if the subject might be predisposed to certain diseases or disorders.

­SNP testing is the technique used by almost all at-home genetic testing companies. It doesn't, however, provide absolute, undisputed results.

From Spit to SNP: The Basic Process

­Unlik­e at-home pregnancy testing, which delivers results to the user as she watches, at-home genetic testing isn't so simple or home-based. You do get to provide the sample at home, but everything else requires the help of off-site trained scientists. You can't simply spit in a cup, dip in a wand and read the results. This is how it works:

  1. Visit the Web site of your preferred service provider. Three popular services are 23andMe, Navigenics and deCODEme. Next, open an account and order a test. Prices can range from $100 to $2,500, depending on the package you select.
  2. After your order is processed, the company mails a kit to you that includes any necessary equipment.
  3. Now comes the fun part. Using the supplied cup or tube, start collecting your spit. About 30 milliliters (2 tablespoons) of saliva are required to get a sufficient number of cheek cells. The deCODEme service actually uses a buccal DNA collector, which is a stick with rough paper on one end. You rub the paper on the inside of your cheek to collect the cells.
  4. Seal up your sample and place it in the conveniently provided preaddressed envelope.
  5. Mail it and wait patiently.
  6. The lab extracts DNA from your cheek cells and conducts SNP testing to see if you have any markers for certain diseases or disorders.
  7. When your results are ready, usually in about eight to 10 weeks, they're uploaded to your account and you're alerted by e-mail that the data is ready to be reviewed.
  8. What happens next depends on the service provider. Navigenics makes genetic counselors available to help you understand and interpret the data. Social networking is a major goal of the 23andMe service. You can use the company's site to network with other individuals who might share similar backgrounds or proclivities, like wet earwax. Seriously.

­All of the service providers offer security measures to protect your data and allow you to choose how much data is made available to you.

If you're not self-conscious about spitting in front of others, you might consider attending or hosting a spit party. The concept comes courtesy of 23andMe, which has hosted several such parties. A typical saliva soirée has the usual mingling and finger food. But it also provides an opportunity to sign up for the testing service. After signing up, guests receive a sample collection kit, retire to a comfortable location and start coughing it up.

­­­So what, exactly, do a few milliliters of spit tell you? The most important thing you'll learn is what kind of genetic markers you carry.

A genetic marker is any alteration in your DNA that may indicate an increased risk of developing a specific disea­se or disorder. Because SNPs are, by their very definition, variations in DNA, they can be used as flags or markers for nearby DNA that affects your health.

Different se­rvice providers identify different genetic markers. For example, 23andMe identifies your risk for developing lupus, while deCODEme and Navigenics don't. These latter companies, however, test for markers of Alzheimer's disease, which isn't included in 23andMe's repertoire. The table below compares the service providers across 10 other important diseases and disorders [source: Genetics and Public Policy Center].

Understanding your susceptibility to certain diseases is a powerful tool. Say, for instance, your at-home genetic test reveals you're predisposed to develop osteoporosis. You can use this information to take a more proactive role in your own health care. You might decide to take supplements to ensure you're getting enough calcium and vitamin D. You might also engage in regular weight-bearing exercise and opt to have a bone density test to determine your risk for future fracture. These kinds of decisions are part of a growing trend that finds more patients -- well educated and computer-literate -- assuming control of their own health care.

­Better health is not the only thing you can get out of your spit. You can also trace your ancestral roots. This is possible because closely related individuals have more similarities in their DNA. By comparing your genetic information to that of people from around the world, you can fill out a comprehensive family tree, tracing your lineage through either your mother or your father.

The genetics tests we've described so far only analyze bits and pieces of a person's DNA. Given the success of the Human Genome Project, why not sequence an individual's entire genome? The answer comes down to time and money. It takes too long and costs too much to map out all of the 6 billion nucleotides in a person's genome [source: NOVA scienceNOW]. Scientists hope that one day this will be possible. Until then, we'll have to settle for the abridged version of our genetic story.


You might also Like

The one time I was really worried about having brown saliva it wasn't because I was eating or drinking wrong. I was living in a city with very high air pollution and I noticed that my saliva was starting to be discolored. I always wondered if it would have eventually affected my teeth, but I was so concerned about the effect on my lungs that I didn't stay long enough to find out.

It's kind of scary what millions of people are willing to put up with in order to live in a city.

Sometimes the simple explanation is the best one. If you've been eating brown food or drinking brown liquids (like chocolate or coffee) it will probably stain your saliva brown.

That's one reason it's a good idea to brush your tongue with your toothbrush as part of your nightly routine. This helps to remove more bacteria from your mouth, but it can also make sure that any food residue is removed from your tongue as well. Even though coffee isn't likely to cause any bacterial growth, it can still stain your teeth, so I think brushing it away is probably a good idea. clintflint October 16, 2013

Acid reflux might be common, but you still might want to look into why it's happening. Often it has something to do with eating habits and might be related to the type or amount of food someone is eating.

It can do some damage over time and can be very uncomfortable as well, so if you can figure out how to stop it, that's probably a good idea.


Stomach

A large part of digestion occurs in the stomach, shown in Figure 15.11. The stomach is a saclike organ that secretes gastric digestive juices. The pH in the stomach is between 1.5 and 2.5. This highly acidic environment is required for the chemical breakdown of food and the extraction of nutrients. When empty, the stomach is a rather small organ however, it can expand to up to 20 times its resting size when filled with food. This characteristic is particularly useful for animals that need to eat when food is available.

Figure 15.11. The human stomach has an extremely acidic environment where most of the protein gets digested. (credit: modification of work by Mariana Ruiz Villareal)

Which of the following statements about the digestive system is false?

  1. Chyme is a mixture of food and digestive juices that is produced in the stomach.
  2. Food enters the large intestine before the small intestine.
  3. In the small intestine, chyme mixes with bile, which emulsifies fats.
  4. The stomach is separated from the small intestine by the pyloric sphincter.

The stomach is also the major site for protein digestion in animals other than ruminants. Protein digestion is mediated by an enzyme called pepsin in the stomach chamber. Pepsin is secreted by the chief cells in the stomach in an inactive form called pepsinogen. Pepsin breaks peptide bonds and cleaves proteins into smaller polypeptides it also helps activate more pepsinogen, starting a positive feedback mechanism that generates more pepsin. Another cell type—parietal cells—secrete hydrogen and chloride ions, which combine in the lumen to form hydrochloric acid, the primary acidic component of the stomach juices. Hydrochloric acid helps to convert the inactive pepsinogen to pepsin. The highly acidic environment also kills many microorganisms in the food and, combined with the action of the enzyme pepsin, results in the hydrolysis of protein in the food. Chemical digestion is facilitated by the churning action of the stomach. Contraction and relaxation of smooth muscles mixes the stomach contents about every 20 minutes. The partially digested food and gastric juice mixture is called chyme. Chyme passes from the stomach to the small intestine. Further protein digestion takes place in the small intestine. Gastric emptying occurs within two to six hours after a meal. Only a small amount of chyme is released into the small intestine at a time. The movement of chyme from the stomach into the small intestine is regulated by the pyloric sphincter.

When digesting protein and some fats, the stomach lining must be protected from getting digested by pepsin. There are two points to consider when describing how the stomach lining is protected. First, as previously mentioned, the enzyme pepsin is synthesized in the inactive form. This protects the chief cells, because pepsinogen does not have the same enzyme functionality of pepsin. Second, the stomach has a thick mucus lining that protects the underlying tissue from the action of the digestive juices. When this mucus lining is ruptured, ulcers can form in the stomach. Ulcers are open wounds in or on an organ caused by bacteria ( Helicobacter pylori ) when the mucus lining is ruptured and fails to reform.


What is Saliva?

As most of you probably know, the human body is composed of approximately 57-60% water, making it an incredible important part of survival. In fact, it is the foundation of human life, and without it, most people cannot survive more than 3 days. Therefore, it shouldn&rsquot come as a big surprise that one of the body&rsquos major fluids, saliva, is primarily composed of water &ndash about 99%, to be a bit more precise.

However, that isn&rsquot where the story ends, as the other 1% of saliva is incredibly important for human health, and a number of saliva&rsquos functions. Our spit also contains mucus, electrolytes, enzymes and antibacterial compounds, as well as sodium, potassium and bicarbonate. These other elements in saliva help us do everything from protect the enamel on our teeth to strengthening the immune system and ensuring that our digestive process is efficient.

Saliva is formed and secreted from salivary glands, of which there are six (three pairs of two) major ones &ndash the parotid, the submandibular, and the sublingual glands. The parotid glands are in the cheeks, the sublingual glands are beneath the tongue and the submandibular glands are found near the jaw, in the bottom portion of the mouth. All of these glands are controlled by the autonomous nervous system, which is in control of &ldquoautomatic&rdquo actions, or things we can&rsquot control. For example, when you look at a delicious, hot pizza coming out of the oven after a long, hungry wait, the sight, smell and anticipation of eating will cause the release of saliva from these glands.

The saliva itself is produced in acinar cells, which can come in two varieties, serous or mucous. Serous cells make slightly more watery saliva, while mucous cells, as their name implies, makes a thicker, more viscous form of saliva. Serous cells are mainly found in the parotid gland, mucous cells dominate the sublingual gland, and there is a mixture of both in the submandibular gland. The saliva moves from tiny ducts to larger ducts, eventually being released into the mouth, where it can finally go to work! All of this can happen in mere seconds, suddenly filling your mouth with saliva in the moments before that first bite!


How to Treat Excessive Saliva

Treatment for excessive saliva depends on your overall health and other symptoms that you may be having. It is best accomplished by a multidisciplinary team, from primary care physicians to speech therapists, neurologists, and dentists. If you find yourself having excessive saliva in your mouth, it’s essential to consult with your doctor to determine the best treatment plan.

A study in New Approaches in Diagnostics and Treatment recommends that treatment interventions, including speech and swallowing therapy, medications, Botox, and use of oral prosthetic devices, among other things, be used. MedlinePlus notes that a speech therapist can determine if hypersalivation increases the risk of you breathing foods or fluids into your lungs.

Having excessive saliva can be quite uncomfortable, so you must seek out treatment as soon as possible. Consult with your doctor so that together you can find a treatment plan that manages the excessive saliva and makes you feel comfortable and confident.


How cool is this? A worm in my mouth

Jon Allen could feel it with his tongue — a small rough patch that would show up periodically on the roof of his mouth … then inside his cheek … then inside his lip.

It would appear for a day, clear up for a while, but always come back.

An assistant professor in the biology department at the College of William and Mary in Williamsburg, Allen lectures on nematodes and parasites for a living, so on the last day of finals last December when he felt it again, he left his class, grabbed a camera and opened wide.

And there in the snapshots was clear, squiggly evidence just under the skin of his lower lip of the sinusoidal meandering of a parasitic nematode.

He had a worm living in his mouth.

The consummate scientist was delighted.

"I knew it was a nematode," Allen said. "I got really excited because I could see it. This was too good to be true."

He did his research and discovered there was only one parasitic worm capable of living in the human mouth: Gongylonema pulchrum, or G. pulchrum, also known as the "gullet worm" for its preferred habitat.

He also knew that G. pulchrum infections are considered rare in humans — more typical hosts are cattle, pigs, rabbits, bears, monkeys and the like.

In fact, if his suspicions were confirmed, Allen would become only the 13 t h case ever reported in the United States.

Allen also knew he wanted it removed.

So he took his pictures, his research documents and his Ph.D. to an oral surgeon — who informed Allen he didn't see a thing out of the ordinary.

Disappointed, Allen was nonetheless undeterred.

He shot off an email to his neighbor, Aurora Esquela Kerscher, a molecular cell biologist at Eastern Virginia Medical School in Norfolk and an expert in small-scale nematodes:

"I'm convinced I have a rare nematode parasite in my mouth, and I'm looking for someone interested in such things (nematodes, not my mouth) to help me ID this," he wrote. "After getting rebuffed by my oral surgeon today, I've decided to retrieve the specimen from my mouth on my own."

So in the middle of the night, after tucking his restless 3-year-old son back into bed, Allen headed to the bathroom with a pair of ultra fine forceps.

With his wife, slightly grossed out, aiming a flashlight into his mouth, Allen gently scraped his cheek lining to get a good handle on the nematode. He nipped it carefully with the forceps and tugged.

The worm slipped his grip once, then twice. Allen had visions of breaking it. Or of accidentally swallowing it.

He buckled down a third time and nipped it with more force, and the worm came out wriggling at the end of his forceps — translucent, as thin as a slip of thread, and about 2 centimeters long, or three-quarters of an inch.

"It looks tiny in a jar, but it looks big when it's in your lip," said Allen.

He couldn't quite bring himself to kill it right off, so he dropped it in a jar of his own saliva. Then, still in his pajamas, he carted it to his lab at William and Mary to examine it under a microscope.

"It looked like a textbook example of the worm," Allen said. "So I knew right away I had identified it correctly."

Later, Kerscher sectioned off a portion of the specimen — which they nicknamed Buddy — for genetic tests that confirmed its identity with 99 percent certainty.

"We're both scientists," Kerscher said with a laugh. "We're thinking, 'How cool.'"

A rare breed?

If you're going to host a parasitic worm, G. pulchrum is the one to get, the two scientists say.

"It's a parasite, but it's not going to kill you," Kerscher said. "It's not making you sick. If you had an intestinal parasite or virus, you're getting quite sick — but this one, you're fine."

So long as it lives in the back of the throat or the esophagus, the worm is undetectable. Usually only when it gravitates to the soft tissue of the oral cavity can the host feel something amiss.

Most cases reported in this country occurred in the southeastern states, but at least two were in large cities in the Northeast.

There are fewer than 60 reported cases around the world — most in the Soviet Union, Europe and the Middle East.

But the two scientists suspect G. pulchrum infections could be vastly underreported or misdiagnosed. Or, like Allen's, dismissed.

In a case in Iran that appeared in the Journal of Helminthology in 2006, an Iranian woman who reported "a one-year history of feeling a migratory creeping sensation in the neck region and upper part of the digestive tract" was first diagnosed with delusional parasitosis.

Only after treating and examining her again did doctors finally detect "two delicate, white, thread-like worms" and remove them.

Insects are intermediate hosts for G. pulchrum. Its life cycle begins when a primary host passes G. pulchrum eggs in its stool, whereupon an insect, such as a cockroach or dung beetle, feasts on the feces and ingests the eggs. If that infected insect is gobbled up by a primary vertebrate host, the parasite grows to adult size in two to three months.

Humans acquire the parasite the same way other animals do: By eating the wrong raw insects.

For humans, ingestion is usually accidental and food-borne. Insect parts can be present in all manner of foodstuffs, from peanut butter to pasta to ground pepper to raisins. In fact, the U.S. Department of Agriculture and the Food and Drug Administration have guidelines for the allowable number of insect parts for specific foods.

Allen doesn't know for sure how he got infected, but if it wasn't food-related it might have been from drinking well water while he was in Maine earlier conducting research. Water samples taken afterward at the research site did show the clear presence of insect parts.

He and Kerscher teamed up again to write a scholarly paper on Buddy that just appeared in the American Journal of Tropical Medicine and Hygiene under the dry title "Gongylonema pulchrum infection in a Resident of Williamsburg, Virginia, Verified by Genetic Analysis."

Kerscher jokingly suggested a catchier title: "What's in my mouth? I think it's a worm."

Allen's infection makes them both question whether others just like him are getting rebuffed by physicians or health care workers that have never heard of G. pulchrum and don't recognize the symptoms.

"It might be more common than people think," Kerscher said.

They and medical experts who studied previous cases of G. pulchrum in humans urge clinicians and other health care providers and microbiologists to be alert to the possibility of infection.

The two biologists secured a $10,000 collaboration grant from EVMS and William and Mary and are now working to devise a method to test water for the presence of the nematode.

For Allen, the big picture is twofold: education and awareness.

Now when he lectures about nematodes, parasites and infection, he offers himself up as an exhibit. As for his students, he said, "I think they're amused. And a little confused."

His message for his pre-med students is simple: "What do you do when you get unexpected data or symptoms? Just because you haven't seen it before doesn't mean your patient is crazy or doesn't have (an issue)."

And with the growing global interest in insects as a food source for humans, awareness and education become even more important.

"I'm all for feeding the world's hungry," said Allen, "but it's useful to think about the insects we're encouraging people to eat."

Chances are slim — as far as they know — that Allen is hosting another Buddy. But just in case he is, Allen said he's choosing not to take drugs to purge the nematode from his system.

"We want to find out what the prevalence of this is," he said with a smile. "To me, it's a symptom of how little we know about the world that we live in. To me, this is just a case study."

Dietrich can be reached by phone at 757-247-7892.

Would you like bugs with that?

Whether we know it or not, humans regularly eat insects and insect parts.

The U.S. Food and Drug Administration and Department of Agriculture developed guidelines on the amount of allowable insects or insect fragments in foods to maintain safety and/or a U.S. No. 1 Grade rating.

Peanut butter: 30 insect parts per 100 grams

Ground pepper: 475 insect parts per 50 grams

Golden raisins: 35 fruit fly eggs and 10 whole or equivalent insects per cup

Ketchup: 30 fruit fly eggs per 100 grams

Canned corn: 2 insect larvae per 100 grams

Blueberries: 2 maggots per 100 berries

Curry powder: 100 insect parts per 100 grams

Wheat: 1 percent of grains infested

Sesame seeds: 5 percent of seeds infested

Coffee: 10 percent of beans infested

Information from the journal Clinical Infectious Diseases and North Carolina State University.



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