Intestines

• Main article: Human body
• Main article: Gastrointestinal tract (GI)

Small intestine 5-6 meters long

In the small intestine, nutrients are absorbed and then spread through blood vessels throughout the body. It is about 5-6 meters long. There are villi on the intestinal mucosa to digest and absorb nutrients. They increase the suction surface and are well supplied with blood.

The small intestine is divided into duodenum, jejunum, and ileum.

Duodenum

The duodenum is C-shaped and 25 cm long. In the wall of the duodenum there are Fater nipples. It receives bile, which is produced by the liver, and pancreatic juice with enzymes from the pancreas to break down food.

Jejunum and ileus

The upper half (about 2/5) of the small intestine is called the jejunum. The rest (3/5) is ileum. There are some features that make it possible to distinguish the jejunum from the ileum. The jejunum is wider and has a thicker wall. It is located in the umbilical region. The ileum is thinner, has a smaller diameter, located in the lower part of the abdomen. It has blood supply in short numerous vessels.

Large intestine about 2 meters long

The final part of the gastrointestinal tract is the large intestine, where the absorption of water and the formation of feces, the rectum and the anal opening occur. The length of the large intestine is about 2 meters. There are no villi in the colon and it is not involved in digestion. The colon has gaustras (circular protrusions), longitudinal muscle bands, and omentum processes.

The cecum is the first part of the colon. It begins with the Bauginium Damper (ileocecal valve), which separates the small and large intestine. The appendix departs from the cecum - a worm-like process. Its length is on average 8-15 cm, diameter 1 cm. The appendix is rich in lymphoid tissue, which is part of the body's protective system. Next comes the colon, which is divided into ascending, transverse, descending and sigmoid.

Rectum

The rectum serves as a reservoir for feces. Despite its name, the rectum has two bends. The mucosa gathers into longitudinal folds that are easily smoothed when the intestinal walls are stretched.

The rectum is 12 cm long and consists of an ampoule and an anal canal with an anal opening. The rectal ampoule is divided into 3 parts: upper, middle and lower. Behind the rectum are the sacrum and coccyx. In front of men - the prostate gland, in women - the uterus and vagina.

Leading role in the immune system

The gut is our main immune system, not the second, as they say, but the most important.

First, because it contains more immune cells than the rest of the organs that make up this system, such as the thymus or spleen.

Secondly, in the intestines there is the closest contact with what we eat and what we meet in the environment, including bacteria.

Bacteria

Usually bacteria appear to us as pests, but the proportion of those that cause food poisoning is relatively small.

At birth, the gastrointestinal tract of the newborn is sterile. In the first hours of its life, it is populated by various microorganisms.

As the body grows and the digestive system improves, a normal microflora forms.

In a healthy adult, approximately 300-500 bacterial species live in the colon at any given moment.

The upper parts of the digestive system are hostile to microorganisms: the stomach releases hydrochloric acid, and the small intestine is full of digestive enzymes; however, the colon provides an excellent habitat for microorganisms.

By the time the food got here, the enzymes had almost completed their work and most of the nutrients have been absorbed, but bacteria have their own enzymes that allow them to break down what our bodies have not coped with, so we get even more nutrients from food (mostly in the form of fatty acids).

The gut and the bacteria in it constantly communicate chemically. The composition of bacteria has a noticeable effect on various organs, including even the brain.

How does our gut know which bacteria are good and which are bad?

This is a very difficult question, and it depends on the receptors. Toll-like receptors recognize so-called molecular models of bacteria.

Pathogenic bacteria have other models, thanks to which cells determine that such a bacterium is different from the one that should inhabit us.

They are resistant to "friends" (good bacteria) and live with them in symbiosis. The presence of an "enemy" in turn causes alarm and activates the immune system.

Bacteriophages

Main article: Bacteriophages

Bacteriophages are natural limiters of the growth of the bacterial population in nature and in the human body.

Vermicular movement

Peristalsis is a wave-like contraction of the walls of hollow tubular organs.

Such a process constantly occurs in our intestines and contributes to the promotion of food.

Diagnosis of intestinal microflora

2023

Type of gut bacteria that causes Parkinson's disease identified

In early May 2023, Finnish specialists from the University of Helsinki announced a discovery that in the future could help treat Parkinson's disease, a slowly progressive neurodegenerative disease that affects mainly people of the older age group. Read more here.

In Moscow, began to produce express tests for the diagnosis of intestinal microflora children

The capital company has launched the production of medical tests that allow diagnosing the intestinal microbiota of children in three hours, Deputy Mayor of Moscow for Economic Policy and Property and Land Relations Vladimir Efimov said on February 15, 2023. Read more here.

Microbiome

Main article: Microbiome

Bowel diseases

Inflammatory Bowel Disease (IBD)

Main article: Inflammatory Bowel Disease (IBD)

Bowel cancer

Main article: Bowel cancer (colorectal cancer)

Technologies

2022: Smart capsule created for permanent bowel exam

On December 1, 2022, it became known that researchers from the University of California, San Diego (USA) developed an advanced swallowed capsule for monitoring the small intestine for a long time. Read more here.

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