Your Health Food Poisoning

Food poisoning occurs when bacteria in food are not killed before being ingested. For example, if food is left out in the summer heat, particularly anything containing dairy products, it provides an ideal growth medium for a microorganism called Staphylococcus. If food is kept refrigerated, this bacteria cannot grow and produce the chemical toxins that cause symptoms. Improper handling of food may also cause bacterial contamination. If chicken or fish, which usually harbors Salmonella...

Your Health The Importance Of Brushing Your Teeth

Tooth decay begins when dental plaque, a layer of bacteria, trapped sugars, and mouth debris, sticks to teeth. Plaque provides a safe haven for bacteria to live and metabolize the bits of trapped food. Bacterial waste consists of assorted acids that damage tooth enamel. Once the enamel is damaged, the bacteria break down the proteins of the tooth and cause tooth decay or cavities. Periodontal disease may result if the plaque builds up on the gums. This buildup, called tartar or calculus, may...

Your Health Ulcers

Imagine the body attacking and damaging its own tissues. When a person has a gastric or peptic ulcer, the hydrochloric acid in the stomach attacks the walls of the stomach, damages the mucosa, and may lead to severe bleeding that compromises the body's ability to deliver adequate oxygen to tissues. This bleeding results in severe anemia. Until the 1980s, ulcers were believed to be caused by stress, alcohol use, or taking excessive amounts of aspirin. Aspirin and other nonsteroidal...

Carbohydrates

Carbohydrates, a group of molecules that include sugars and starches, provide energy to the body when the molecules are broken down. All carbohydrates contain carbon, hydrogen, and oxygen. They are categorized by size monosaccharides, disaccharides, and polysaccharides. Monosaccharides, such as glucose, fructose, and galactose, are simple sugars. Usually, the ratio of each of carbon to hydrogen and oxygen is 1 2 1 such that there is one carbon to two hydrogens to one oxygen. Most of the sugars...

Informed Choices About Eating

The first and most important aspect in eating a healthy diet is learning about food. Reading the nutritional information on foods is an important way to learn how many calories the food contains and the distribution of fats, carbohydrates, and other substances. The federal government has set strict definitions for 12 terms that are used frequently on food labels, including free, reduced, lean, less, light, extra lean, low, fewer, high, more, good source, and healthy. The Food and Drug...

Did You Know

Fiber is important for digestion at any age, from teenagers to the elderly. There are soluble and insoluble types of fiber. Soluble types of fiber are found in beans, oat, barley, broccoli, prunes, apples, and citrus fruits. This fiber forms a gel that slows the movement of chyme through the intestine and binds cholesterol. Ordinarily, two-thirds of the cholesterol that enters the intestine is reabsorbed. Fiber keeps cholesterol in the digestive tube until elimination, which helps to decrease...

Saliva

As stated earlier, digestion is a process that breaks down food to sizes that can be absorbed by cells. There are two components to the process physical and chemical. The physical aspects of digestion in the mouth occur when we bite, tear, and chew food. This breaks the food into smaller, but still fairly large, chunks of food. Chemical digestion in the mouth involves saliva. Most of the saliva is secreted by three pairs of salivary glands the parotid, submandibular, and sublingual. These...

Connections

Nutrients must be broken down to a size capable of being absorbed into a microscopic cell. Each type of nutrient has a basic building block that can be absorbed. For sugars, this basic unit is a monosaccharide. For proteins, this is an amino acid. Lipids in the form of triglycerides are broken into glycerol and fatty acid chains, while cholesterol is absorbed intact. The wall of the digestive tract is made up of four major layers mucosa, submucosa, muscularis, and a connective tissue covering...

Lactose Intolerance

Because Amy has a form of lactose intolerance, she cannot digest milk unless it is in the form of yogurt, hard cheese, or cottage cheese. Drinking any milk products that contain lactose, such as the chocolate shake, will result in discomfort. Lactose, the carbohydrate component of milk, must be broken into its two monosaccharides, glucose and galactose, to be absorbed in the small intestine, most often in the jejunum. As babies, most people produce lactase, the enzyme that breaks up lactose,...

Digestion and Nutrition

On the way home from her morning classes, Amy stops for lunch at a fast-food resturaunt. Amy is in a hurry and she knows the meal will be served fast and she knows the food is safe. The food may not be the tastiest in the world, or very good for her, but it will get her through lunch. Amy has eaten in this kind of place hundreds of times before. She orders a burger, fries, and a chocolate shake. She knows the burger and fries have lots of fat and salt that she does not need. She also knows the...

Survey Of The Digestive Process And Components

The process of taking food into the mouth is called ingestion. The mouth receives the ingested food, breaks it up into smaller pieces, mixes it with saliva, and sends the food as a bolus to the pharynx, then into the esophagus. In addition to the physical digestion of breaking the food into smaller pieces, some chemical digestion begins in the mouth, especially for starches. Then the esophagus transports the bolus of food to the stomach. A detailed description of this part of the process can be...

Accessory Organs The Liver Gallbladder And Pancreas

The liver and the gallbladder are two important accessory digestive organs that work with the small intestine. The liver Figure 6.3 Villi and microvilli (illustrated here) act to increase the surface area of the small intestine, thus increasing the potential for nutrient absorption. Villi are finger-like projections on the surface of the intestine, and microvilli are smaller projections stemming from the villi. Figure 6.3 Villi and microvilli (illustrated here) act to increase the surface area...

Your Health Heartburn

Heartburn occurs when the stomach contents pass back up into the esophagus. This regurgitation can occur when the person vomits, the stomach is overfull, or the person is obese, pregnant, or running. The cardiac sphincter and the diaphragm do not entirely close off the connection to the stomach. It is fairly easy to overcome these barriers and bring stomach contents back up into the tube. Because the pH of the stomach fluids is usually below 4, or about the strength of a car's battery acid, the...

Your Health Empty Calories

Sometimes foods are described as having empty calories. This means that the item is made mostly of sugar, probably sucrose, and not much of anything else. When carbohydrates are ingested along with proteins, lipids, vitamins, and minerals, they form part of a balanced diet that fills our nutritional needs. of proteins starts out simple, and then becomes more complex, depending on the protein. The function of the protein depends on its structure. The chain of amino acids will bend and twist to a...

Fad Diets

Currently, there are many fad diets being advertised. Some recommend eating all protein, while others recommend special drinks or pills. No matter what the fad diet, unsound weight loss programs tend to have some similar characteristics. They promise dramatic weight loss over a short period of time they recommend eating an extremely low number of calories, usually without medical supervision and they frequently try to make adherents to the diet depend on certain foods, usually provided by them...

Food Pyramids Obesity And Diabetes

An estimated 60 of Americans are overweight and 25 are obese. Obesity can be measured in several ways. One method states that if a person weighs more than 20 of the ideal weight according to the height weight chart, the person is obese. This method does not take into account an athlete who may weigh more than a nonathlete because of muscle, not fat. Another method of measuring obesity is to measure percentage of body fat. If a person's body fat is more than 25 for a man or 30 for a woman, that...

Large Intestine Anatomy And Digestion

Rectum And Anal Canal Anatomy

The large intestine (Figure 7.1) is a tube about 5 feet long and Figure 7.1 The large intestine consists of the cecum, colon, rectum, and anal canal. It is last place where the body will remove nutrients before the waste is excreted. Figure 7.1 The large intestine consists of the cecum, colon, rectum, and anal canal. It is last place where the body will remove nutrients before the waste is excreted. 2.5 inches in diameter. It is wider than the previous sections of the digestive tube and can...

Structure Of The Digestive Tube

Four Walls The Digestive Tract

Throughout the digestive tube, the walls of the organs are made up of four layers mucosa, submucosa, muscularis, and the serosa or adventitia (Figure 4.2). The innermost layer of the digestive tube is the mucosa. This layer is composed of three parts the epithelium, the lamina propria, and the muscularis mucosae. The innermost part of the mucosa is the epithelium. Most of the epithelial layer is made up of a single layer of cells called columnar epithelial cells. These cells are lined up like...

Digestion In The Small Intestine

Fat Absorption

When acidic chyme enters the duodenum, it triggers several events. The acid, along with short proteins called peptides and fatty acids in the chyme, causes cells at the beginning of the duodenum to secrete intestinal fluid. About 1 to 2 quarts of this digestive fluid is produced each day. The intestinal juice, which contains some mucus, is alkaline and helps to neutralize the acidic nature of chyme and protect the duodenum from the effects of the acid. The chyme also causes the release of two...

Robert J Sullivan

President and Surgeon-in-Chief of the Texas Heart Institute Clinical Professor of Surgery at the University of Texas Medical School, Houston, Texas A Haights Cross Communications Company Philadelphia Copyright 2004 by Infobase Publishing All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the...

Digestion Absorption and Elimination

Digestive System

Let's get back to Amy and her lunch mentioned in Chapter 1. She will eat her hamburger, fries, and chocolate shake, but how do these nutrients get to the tissues in the body that need them Digestion is the process of preparing foods to enter the body. This may sound strange, but any foods inside the digestive system are not yet actually in the body. The digestive system is a long tube (about 30 feet when relaxed) with openings at both ends (Figure 4.1). This tube is contained within the body...