Small Intestine and Large Intestine

Small intestine

Basically, the stomach is connected to the large intestine by a long, narrow tube that is folded or coiled. It is responsible for digesting and absorbing food. The organ measures approximately 6.7 to 7.6 meters (22 to 25 feet) long, is highly convoluted and is located centrally and below the abdominal cavity. The mesentery is a thin membrane that supports and suspends the intestines. In addition to its area of fat, the mesentery contains a web of blood vessels that aid in the retention of heat in the organs. There are two divisions of the autonomic nervous system that control the small intestine: parasympathetic nerves trigger muscle contractions that move food along (peristalsis), and sympathetic nerves halt intestinal contractions.

According to tradition, the small intestine is divided into three sections: the jejunum, duodenum, and ileum. Even though they are continuous tubes, they exhibit certain characteristics that differentiate them, but cannot be distinguished from one another. A small, hollow tube along the middle of the stomach called the duodenum is 23 to 28 cm (9 to 11 inches) in length, has the largest diameter, and does not have mesentery support. It is the liver, gallbladder, and pancreas that provide juices to the duodenum which neutralize stomach acids and aid in digestion of proteins, carbohydrates, and fats.

Around two-fifths of the remaining tract is located in the jejunum, in the center of the abdomen. Its deep red color results from its extensive blood supply; its peristaltic movement is rapid and vigorous; and the mesentery that supports the jejunum contains little fat. Its deep red color results from its extensive blood supply; its peristaltic movement is rapid and vigorous; and the mesentery that supports the jejunum contains little fat. The walls are thinner and narrower in this part, it has a more limited blood supply, the peristaltic movements are slower, and it has larger fat areas than in the previous part.

Higher vertebrates have transverse loops along their small intestines known as plicae circulares. There are finger-like projections inside the cavity called villi. The surface area of these structures is greatly increased, as is the surface area of the secreting and absorbing cells. Small intestine walls are lined with microscopic glands. Intestinal walls are protected by runner secretions found within the submucosa of the duodenum. In addition to serving as an outflow port for Brunner glands and providing surface-membrane cells to replace shed cells shed from villi, Liebkühn glands exist in a mucous membrane and secrete digestive enzymes.

By performing rhythmic segmentation movements along the small intestine, digestive enzymes from the pancreas, liver, and intestinal walls are combined with digestive materials as they move through the small intestine, encouraging them to contact the absorbent surface. In the small intestine, appetizer waves transport digestive substances, while rhythmic segmentation breaks up these substances, mixes them thoroughly with digestive enzymes produced by the pancreas, liver, and intestinal wall, and then introduces them to the absorbent surface.

Large intestine

About 1.5 meters (five feet) long is the length of the large intestine. Large intestines are much broader than small intestines, and they travel straighter through the abdomen than small intestines. Water and salts are absorbed from undigestible material in the large intestine, and waste products are eliminated. Almost all digestion and absorption of food has already taken place by the time you reach your large intestine.Fiber (plant matter) is mainly left behind, along with dead cells shedding from your intestinal lining, salt, bile pigments (which give the material its color), and water. This mixture is consumed by bacteria in the large intestine. Besides producing valuable vitamins that are absorbed into your bloodstream, these helpful bacteria also help digest fiber. You have three main parts of the large intestine:

Cecum - A pouch-shaped section of your large intestine occupies the first two inches of your large intestine. The colon receives and passes the digested liquid from the ileum.

Colon - The large intestine is divided into this section; you may have heard about the colon alone. It is also the primary site where water is reabsorbed, and salts are absorbed when necessary. There are four parts to the colon:

Ascending colon - Under the right lower end of the liver, this part of the colon moves any undigested matter up from the cecum using muscle contractions.

Transverse colon - The food passes from left to right across the front of your abdomen, just under the stomach, in this second part of your colon.

Desending colon - From just near your spleen, the third part of your colon pushes towards the left side of your abdomen.

Sigmoid colon - The last part of your colon is the S-shaped section that curves inward and empties into your rectum.

Rectum - Approximately 2.5 to 4 cm is the length of the final portion of the digestive tract. The rectum expands as waste is leftover, until you make a trip to the bathroom. Once it reaches this point, it will be ready to be emptied through your anus.

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