Which of the following food constituents is not digested but is still important for us?

Background for Teachers Dietary fiber is not a nutrient, but it is necessary to regulate digestion and appears to prevent some epidemiological diseases. DEFINITIONS: WATER: a compound composed of two atoms of hydrogen and one atom of oxygen. Water is the most important of all the essential nutrients, since human life cannot be sustained without water. FIBER: A loose term denoting the substances in plant food that are not digested by human digestive enzymes. It provides almost no calories. CRUDE FIBER: The residue of plant food remaining after extraction with acid and alkali. DIETARY FIBER: The residue of plant food resistant to hydrolysis by human digestive enzymes. (l gm crude fiber = 2-4 gm dietary fiber.) In addition to simple and complex carbohydrates, many plants that we eat for food contain cellulose, which is not broken down, digested and used by our body. It is tough and stringy and is essential for regulating the body. It is called dietary fiber. The cellulose strings in a stalk of celery is a good visible example. Dietary fiber is a non-nutrient because it is not digested or absorbed by the body. It helps to move food through the body and aids digestion by (1) attracting water to the small and large intestines, and (2) the water increases bulk in foods and keeps the mass of fiber, food particles, digestive juices soft and moving though the system. Fiber is thought to be a protective agent for certain diseases, including colon cancer, diverticulosis*, and coronary...

Eat more fiber. You've probably heard it before. But do you know why fiber is so good for your health? Dietary fiber — found mainly in fruits, vegetables, whole grains and legumes — is probably best known for its ability to prevent or relieve constipation. But foods containing fiber can provide other health benefits as well, such as helping to maintain a healthy weight and lowering your risk of diabetes, heart disease and some types of cancer. Dietary fiber, also known as roughage or bulk, includes the parts of plant foods your body can't digest or absorb. Unlike other food components, such as fats, proteins or carbohydrates — which your body breaks down and absorbs — fiber isn't digested by your body. Instead, it passes relatively intact through your stomach, small intestine and colon and out of your body. Fiber is commonly classified as soluble, which dissolves in water, or insoluble, which doesn't dissolve. • Soluble fiber. This type of fiber dissolves in water to form a gel-like material. It can help lower blood cholesterol and glucose levels. Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium. • Insoluble fiber. This type of fiber promotes the movement of material through your digestive system and increases stool bulk, so it can be of benefit to those who struggle with constipation or irregular stools. Whole-wheat flour, wheat bran, nuts, beans and vegetables, such as cauliflower, green beans and potatoes, are good sources...

Stomach and pyloric valve Your stomach is a muscular sac about the size of a small melon that expands when you eat or drink. It holds as much as a gallon (3.8 liters) of food or liquid. Once your stomach breaks down the food, strong muscular contractions known as peristaltic waves push the food toward the pyloric valve. This valve leads to the upper portion of your small intestine, a segment known as the duodenum. Gastroparesis is a condition that affects the normal spontaneous movement of the muscles (motility) in your stomach. Ordinarily, strong muscular contractions propel food through your digestive tract. But if you have gastroparesis, your stomach's motility is slowed down or doesn't work at all, preventing your stomach from emptying properly. The cause of gastroparesis is usually unknown. Sometimes it's a complication of diabetes, and some people develop gastroparesis after surgery. Certain medications, such as opioid pain relievers, some antidepressants, and high blood pressure and allergy medications, can lead to slow gastric emptying and cause similar symptoms. For people who already have gastroparesis, these medications may make their condition worse. Gastroparesis can interfere with normal digestion, cause nausea, vomiting and abdominal pain. It can also cause problems with blood sugar levels and nutrition. Although there's no cure for gastroparesis, changes to your diet, along with medication, can offer some relief. Symptoms Signs and symptoms of gastroparesis...

The human digestive system refers to the organs that take in food and break them down. Digestion describes the complex process that enables the nutrients in food to enter the body and its cells. Food contains all of the nutrients a person’s body needs for health, but large, complex compounds bind them. During digestion, the body breaks these compounds down into smaller parts. This enables them to enter cells, providing energy and other benefits. This article explains how the body digests food from when it enters the mouth to when it exits the body. It also suggests some tips for healthy digestion and how to identify problems. Share on Pinterest The human gastrointestinal tract, also called the alimentary canal, is around It • the mouth, or oral cavity • the esophagus • the stomach • the small intestine • the large intestine, or colon • the rectum In addition, the following organs support digestion, for example, by chewing or adding enzymes and other secretions that enable the body to absorb nutrients: • the • the tongue • the salivary glands • the • the • the Together, these organs provide mechanical processing, the secretion of enzymes and bile to help break down compounds, and the excretion of waste. Some terms to describe • ingestion, which includes chewing and swallowing • the secretion of substances that enable food and nutrients to move through the body effectively • propulsion, where muscles move the contents of the canal forward • digestion, the breakdown of food, ...

Term Meaning Digestive system The body system that converts food into energy and nutrients to fuel the body Chemical digestion The breaking down of food using chemical agents, such as enzymes and bile Mechanical digestion The breaking down of food by physical means, such as chewing Absorption The process by which nutrients pass through the walls of the digestive system into the blood Excretory system The body system that removes metabolic wastes from the body Excretion The process of removing wastes and excess water from the body The chyme is slowly transported into the small intestine, where most chemical digestion takes place. Bile, which is made in the liver, is released from the gallbladder to help digest fats. In addition, enzymes from the pancreas and intestinal walls combine with the chyme to start the final part of digestion. The chyme then enters the large intestine. Here, water is removed and bacteria break down some undigestible materials, producing important compounds (such as vitamin K). The concentrated waste material that remains is called feces, which is passed into the rectum and eliminated from the body through the anus. The small intestine is actually longer than the large intestine. In fact, at approximately 20 feet in length, the small intestine is nearly four times as long as the large intestine (5 feet long)! However, the intestines are named for their diameters, not their lengths. The large intestine has a diameter of about 3 inches compared to the ...

Foods that are high in fiber or have hard shells, like sweetcorn, often pass through the body undigested. This is because they are hard to break down. However, other undigested foods in stool could indicate an underlying condition, such as Crohn’s disease. When undigested food in the stool occurs with a In this article, we look at reasons why undigested food may appear in stool and when a person should speak with a doctor. Share on Pinterest Antenore/Getty Images There are some reasons why the body might not completely digest foods that do not cause concern. Undigested food can appear in the stool if there is material in food that is indigestible, such as cellulose in some high- It could also happen if food passes too quickly through the High-fiber foods Fiber refers to the indigestible part of plant foods. A high-fiber diet can have many benefits, including keeping the digestive system healthy and keeping bowel movements regular. When a person eats high-fiber foods, it is common for some undigested material to appear in the stool because the body cannot fully break down the tough material. Fiber also speeds up a person’s bowel movements by adding bulk to the stool, which encourages the intestinal walls to move. This movement pushes food through the digestive tract. If food moves too quickly through the digestive system, a person may not fully digest some foods. Certain foods are more likely than others to be difficult to fully digest. These foods include: • • seeds • • • ...

Biologist William K. Purves of Parietal cells in the mucosa, the inner cell layer of our digestive tract, secrete hydrochloric acid (HCl) into the stomach's lumen, or cavity. The solution in the lumen may have a pH of one or less10 times as acidic as pure lemon juice. This fact raises two distinct questions: how can the mucosa form HCl without being attacked in the process? And why doesn't the acid, once present in the lumen, attack the mucosa? First, the mucosa doesn't get digested as it secretes the HCl because the pH within the parietal cells remains near neutrality by the following mechanism (note that all parts of the mechanism take place simultaneously): (1) Potassium ions, K +, diffuse passively from the parietal cell into the lumen. (2) An active transport pump brings K + back into the parietal cell, simultaneously secreting H + from the cell to the lumen. As much K + returns by this route as leaks in (1). (3) Chloride ions, Cl -, diffuse passively from the cell to the lumen, and their negative charges balance the positive charges of the secreted H +. (4) An exchanger on the opposite face of the parietal cell balances this loss of Cl - by importing Cl - from the blood in exchange for bicarbonate ions (HCO3 -). (5) Within the cell, water reacts with carbon dioxide (CO 2) to form carbonic acid (H 2CO 3), which dissociates into H + and HCO 3 -. The figure ( right) summarizes these steps. In summary, the secreted HCl arises from H + (from water) and Cl - from the blood...