How is the rectum organized and how does it work?

The rectum is nothing more than one of the main parts of the gastrointestinal tract, which is the last section of the large intestine. In an adult, the length of the rectum is 13-23 centimeters and is located in the pelvic area. To understand why hemorrhoids occur, let's look at the features of the rectum.

What is the rectum and what does it consist of?

The diameter of the rectum varies differently (2.5 – 7.5 centimeters). The rectum begins from the sigmoid colon, only at the end does it end with an opening – it is called the anal opening.

In fact, the rectum is not straight, as it has two bends, and they are located in the longitudinal plane. The very first bend is called sacral. This bend is concave toward the sacrum and ends with a convexity at the back. The second bend is called perineal, as its convexity is directed forward and it most directly represents the bend of the intestine over the coccyx.

Sections of the rectum

The rectum can be divided into three different sections. The lowest and narrowest is called the perineal, in other words, it can be called the anal canal. It is this canal that performs the function of opening outward (anus). Its length is only 2-4 centimeters.

Above the anal canal is the widest part of the rectum, its length varies from 10 to 12 centimeters, it is called the ampulla. The third section of the rectum is called "supraampullary", compared to the ampulla this section is small, only 5-6 centimeters long.

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Coccyx

The coccyx is located directly behind the rectum, and there is also the sacrum. In front of the rectum in men, in this area are the ampullae of the vas deferens, the prostate gland, the seminal vesicles and, of course, the urinary bladder. In women, in this area are the uterus and vagina. In the pictures, you can clearly see the difference in how the rectum and nearby organs are located.

Rectal protection

Several layers of protection are located on the walls of the rectum itself. As we have already said, the upper part - also supraampullar, is under the reliable protection of the peritoneum - a thin and very transparent film (shell) from the outside. The anal and ampullar canals are covered with reliable layers formed from fats and connective fibers, it does not belong to the peritoneum.

The rectum also has a middle layer, which is firmly protected by a pair of rows of muscles. The muscle fibers are on the outside (they are longitudinal). And the longitudinal muscle fibers inside contain circular fibers of the same composition, which are called the internal sphincter, also called the sphincter, and are surrounded by the external sphincter so that the fecal masses are locked and do not get out prematurely.

The sphincter fibers are securely connected to each other and are attached in a circular manner to the anus.

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Rectal mucosa

The mucous membrane is the wall of the rectum (inner wall). Incredibly thin layers of the mucous membrane are separated from the muscle layer. It is thanks to these super-thin layers that the muscular mobility of connective tissues is formed.

The epithelial cells in the form of a cylinder form the mucous membrane of the rectum. They also consist of intestinal glands, they are called mucous and goblet. They have the property of secreting a secretion in the form of mucus. It is designed to prevent wounds, scratches and other damage to the walls of the rectum when feces pass through it. Mucus also serves as a lubricant for feces, which pass through the rectum more quickly. Follicles - small lymphoid nodules - are also located in the rectum.

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Folds of the rectum

When the rectum is not filled with fecal matter, its mucous membrane is capable of forming folds - there are many of them, and they go in different directions. Two or three folds of the rectum go across, next to them are the fibers of the muscle layer, which go in a circle. They have a course in the form of a screw, and they are located in the ampulla of the rectum. There are also other folds there, which are not constant, they are longitudinal, and straighten out when the intestine is filled.

In the area of the anus, the mucous membrane forms more folds - there are from 6 to 10 of them. These folds are constant, they are called funny - anal columns. They are located near the anus and have a ring-shaped elevation at their base. This is the place where the rectal mucous membrane forms a transition to the skin of the anus - the anus.

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Blood supply system of the rectum

To have a clear idea of what causes hemorrhoids, it is important to understand how the blood supply system of the rectum works. The fact is that hemorrhoids are a disease that affects the blood vessels located in the submucosal layer of the rectum. It is because of the disruption of their structure and function that a person suffers from pain in the anus.

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The work of the five arteries

Five arteries work to start the blood flow to the rectum. Or rather, not to the rectum itself, but to it, to its submucosal layer. One of these arteries is not a paired artery, it is located at the top and is called hemorrhoidal. This artery is the end of the lower artery, which is called mesenteric.

So, the hemorrhoidal artery has an important role - it carries blood flow to the back wall of the rectum. These are the areas located above the ampulla and in the ampulla (we have already talked about them).

But there are 4 more arteries that carry blood to the rectum. They form pairs. These pairs are located on the right and left, in the middle and at the bottom of the rectum. They are the end of the hypogastric arteries.

These arteries do not work on their own - they form a single whole network of arteries that work harmoniously for the benefit of our body. The arteries are connected to each other vertically and horizontally in the walls of the rectum.

Venous system of the rectum

This is a very important system that provides the rectum with the outflow of blood running through the veins. Blood runs from smaller veins to larger ones, then runs through the arteries.

Where is the network of veins in the rectum? Its location is in the layer called the submucosal layer (we already know about it). The most solid section of the rectum is the terminal one, in which the arteries and veins do not branch out to the smallest capillaries, but stretch directly to the so-called anal columns. This causes cavernous bodies to form in the rectum, located under the mucous membrane. These bodies are also called cavernous.

When a person develops hemorrhoids, it is these cavernous bodies that swell and cause pain reflexes in a person, sometimes unbearable. This is the anatomical feature of the rectum.

Why do hemorrhoids cause lumps in the anus?

And this is exactly what the cavernous bodies or corpora cavernosa swell. They are permeated with many tiny wreaths that look like bunches of grapes. When blood accumulates in them, the "grapes" swell and increase in size. Approximately the same way the phallus swells during an erection. And then the walls of these cavernous bodies cannot withstand the influx of blood and can burst, get damaged, stretch, and, of course, hurt a lot.

Then the person complains of bleeding from the anus. To avoid or stop it, anti-inflammatory drugs are needed that will remove the inflammatory process in the cavernous bodies, and at the same time the pain. In the meantime, you need to remember that when hemorrhoids occur, the blood from the anus is not dark, but scarlet, because in the cavernous bodies it is exactly like that due to the accumulation of oxygen.

The role of the corpora cavernosa

Their role is not only to cause us trouble when hemorrhoids attack the body. No matter how long doctors have been studying the human body, they still have not fully understood what roles the cavernous bodies perform, in addition to accumulating blood. It is known that they help the sphincter to hold feces, performing an additional clamping function.

The cavernous bodies, like the appendix, are like a rudiment in the human body. They are found even in babies who have just been born, so they are needed by the body, perhaps even for roles that we do not yet know about.

Nerves of the rectum

There are many nerve endings in the rectum. Like spies who form their network, the fibers of the parasympathetic and sympathetic nervous systems are located in it. This is how nature intended it anatomically, since there are many reflexogenic zones in the rectum, and signals are transmitted through these zones from the cerebral cortex.

When a boy or girl is born, their rectum is cylindrical in shape, has no bends or ampulla, and the folds of the intestine are not very pronounced.

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Dimensions of the rectum

The length of the rectum of a newborn baby is up to 6 cm, minimum 5 cm. The anal columns of small children are very well developed. The ampulla finishes forming by the age of 8 years. And then the rectum forms bends. When a child reaches 8 years, not only bends are formed in the rectum - it generally begins to grow very quickly, lengthen and by the age of 14 becomes more than three times longer - from 15 to 18 centimeters. And the diameter of the rectum in adolescence is from 3.2 cm to 5.4 cm.

When a person gets older and reaches the age of 50-60, his rectum lengthens even more, the bends are no longer so clear, they lose their direction, and the mucous membrane of the rectum becomes much thinner. At the same time, the cavernous bodies become thin, empty, so hemorrhoids in men and women over 60-65 years old are very rare.

The work of the rectum to remove toxins

When the rectum works, it ensures the functioning of the digestive system as a whole. The rectum does the job of eliminating toxins and all unnecessary substances from the body that are no longer needed there.

When a lot of unnecessary waste accumulates in the rectum, it needs to be removed from there. And if the rectum does not work normally, these rotten and foul-smelling masses will accumulate there, poisoning the entire body. That is why it is so important for the rectum to be healthy and perform all its functions to evacuate substances unnecessary to the body.

The statistical role of the rectum

There are basic roles of the rectum. There are two basic roles. One is static, the other is dynamic. The static role of the rectum is that it will accumulate intestinal excrement and retain it.

If the feces are normal, they will be a uniform brown color. They are dense, and shades of brown may vary. Normal feces contain 30% food residues and 70% water. Food residues include intestinal epithelial cells along with dead bacteria. The daily fecal mass of a healthy person will not exceed 350 grams.

When feces accumulate in the rectum, it can become wider and the folds of the rectum (its mucous membrane) straighten out. Feces are held in the rectum by the anal sphincter because the walls of the anus are tightly compressed. The anal sphincter is designed to prevent intestinal contents from falling out on their own and gases from being released involuntarily.

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Sphincter strength

The anal sphincter is a very powerful and strong muscle. Scientific research proves that in a healthy person the sphincter strength is such that at rest it reaches 550 grams, and when it contracts, then at maximum compression this strength increases to 850 grams.

When a person suffers from hemorrhoids or other diseases of the rectum, this immediately affects the strength of the sphincter. It becomes almost four times weaker - its compression force reaches only 200 to 300 grams instead of 850. And then the contents of the intestine can come out spontaneously, and this happens during the most common everyday actions - coughing, squatting, laughing, sneezing, simple walking. In addition to feces, gases and liquid feces are not retained in the rectum, and this unpleasant process is constant - as long as the rectum is unhealthy.

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The dynamic role of the rectum

This role is no less important than the first - statistical. It is characterized by the peculiarity of the rectum to evacuate from the body what it does not need: feces, foreign substances. Namely, thanks to the dynamic function of the rectum, a person is able to defecate. This is a rather complex physiological reflex process, which Academician Pavlov wrote about. He spoke in his lectures about the fact that the need for defecation can be recognized through signals from the sensory nerves of the rectum.

This means that when the walls of the rectum are irritated by the fecal matter that has accumulated there, a signal is sent through the reflex endings that it is time to evacuate it from the rectum.

Sometimes it happens that a person feels the urge to evacuate feces from the rectum when it is empty. This means that there are problems with its functioning. For example, with diseases such as ulcerative colitis, hemorrhoids, infections that have penetrated the intestines.

Muscles involved in defecation

Muscle fibers play the most direct role in the process of defecation. These muscle fibers are located on the walls of the intestine. They are joined by the abdominal muscles, which we so stubbornly do not want to pump up. And in vain: this would significantly strengthen the body, since human health depends on the success of the defecation process.

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How does defecation occur?

When the process of defecation begins, a person inhales deeply, this closes the glottis, and the sphincter of the anus weakens its pressure, relaxes, while the abdominal press tenses. If the abdominal press is weak, a person will not be able to perform a normal act of defecation, strains for a long time, feces from the rectum may go weakly.

When a person takes a deep breath, the diaphragm muscle moves down, causing the abdominal cavity to contract and decrease in volume. At this time, a lot of pressure is created in the abdominal cavity, and feces are ejected through the anus. This pressure is so strong that it reaches 220 mm H2O pressure, which is more than one and a half times higher than the level of arterial pressure created by the blood flow.

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Patterns of defecation

The process of defecation, like any other processes occurring in the body, has its own patterns. Scientists have tracked these patterns and found out that there are two types of defecation: one-stage and two-stage.

During a single-stage defecation, the rectum is able to throw out its contents in one go. If defecation is two-stage, then the feces are thrown out by the intestines not in one go, but in parts. This can take from three to seven minutes. So, with a two-stage ejection of feces, a person is forced to stay in the toilet for more than seven minutes, since during the first act of ejection of feces, he has a feeling that the process is not finished.

Both the first and second types of defecation are normal and characteristic of humans - they are simply anatomical features that do not pose a health hazard, given their contractile properties.

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Prolonged defecation

It happens that a person cannot defecate for more than 15 minutes. Then the process drags on for up to half an hour. All this time, the person tries to forcefully push the feces out of the rectum.

Instead of waiting for the next contraction of the intestinal walls and pushing out the feces in a period of 7-15 minutes, a person begins to panic and push them out, straining. And then the constant tension in the abdominal press causes overstrain in the veins of the rectum, in particular - in the already familiar cavernous (cavernous) bodies.

This causes hemorrhoids, as the cavernous bodies swell and become inflamed. The anus may also develop cracks and inflammation, and the rectum may begin to fall out from fruitless attempts to strain it.

Therefore, if the process of defecation is significantly slowed down, which is accompanied by pain in the anus, you should consult a doctor. A proctologist can help you.

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Statistics of types of defecation

Research shows that up to 70% of people experience one-stage defecation. Then up to 25% of people experience two-stage defecation – there is no other way to put it. The rest of the people have mixed defecation.

There are exercises that allow a person to achieve a single, most convenient type of defecation for them. You need to consult a proctologist about how to do them.

As for patients with hemorrhoids, up to 90% of them suffer from the fact that they have a two-stage type of defecation. They need to be especially careful during bowel movements and use the natural processes inherent in the rectum, that is, the time of its contraction.

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Why self-medication is dangerous

Often a person does not pay attention to the type of his defecation and considers it just a simple inconvenience, not suspecting that he is causing irreparable harm to his body.

If a person suffers from constipation, if he develops hemorrhoids, he should not self-medicate, because the rectum, if the methods are chosen incorrectly, can become covered with cracks from the inside or outside, bleeding can occur from the swollen cavernous bodies, there can be a danger of retention of feces in the rectum and poisoning of the body with toxins. You should not neglect these symptoms and go to the clinic at the first signs of pain and discomfort in the rectum.