For most of you who still read this GERMS post, you may feel that this starts to get boring, but for some of you, I hope you still find it interesting, as I will continue to share as much knowledge as I can, without making you falling asleep. Let's talk more about germs, particularly about birth, infants as well as H. Pylori.
Let's see. Like the colonization of the mouth and the skin, that of the human digestive tract, home to approximately 99% of the body's microflora, begins during birth, starting with the lactobacilli encountered in the birth canal. As the baby's head crowns, it compreses the mother's rectum, pushing out a small amount of stool. This head to anus position ensures that, of all billions of microbes, the baby will meet in its first day of life, the first will be those to which its mother immune system has already developed protective antibodies. Bear in mind, that a temporary supply of these antibodies have already passed to the fetus through the placenta. A chaser of breast milk delivers the second wave, millions of bifidobacteria.
All incoming microbes, before they reach the intestines, must pass through the antechamber of the baby's stomach. In the stomachs of the older children and adults, high levels of hydrochloric acid present a microbe killing barrier. But, acid secretion doesn't begin until around 3 months of age, building gradually to adult levels over several years. This delay leaves open a welcoming door for the colonization of the stomach and intestinal tract during early life. Say, for example, a baby meets the stomach bug called H.Pylori during this period. For some people who known of this bug, he or she would know how destructive and 'durable' it is.
Children typically do so on the hands or lips of someone already colonized. Once swallowed, this bacterium drills into the mucus layer that will protect the stomach from the hydrochloric acid bath to come. As the acid producing cells of the stomach mature, some strains of H.Pylori inject proteins that direct the cells to lower the acidity to levels that are more tolerable to this bug, but still acidic enough to kill most of other kinds of microbes. In this way, H.Pylori has maintained a virtual monopoly over the human stomach for over decades. The strain H.Pylori carried by a particular family or population can even be trace ancestry as far back as the ancient migration patterns that began when Homo Sapiens first hiked out of Africa!
H.Pylori, can triggers inflammation serious enough to produce gastric ulcers and stomach cancer in later life. In any case, H.Pylori is rapidly becoming extinct in the Western world, possibly leaving the stomach open for colonization by some other bugs. proceeding past the antechamber of the stomach, surviving microbes enter the switchback of the small intestine, where a forest of fingerlike extensions, called villi, maximize the surface area through which nutrients can enter thebloodstream. The low acidity or low pH, of the small intestine proves ideal doe bacterial growth.
The small intestine is where incoming microbes most directly engage infant's dormant immune system. In places, the villi part to reveal barren hillsides, their surfaces a mosaic of oddly flattened and pitted cells. It's called the Peyer's patches, these domelike structures overlie the immune system's most important training academies. The pits on the surface of these flattened cells are pockets that continually snag passing bacteria, both live and dead. Like revolving doors, these pockets migrate to the cells inner surface, ushering their microbial passengers into the lymph tissues.
The internal structure of the Peyer's patch resembles that of the lymph nodes that will mature in the infant's neck, groin and armpit. But, if lymph nodes resemble war rooms where immune system cells can learn what to attack, the lymph tissue of the Peyer's patch resembles a diplomatic center where incoming microbes get the benefit of the doubt, where they are presumed 'friendly' until proven other wise.
Well, if one say that the immune system learns to ignore the intestinal bacteria, however, would be wrong. Rather then inducing a microbe-killing inflammation, the interaction of the Peyer's patch triggers the production of an abundance of the antibody known as immunoglobulin A, or IgA. Like all antibodies, each IgA attaches to a specific target, in this case, a particular kind of intestinal bacteria. Whoever studied medical or health science, this would sound very familiar to you, unless, you did not pay attention during Immunology lectures. To meet and greet inside the neutral territory of the Peyer's patch, also leads to the proliferation of the T and B cells that will marshal an attack against these same bacteria should they turn up in forbidden territory, such as the blood.
So, an infant's immature immune system learns to tolerate swallowed bacteria while warily keeping them at a distance. over the course of childhood, the numbers of Peyer's patches lining the small intestine dwindles from several hundred to around thirty? Not entirely sure, but I think that's the approximated figure I could still remember. This remnant group of Peyer's patches clusters along the final segment of the small intestine just before it opens into the expansive bacterial holding chamber of the colon. Within this remnant, a much reduced diplomatic corps of immune cells continues to monitor the daily passage of millions of microbes, recognizing the vast majority as normal and worthy of tolerance.
Once they have passed through the forceful contractions and microbe snagging cells of the small intestine, bacteria enter the settling tank of the large intestine. Though it is sterile at birth, it will become the microbial rain forest of the human body. At the end of the vaginally delivered baby's first day of life, the scattering of bacteria in his poop reflects that of his mother vaginal and intestinal tract.
By contrast, that of the cesarean-born baby contains a more random assortment of microbes from the hands of the birth attendants and the general hospital environment. Whatever the method of delivery, by the third day , a breast fed infant es excreting a near monoculture of bifidobacteria, which continues to predominate until the introduction of solid food. Bear in mind that the intestinal flora of a 'formula-fed' infant also contains bifidobacteria, but the source is unknown, and far much smaller numbers and as a small part of an unstable mixture of other mibrobes. So parents, this is a very important point to take note.
In the intestine, as on the baby's skin and in its mouth, the bifidobacteria discourage the growth of potential troublemakers such as staph and help to select the first permanent resident. Studies also show that an abundance of intestinal bifidobacteria boosts the level of protective antibodies in a baby's blood, antibodies that target not only problematic bacteria but many kinds of diarheaa inducing gastrointestinal viruses. This phenomenon may also explain why in Third World countries with poor water sanitation, the mortality rates of breast fed infants are as much as six times lower then formula fed babies during the first six months of life, regardless the family income or education level.
The first wave of intestinal microbes also triggers the maturation of the colon's lining. Underlying blood vessels extend to the lining's surface and there form the dense network of tiny capillaries needed both to keep it healthy and to carry away the nutrients liberated by resident bacteria. At the same time, the first touch of bacteria awakens millions of intestinal stem cells. Once activated, these cells begin endlessly dividing, and their proliferation continually refreshes the intestinal lining's delicate layer of surface cells.
The surface cells, in turn begin shedding at a rate of several billion cells per day! This replacement renders the intestinal tract resilient to the kind of injuries that inevitably occur when a child starts eating solid food, with its abundance of natural toxins as well as the occasional sharp object or disease causing microbe.
Folks, I know this is one pretty darn boring read. A lot of science and too much of germs stuff. Well, if you are into microorganisms' world, you might like what you read here. Till then, stay tuned.
The internal structure of the Peyer's patch resembles that of the lymph nodes that will mature in the infant's neck, groin and armpit. But, if lymph nodes resemble war rooms where immune system cells can learn what to attack, the lymph tissue of the Peyer's patch resembles a diplomatic center where incoming microbes get the benefit of the doubt, where they are presumed 'friendly' until proven other wise.
Well, if one say that the immune system learns to ignore the intestinal bacteria, however, would be wrong. Rather then inducing a microbe-killing inflammation, the interaction of the Peyer's patch triggers the production of an abundance of the antibody known as immunoglobulin A, or IgA. Like all antibodies, each IgA attaches to a specific target, in this case, a particular kind of intestinal bacteria. Whoever studied medical or health science, this would sound very familiar to you, unless, you did not pay attention during Immunology lectures. To meet and greet inside the neutral territory of the Peyer's patch, also leads to the proliferation of the T and B cells that will marshal an attack against these same bacteria should they turn up in forbidden territory, such as the blood.
So, an infant's immature immune system learns to tolerate swallowed bacteria while warily keeping them at a distance. over the course of childhood, the numbers of Peyer's patches lining the small intestine dwindles from several hundred to around thirty? Not entirely sure, but I think that's the approximated figure I could still remember. This remnant group of Peyer's patches clusters along the final segment of the small intestine just before it opens into the expansive bacterial holding chamber of the colon. Within this remnant, a much reduced diplomatic corps of immune cells continues to monitor the daily passage of millions of microbes, recognizing the vast majority as normal and worthy of tolerance.
Once they have passed through the forceful contractions and microbe snagging cells of the small intestine, bacteria enter the settling tank of the large intestine. Though it is sterile at birth, it will become the microbial rain forest of the human body. At the end of the vaginally delivered baby's first day of life, the scattering of bacteria in his poop reflects that of his mother vaginal and intestinal tract.
By contrast, that of the cesarean-born baby contains a more random assortment of microbes from the hands of the birth attendants and the general hospital environment. Whatever the method of delivery, by the third day , a breast fed infant es excreting a near monoculture of bifidobacteria, which continues to predominate until the introduction of solid food. Bear in mind that the intestinal flora of a 'formula-fed' infant also contains bifidobacteria, but the source is unknown, and far much smaller numbers and as a small part of an unstable mixture of other mibrobes. So parents, this is a very important point to take note.
In the intestine, as on the baby's skin and in its mouth, the bifidobacteria discourage the growth of potential troublemakers such as staph and help to select the first permanent resident. Studies also show that an abundance of intestinal bifidobacteria boosts the level of protective antibodies in a baby's blood, antibodies that target not only problematic bacteria but many kinds of diarheaa inducing gastrointestinal viruses. This phenomenon may also explain why in Third World countries with poor water sanitation, the mortality rates of breast fed infants are as much as six times lower then formula fed babies during the first six months of life, regardless the family income or education level.
The first wave of intestinal microbes also triggers the maturation of the colon's lining. Underlying blood vessels extend to the lining's surface and there form the dense network of tiny capillaries needed both to keep it healthy and to carry away the nutrients liberated by resident bacteria. At the same time, the first touch of bacteria awakens millions of intestinal stem cells. Once activated, these cells begin endlessly dividing, and their proliferation continually refreshes the intestinal lining's delicate layer of surface cells.
The surface cells, in turn begin shedding at a rate of several billion cells per day! This replacement renders the intestinal tract resilient to the kind of injuries that inevitably occur when a child starts eating solid food, with its abundance of natural toxins as well as the occasional sharp object or disease causing microbe.
Folks, I know this is one pretty darn boring read. A lot of science and too much of germs stuff. Well, if you are into microorganisms' world, you might like what you read here. Till then, stay tuned.
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