Small Intestine Function, Location, Parts, Diseases & Facts
What is Small Intestine?
How does your body benefit from the food you eat? Which “small” part of the digestive system does a "big" job of handling most of the digestion process? Where does most of the absorption of the nutrients take place? It is small intestine which, though small in diameter, is the longest part of the gastrointestinal system. “Small Bowel” is one of the commonly used small intestine names.
The organ is responsible for the absorption of over 90% of nutrients from the food. According to the MUSC Digestive Disease Center, it absorbs more than 95% of the ingested proteins and carbohydrates. 
The small intestine starts from the pyloric sphincter at the lower end of the stomach and continues to the beginning of large intestine at the ileocecal junction. It is as big as your middle finger. In other words, it measures around 1 inch in diameter.
Table of Contents
- What Is Small Intestine?
- Small Intestine Location
- How Food Moves Along Digestive Tract
- Small Intestine vs Large Intestine
- Small Intestine Parts
- Small Intestine Histology
- Small Intestine Function in Digestive System
- Interesting Small Intestine Facts
- Small Intestine Diseases
Small bowel is the longest part of the digestive system. However, different sources give different measurement for the small intestine length. For example, the Cleveland Clinic suggests its length to be 22 feet.  According to MUSC Digestive Disease Center, the length may vary between 20 and 25 feet.  A Wikipedia article suggests the maximum length to be over 34 feet.  Finally, the Inner Body puts its size to be just 10 feet. 
The part of the digestive tract between stomach and colon performs several different jobs of vital importance for the body. However, the primary small intestine function is to absorb the nutrients from the food for use in the body. Its other jobs include physical breakdown, chemical digestion, secretion of mucus and hormones, packaging of waste products, and so on.
Several diseases of mild and serious nature affect this organ. The small intestine diseases have been grouped into many categories, including obstructive disorders, infectious diseases, cancers and genetic conditions. Any of these conditions can adversely affect the process of digestion and absorption of nutrients. However, by taking care of diet, you can keep this organ in healthy condition.
Just read on to find useful information and interesting facts about small bowel.
Small Intestine Location
It is easy to find small intestine location in the body. Stretching from the stomach to the cecum of large intestine, the small bowel is located within the central and lower abdominal area. How does twenty feet length of the bowel fit into such a small space? Actually, it coils around several times to fit into a small space in the lower abdominal area.
In the small intestine diagram, it is visible between the ascending, transverse and descending part of the colon. It is located more centrally while the large bowel is more towards the periphery. The latter has the diameter of around 2.5 inches against 1 inch lumen of the small intestine.
How Food Moves Along Digestive Tract
The journey of food along the alimentary canal starts at the mouth. Your mouth does the job of grinding, masticating and also partly digesting the food. The enzymes in saliva carry out the digestion of especially the carbohydrate component of the food.
After partial digestion, the semi-solid mass of food enters the esophagus and passes through it with the help of the peristaltic movements. The peristalsis is so powerful that it will move the food towards the stomach even while you are doing headstand! The cardiac sphincter, at the end of esophagus, regulates the movement of food from esophagus to stomach. It also prevents the acidic stomach contents from splashing back into the food pipe.
A hollow sac or container, the stomach breaks the food down both physically and chemically with the help of muscular contractions and acidic and enzymatic secretions. The acidic secretions also serve to kill the harmful microbes and germs which enter the stomach with food. After partial digestion in stomach, the food is emptied into the small intestine through the pyloric sphincter.
Small intestine is one of the most important organs of the gastrointestinal system. It is the longest and, probably, the narrowest part of your digestive system. Before entering the large intestine, the food passes through three segments of the bowel – duodenum, jejunum and ileum.
The small bowel joins the colon at the point of ileocecal junction. The large bowel not only serves as the temporary storage of indigestible matter but also a site for the absorption of water and leftover nutrients from the food.
The digestive waste leaves the body via anus in the process of defecation.
Small Intestine vs Large Intestine
The intestines are the hollow muscular tubes, running from the stomach till the anus. As you already know, one of them is called ‘small intestine’ and the other ‘large intestine’ or ‘colon’.
Moving from the mouth to the anus, the small bowel runs from the pyloric sphincter at the end of the stomach till the ileocecal junction. On the other hand, the colon begins at the ileocecal junction and ends at the anus.
The words “small” and “large” attached to the name of intestine can be the source of confusion. Let’s clear that confusion now. The small bowel is small not in terms of length but for its narrow lumen. In fact, it forms the longest part of the gastrointestinal system.
On the other hand, the large bowel is not large in terms of length. Actually, it has more than twice the diameter of the small bowel.
The main job of small intestine is to absorb nutrients from the digested food while the colon serves as a temporary storage for the digestive wastes before their discharge out of the body.
Small Intestine Parts
There are three major small intestine parts, namely, duodenum, jejunum and ileum. Moving from the stomach to the large intestine, they appear in the following sequence:
Duodenum ⇒ Jejunum ⇒ Ileum
These segments of the bowel also increase in length in the same sequence. It means duodenum is the smallest and the ileum the largest part. Overall length, however, may be greater in tall persons. It also increases when it is empty and after the individual dies. 
There is division of labor among different segments. In other words, each of the small intestine parts must perform a specific assigned task.
Here follows a brief overview of each of these parts.
The first and shortest segment of the small bowel, duodenum connects the stomach to the jejunum. This C-shaped hollow tube measures around a foot in length. Duodenum receives food from the stomach in the form of chyme and mixes it with bile juice and the pancreatic secretions. It neutralizes the partially digested food with the help of alkaline mucus containing a high concentration of bicarbonate ions. The mucus is secreted by the Brunner’s glands present only in the duodenum. 
Sometimes, it may reach the length of 15 inches. 
The enzymatic secretions help in the digestion of carbohydrates, proteins and fats. So, the process of chemical digestion that started in mouth gets completed here. It also prepares food for absorption in jejunum.
You can distinguish duodenum into four different parts. These are:
The Superior Part
The superior part is the continuation from the pylorus and lies posterior to all other segments. It lies at the vertebral level of L1. About 2 cm in length, the superior part of duodenum is mobile and ends at the superior duodenal flexure.
The Descending Part
The descending part starts at the superior duodenal flexure and descends to reach below L3 level of vertebral body. It ends at the inferior duodenal flexure. The common bile duct and pancreatic duct are attached to the descending section of the bowel at the point of major duodenal papilla.
Through the bile and pancreatic ducts, the intestine receives bile juice and pancreatic secretions.
The Horizontal Part
The third part of duodenum is also called the inferior part or the horizontal part. Beginning at the inferior duodenal flexure, it passes in front of the inferior vena cava and the abdominal aorta.
The Ascending Part
The fourth and last part of the duodenum passes upward to reach the duodenojejunal flexure where it joins with the jejunum. Lying at the vertebral level L2, it may pass directly on top of the aorta.
Jejunum is the second or middle part of the small intestine. In terms of length, it is longer than duodenum and shorter than ileum. Measuring around 8 feet, the duodenum is as many as 8 times longer than the duodenum.
While duodenum carries out and completes the chemical digestion, jejunum is the principle site for the absorption of nutrients from the digested food. This is the place where over 90% absorption of the foodstuffs takes place.
Though villi or finger-like projections are present across all segments of small bowel, they are longer and more active in jejunum. The epithelial cells, lining the villi, also have microvilli. The folds in the epithelium, villi and microvilli collectively contribute to incredibly increase the surface area for absorption.
Nutrients move across the epithelium of jejunum and ileum with the help of active or passive transport. Small peptides, amino acids, vitamins and glucose are actively transported. Fructose, on the other hand, moves through the passive transport.
The pH is between 7 and 9 which means the medium is neutral or slightly alkaline. The suspension of the jejunum by mesentery in the abdominal area renders it sufficient mobility. Meanwhile, the circular and longitudinal layers of smooth muscles in the intestinal wall generate peristaltic movements. Peristalsis helps in the pushing of foodstuffs towards the posterior end of the gastrointestinal tract.
The third and longest segment of small bowel, ileum runs for the length of 12 feet, accounting for three-fifths the length of the small bowel. Continuous with the jejunum, it ends at the ileocecal valve which separates it from the cecum. Mesentery, a fold of the serous membrane, suspends ileum from the abdominal wall.
The layers of longitudinal and smooth muscles in the ileal wall are thinner than those of other parts of small intestine. So, the peristaltic contractions are slower. Also its lining is less permeable than that of the preceding small intestine parts.
Regarding its role in digestive system, the ileum contains receptors for absorption of vitamin B12 and bile salts. Meanwhile, it also absorbs the leftover nutrients from the digested food. Ileum absorbs about 95% of the conjugated bile salts from the intestinal contents.
Hans Conrad Peyer, a Swiss anatomist, discovered bundles or patches of lymphatic cells in ileum. These patches are named after him as Peyer’s patches. You can see them by the human naked eye as elongated thickened areas without villi. Every individual has 30 to 40 such patches in their intestine.
Peyer’s patches have B and T cells similar to those found in the peripheral lymph nodes. So, they are said to play a role in the generation of immunologic response in the body.
Small Intestine Histology
The small intestine histology is both complex and interesting. The small intestine wall is made of four different layers. Each of these layers is both structurally and functionally different from the others.
For example, mucosa serves as a site for secretion and absorption. The smooth muscle layer (muscularis externa), on the other hand, generates waves of peristaltic movements for pushing the foodstuffs along the lumen.
The four layers of small intestine wall are: mucosa, submucosa, muscularis externa and serosa. Here is precise description of each of these layers.
Mucosa is the innermost layer, lining the lumen of the bowel. This layer is responsible for secreting mucus and other substances into the lumen and absorbing useful nutrients from the luminal contents. The mucosa is distinguishable into three sublayers of epithelium, lamina propria and muscularis mucosae.
Forming first part of the intestinal mucosal layer, the epithelium consists of single layer of cells. The laminal propria and muscularis mucosae provide support and articulation to the epithelium.
It is specialized to provide a large surface area for the absorption of nutrients. Circular folds, villi and microvilli are three important anatomical factors that increase the absorptive surface 600 times beyond that of a cylindrical tube.
The circular folds not only increase the surface area for absorption but also slow down the passage of luminal contents.
The small finger-like projections of villi increase the mucosal surface area tenfold. Meanwhile, the apical surface of enterocytes is covered by numerous microscopic finger-like projections, called microvilli, which further increase the surface area for absorption twentyfold.
The single-cell thick epithelium of small intestine contains six different types of cell. These are:
Nutrient Absorbing Cells: Nutrient absorbing cells or enterocytes are the most abundant cells in the epithelium. They absorb the products of digestion including peptides, amino acids, simple sugars, lipids, vitamins, ions and water.
Protective Cells: The goblet cells play protective role by secreting mucus and depositing it against the epithelium. So, the harmful substances in the luminal content do not harm the lumen.
Hormone Secreting Cells: The epithelial wall also secretes different gastrointestinal hormones with the help of enteroendocrine cells present in it. These hormones include secretin, enteroglucagon and pancreozymin, etc.
Anti-microbial Cells: There are Paneth cells in the mucosa which secrete antimicrobial peptides, such as human beta-defensin. As the name suggests, the antimicrobial peptides kill harmful microbes in the luminal contents.
Immune Cells: The lymphocytes in the Peyer’s patches and Tuft cells, present in the intestinal epithelium, play a part in the immune response.
Lying beneath the epithelium, lamina propria is a thin layer of loose connective tissue. Its job is to provide nutrition and support to epithelium. At the same time, lamina propria also serves as the means to bind the epithelium to the underlying tissue.
In the small intestine, the lamina propria contains capillaries, lymphoid tissue and a central lymph vessel. It is rich in the immune cells, called lymphocytes.
The glands of this layer secrete mucus and serous secretions which enter the lumen through ducts opening on to mucosal epithelium.
Located external to the lamina propria, the muscularis mucosae is the third sublayer of mucosa. It separate lamina propria from the submucosa.
Several thin layers of smooth muscle fibers combine to form the muscularis mucosae. These muscle fibers are oriented in different directions to enhance contact between the contents of the lumen and the epithelium.
Submucosa is a thin layer of connective tissue that lies beneath mucosa to provide support and connect it with the muscular layer below. The nerves, lymph vessels and small intestine blood supply run through this region to reach mucosa.
The muscularis externa is composed of two layers of smooth muscle. The inner layer is circular while the outer one is longitudinal. The coordinated movement of muscle fibers produces a wave-like motion, called peristalsis. The peristaltic contractions push the luminal content along the lumen towards the posterior end of the digestive tract.
The serosa or serous membrane secretes the serous fluid. It consists of two layers of mesothelium, that is, the visceral membrane (inner layer) and the parietal layer (outer layer). There is a connective tissue between the visceral membrane and the parietal layer.
The serous fluid from the serosa has a consistency similar to thin mucous. It serves as a lubricant and reduces friction from muscle movements.
Small Intestine Function in Digestive System
A long, hollow, narrow and folded tube, the small intestine is the principle organ of the digestive system. It is the site for most digestion and absorption of food you eat. Apart from digestion and absorption, it performs several other tasks as well.
Some of the important small intestine functions are discussed below:
The semi-digested food or chyme, coming from the stomach, is highly acidic in nature. It needs to be neutralized for the optimum activity of intestinal enzymes.
How is acidic chyme neutralized in the duodenum of small intestine? Duodenum, the first segment of small bowel, secretes a hormone, secretin. This hormone causes the pancreas secrete large amounts of sodium bicarbonate. Sodium bicarbonate raises the pH of chyme from 2 to 7. Meanwhile, the mucus and bile juice also has a neutralizing effect.
Protection from Acids
The pH of the acidic chyme, expelled from the stomach to the small intestine, is 2. It can damage the wall of small bowel. Now it is the job of small intestine to protect itself from such damage.
The goblet cells in the intestinal epithelium secrete mucus which forms a layer to save the intestinal wall from luminal contents.
Protection from Microbes
There are anti-microbial cells (Paneth cells) in the epithelial wall of the bowel. The Paneth cells secrete anti-microbial peptides which kill harmful microbes in the luminal contents.
Emulsification of Fats
As chyme enters the duodenum from stomach, bile is released by the gallbladder. The bile juice emulsifies and breaks down the fats into small particles, thus aiding in the mechanical digestion of fats.
The contractions of circular muscles in the intestinal wall facilitate the mechanical breakdown of the food. Through these contractions, the foodstuffs are mixed with secretions from pancreas and gallbladder. Meanwhile, the large food particles reduce to smaller ones.
Duodenum not only mechanically breaks down the food but also digests it chemically. The secretions of liver, pancreas and bowel help in the chemical breakdown of the carbohydrates, lipids and proteins.
Absorption of Nutrients
Small intestine plays a key role in the absorption. In fact, it absorbs about 95% of all the useful substances from the food, including ions, amino acids, glucose, small peptides, lipids, water, vitamins, fructose, iron and bile salts.
Absorption of iron takes place in the duodenum and the terminal ileum takes up bile salts and vitamin B12. The remaining nutrients are absorbed by jejunum through either diffusion or active transport.
Among other crucial functions, the small intestine also helps in the bowel movements to expel digestive waste towards the posterior end of the digestive tract for its ultimate removal out of the body. The coordinated contractions of circular and longitudinal smooth muscle fibers in the intestinal wall not only help in the mixing of foodstuffs with secretions but also facilitate bowel movements along the lumen.
Role in Immunity
The small intestine also supports your body’s immune system. The probiotic gut flora has a positive and supportive effect on the defense system of your body. The ileum contains Peyer’s patches which are an important part of the local immune system of the gastrointestinal system. The lymphocytes present in the Peyer’s patches are a part of the lymphatic system.
Different parts and cells of small bowel are specialized for secreting various useful hormones which facilitate the process of digestion in different ways. Below is the brief description of some of the important hormones secreted by small intestine.
The epithelial cells in the bowel secrete the secretin hormone. It stimulates the pancreas and liver to release bicarbonate-rich fluids into the lumen through pancreatic and bile ducts, respectively. These bicarbonate-rich fluids are used for the neutralization of acidic chyme from stomach and emulsification of fats.
The enteroendocrine cells in the duodenum are specialized for synthesizing and secreting cholecystokinin hormone. In the presence of this hormone, the pancreas releases digestive enzymes and gallbladder empties bile into the intestinal lumen. Another function of this hormone is to suppress hunger.
Gastric Inhibitory Polypeptide
The K cells in the mucosa of duodenum and jejunum synthesize gastric inhibitory polypeptide (GIP) as an endocrine hormone. It is transported by blood and blocks the secretion of hydrochloric acid (HCL) into the stomach. 
The GIP hormone also stimulates the beta cells in the pancreas to increase the secretion of insulin. Insulin, on the other hand, regulates the level of glucose in the blood. 
Crypts in the duodenum and jejunum contain numerous endocrine M cells which secrete motilin hormone. For improving peristalsis and preparing the gut for next meal, motilin is known as “housekeeper of the gut”. 
It stimulates the production of pepsin enzyme which digests proteins in the stomach. Meanwhile, motilin also plays a role in increasing the production of pancreatic polypeptide and somatostatin.
Interesting Small Intestine Facts
The longest and narrowest part of your digestive system, the small intestine plays a very important role both in the physical and chemical digestion of the food. Here are some interesting small intestine facts. Just go through the following list.
- Small intestine is responsible for absorption of over 95 percent of essential nutrients from the food.
- The small intestine is small in terms of its diameter and not the length. In terms of length, it is the longest part of gastrointestinal tract.
- It measures less than half the diameter of large intestine.
- The small intestine length increases after death. It may also measure longer than average when empty.
- Though the average small intestine length is 15 to 20 feet, in exceptional cases, it may reach over 34 feet!
- The length also varies across individuals with different heights.
- One square inch of mucosa may contain as many as 20,000 finger-like projections, called villi.
- The circular folds, villi and microvilli increase the absorptive surface of small intestine 600 times beyond that of a cylindrical tube.
- The cell membranes of cells on the surface of mucosa also have finger-like projections, called microvilli. Do you know around 130 billion microvilli are present in just one square inch of the small intestine mucosa?
- The folds, villi and microvilli can incredibly increase the surface area of the small intestine for the absorption of food. The total surface area of ten feet long section may measure over 30 square meter.
- Your small intestine can process over two gallons of food and liquids on daily basis.
- The segmentation contractions of small intestine mix the chyme up to 12 times per minute within a small segment of the bowel.
- This part of the digestive system holds the food for four hours for emulsification, mixing, chemical digestion and absorption.
- Three organs of the body, pancreas, liver and gallbladder, empty secretions into the lumen of small bowel to facilitate chemical digestion.
- Duodenum is the smallest and ileum is the longest part of the small bowel.
- There is division of labor among different parts. For example, duodenum carries out chemical digestion and prepares the chyme for absorption. On the other hand, most of the nutrients from food are absorbed in jejunum. The last part, ileum, is responsible for the absorption of the leftover nutrients.
- Is there a housekeeper in your intestine? Yes, the motilin hormone is known as “housekeep of the gut”. This hormone improves the peristaltic contractions and prepares the gut for accommodating and processing next meal.
- Do you know about nine liters of fluid enters the jejunum each day? The small bowel absorbs as much as seven liters and only around two liters is left to enter the large intestine.
Small Intestine Diseases
Small intestine is the principle digestive organ. It not only serves as a site for most of the digestion and absorption of food but also has a role in immunity and performs several other functions. So, a small intestine disease can adversely affect one or more of the functions of the organ.
Some of the small intestine disorders include cancer, ulcer, celiac disease, intestinal obstruction, intestinal lymphoma, tropical sprue, lactose intolerance, and so on. Discussed below are causes, symptoms and treatment of common intestinal disorders.
Small Bowel Obstruction
Small bowl obstruction refers to the partial or complete blockage of small bowel. Such a condition impedes the normal passage of luminal contents through the small intestines. This potentially dangerous condition can seriously affect the quality of your life.
Small bowel obstruction may occur due to multiple reasons, for example, cancer, internal scar tissue and strangulated hernia. A strangulated hernia is a protruding portion of the small intestine that comes out through a weak spot in the abdominal wall.
- Bouts of painful muscle contractions after intervals.
- Painful abdominal swelling which increases with time.
- Progressive constipation and inability to pass feces or even gas.
- Diarrhea due to partial obstruction.
- Nausea leading to vomiting.
- Low-grade fever and weakness.
Small bowel obstruction should not be taken lightly. It is a medical emergency and requires immediate professional treatment. In the first step, doctors may remove fluid and gas through a tube passed through the mouth or nose to decompress the distended abdomen.
In most cases, surgery is essential to clear mechanical obstruction from the small bowel. Sometimes, it becomes unavoidable to remove affected portion of the intestine through surgery. The severed ends are afterwards rejoined.
The celiac disease, also called celiac sprue, is a digestive disorder that is more common in people of European descent than in others. It may cause diarrhea, weight loss, fatigue and pain in bones.
Celiac disease is a condition that results from gliadin protein found in gluten. Gluten is a component of wheat that renders smoothness and elasticity to the flour. The presence of gluten in food produces an immune reaction. Such an immune reaction causes a damage to the lining of the small intestine.
- Gas and diarrhea.
- Fatigue and weight loss.
- Stools with foul-smell.
- Appearance of red spots or rash on skin.
- Abdominal bloating and pain in bones.
- Stunted growth in children under the age of 5.
- Tingling sensation in the arms and legs.
You can reduce the chances of the disease by taking a gluten-free diet. In case of falling victim to this disorder, doctors instruct to eliminate all sources of gluten from the diet. For the patients of celiac disease, the safe foods include plain meats, vegetables, fruits, potato, corn flours, soybean, rice, most dairy products and a moderate amount of oats.
Small Intestine Cancer
Knowing what to expect from cancer can help you cope with this disorder. What is cancer in general? When cells in your body begin to grow out of control, the condition is called cancer. Cells in any part of your body can become cancerous. When uncontrolled growth of cells occurs in the small intestine, you call it small intestine cancer.
Three types of small intestine cancers are most common and account for nearly 70% cases. These are: carcinoid tumors, sarcomas and lymphomas. Meanwhile, adenocarcinoma is the fourth major type of small intestine cancer. 
Causative factors for different intestinal cancers may be common, but each type has some of its own specific causes as well. For example, smoking, use of alcohol, celiac disease and Crohn’s disease are some of the causes of small intestine adenocarcinoma. Meanwhile, age, sex and diet can also play a role in this regard.
- Discharge of blood in feces.
- Dark or black-colored stools.
- Development of a lump in the abdominal area.
- Painful cramps in the abdomen.
- Unexpected and unexplained weight loss.
- Fatigue and weakness.
- Severe nausea leading to vomiting.
Effective treatment can be suggested and carried out only after proper diagnosis. So, if you experience any or all of these symptoms, explain everything to your doctor. The use of a therapy may also depend on the small intestine cancer stage. Surgery, radiation therapy and chemotherapy are some of the treatment options.
Duodenal ulcer is a type of peptic ulcer which affects the upper small intestine or duodenum. Another major type of peptic ulcer is gastric ulcer which damages the stomach wall.
Duodenal ulcer forms when the protective layer of duodenum is broken down. So, the intestinal wall is exposed to damage from hydrochloric acid and pepsin enzyme, coming from the stomach. With timely and effective treatment, the duodenal ulcer symptoms go away quickly.
Duodenal ulcer may form due to multiple causes. In most cases, it is due to two reasons. Firstly, a bacterial species, called Helicobacter pylori (H. pylori) damages the mucus lining of small intestine. Secondly, naproxen, aspirin and ibuprofen and other nonsteroidal anti-inflammatory drugs have the potential to breakdown intestine’s protective mucus layer. 
Different people experience different peptic ulcer symptoms. Sometimes, the symptoms of the disease do not appear at all. If they appear, you may experience a few or all of the following symptoms:
- A burning pain between the navel and the breastbone.
- Pain disappears after taking an antacid.
- Loss of appetite.
- Nausea and vomiting.
- Weight loss.
- Vomiting blood and black stools.
After the diagnosis of the condition through physical exam and endoscopy, your doctor will try to treat it using antibiotics that can kill H. pylori. They will also ask you to quit smoking and limit the use of alcohol.
The use of ibuprofen, aspirin and naproxen and other such drugs can increase the chance of your peptic ulcer coming back.
The cancer that occurs in your body’s lymph nodes is called lymphoma. What are lymph nodes? These are small organs that help the immune system and are present throughout the body including abdominal cavity.
While there can be Hodgkin or non-Hodgkin lymphomas, the intestinal lymphoma is essentially a non-Hodgkin lymphoma. It originates in the B or T cells. The most frequent sites for the occurrence of the disease include small intestine, stomach and ileocecal region.
A complication of celiac sprue may lead to intestinal lymphoma of the small bowel. Celiac sprue, on the other hand, is the body’s intolerance to gluten which is a component of wheat and several other grains. The presence of gluten triggers an immune reaction which damages the lining of small intestine.
The intestinal lymphoma of small intestine may arise due to different reasons. For example, it may result from the complication of celiac disease. Sometimes, developing in some other part of the body, lymphoma may spread to small bowel. In this case, it is called secondary lymphoma.
Smoking and consumption of alcohol, and the disease like previous colon cancer and Crohn’s disease are the potential risk factors for the intestinal lymphoma.
- Severe abdominal pain and cramps.
- Malabsorption of ingested food.
- Severe constipation and bowel obstruction.
- Rectal bleeding.
- Unexplained weight loss.
- Anxiety and depression.
- Fatigue and insomnia.
Several factors impact the choice of treatment for intestinal lymphoma including age, gender, medical history and stage of the disease. The treatment options, like surgery, chemotherapy and biological therapy may be used alone or in combination.
Biological therapy involves the slow intravenous injection of Rituximab which is a monoclonal antibody.
- Digestive Disease Center (MUSC), Small Intestine Function , Small Intestine 
- Cleveland Clinic, Digestive System 
- Wikipedia The Free Encyclopedia, Small Intestine , , Small Intestine Parts , Duodenum , Gastric Inhibitory Polypeptide , Motilin Function 
- InnerBody, Small Intestine 
- Encyclopedia Britannica, Gastric Inhibitory Polypeptide 
- American Cancer Society, Small Intestine Cancer 
- WebMD, Peptic Ulcer Disease 
- Siddiqi, L. H. (2011) Medical Histology, 5th Edition, Paramount Publishing Enterprise.
- The Johns Hopkins Complete Guide to Symptoms and Remedies (2004), published by Black Dog & Leventhal Publishers, Inc.