Chapter 3 How Nutrients Become You Objectives 1.Identify the six basic nutrient groups. 2.Distinguish the functions of the major parts of the digestive system. 3.Describe the processes of absorption and metabolism. 4.Explain factors affecting digestions and absorption. 5.Name common digestive disorders.

Introduction What does a car need to run? food is your body’s fuel when you eat, your body breaks down food and the nutrients it contains into simpler elements energy is released and nutrients are used to help build, repair and maintain body cell—then you body discards the by-products of this process as waste This chapter will help you picture the process of how your body uses food from beginning to end.

Six Groups of Nutrients Your Body Needs vitamins minerals water carbohydrates fats proteins Each nutrient has a specific job. Each nutrient, in recommended quantities, is vital to good health. What happens when the body does not get adequate amounts?

The Functions of Nutrients build and repair body tissues regulate all body processes provide energy

The Functions of Nutrients: Build and Repair Body Tissue all cells are formed with materials that come from foodall cells are formed with materials that come from food new cells account for your growthnew cells account for your growth nutrient needs during rapid growth are greater than any other time (prenatal period, infancy, adolescence)nutrient needs during rapid growth are greater than any other time (prenatal period, infancy, adolescence) What is a result of lack of nutrients during these periods?

The Functions of Nutrients: Regulate Body Processes maintaining the correct acid- base is a function of nutrients digestion, absorption and metabolism are also processes that rely on proper amounts of nutrients

The Functions of Nutrients: Provide Energy food is to your body what gas is to a carfood is to your body what gas is to a car food is a source of energy for performancefood is a source of energy for performance the quality of food affects your performancethe quality of food affects your performance energy is necessary for all life processes to occur (breathe, move, pump blood, provide heat)energy is necessary for all life processes to occur (breathe, move, pump blood, provide heat) carbohydrates and fats are the two main nutrients used for energycarbohydrates and fats are the two main nutrients used for energy

The Energy Value of Food calories: amount of heat needed to raise 1kg of water 1ºC 1gm Carbohydrates = 4 calories of energy 1gm Fat = 9 calories of energy 1gm Protein = 4 calories of energy 1gm Alcohol = 7 calories of energy

Objective 1. Identify the six basic nutrient groups. 2. Distinguish the functions of the major parts of the digestive system.

Review How many calories are in the following: 1gm Carbohydrates 1gm Protein 1gm Fat 1gm Alcohol What are the six main nutrient groups your body needs? What are the functions of nutrients? What are the two main nutrients the body uses for energy? At what time are nutrient needs the greatest?

Activity Individually Complete Worksheet: Determining Energy Values (whole class period)

The Process of Digestion Have you ever wondered what happens to a piece of food after you put it in your mouth? digestion: process by which your body breaks down food, and the nutrients in food, into simpler substances *the blood then carries these simple substances to cells for use in growth, repair and maintenance

Two Types of Digestion 1. mechanical (as food is chewed) 2. chemical (food mixed with acids and enzymes) enzymes: type of protein produced by cells that cause specific chemical reactions

The GI Tract As food is digested, it passes through a muscular tube leading from the mouth to the anus. This is called the GI tract. Burgundy = mouth and esophagus (10”) Brown = stomach (8”) Green = small intestine (20’) Orange = large intestine (3’6”) The average length of the human digestive tract is feet.

The Process of Digestion: Step 1 In the Mouth Begins with mastication (chewing) the teeth and tongue move food and crush prepares food for swallowing about 9000 taste buds in the mouth the taste and smell of food trigger salivary glands in your mouth

The Process of Digestion: Step 1 In the Mouth these glands produce saliva (99% water and 1% chemicals) one in particular is salivary amylase (breaks down carbohydrates, starches, to simple sugars) saliva moistens mouth, softens and dissolves foods, helps cleanse the teeth and neutralize mouth acids

The Process of Digestion: Step 1 In the Mouth Experiment Chew 2 unsalted crackers for 2 minutes without swallowing Compare how the crackers tasted at first with how they tasted after 2 minutes. The change in taste from starchy to sweet was caused by the chemical action of the enzyme salivary amylase—breaks down the start in food to simple sugars

The Process of Digestion: Step 2 In the Esophagus the esophagus is a tube about 10” long that connects the mouth to the stomach there are 2 tubes in the throat, the other being the trachea when you swallow food, a flap of skin called the epiglottis closes to keep food from entering the trachea breathing automatically stops when you swallow food to prevent choking a series of squeezing actions by the muscles in the esophagus, called peristalsis, helps food move through the tube

The Process of Digestion: Step 3 In the Stomach when you eat, the stomach produces gastric juices to prepare for digesting the oncoming food gastric juices contain hydrochloric acid, digestive enzymes and mucus the mixture of gastric juices and chewed and swallowed food combine in the stomach—this mixture is called chyme

The Process of Digestion: Step 3 In the Stomach the acid in the stomach is as strong as car battery acid, but a thick lining called mucosa protects the stomach from its juices protein absorption begins in the stomach—the gastric enzyme that breaks down protein is pepsin food stays in the stomach only 2-3 hours from the stomach, chyme moves to the small intestine

The Process of Digestion: Step 4 In the Small Intestine 95% of digestion occurs here has 3 sections—duodenum, jejunum and ileum takes about 5-14 hours for food to travel from the mouth through the small intestine peristalsis helps the food move through the small intestine Small intestine helpers: pancreas liver

The Process of Digestion: Step 4 In the Small Intestine Pancreas behind the stomach neutralizes hydrochloric acid that has come from the stomach produces enzymes that aid digestion in the small intestine (breaks down fats, carbohydrates and proteins) Basic PartEnzyme That Does the Work proteinsamino acidsproteases carbohydratesmonosaccharidessaccharidases fatsfatty acids, glycerol, monoglycerides lipases

The Process of Digestion: Step 4 In the Small Intestine Liver located above the stomach produces bile, which aids fat digestion bile helps disperse fat in the water-based digestive fluids bile is store in the gall bladder

The Process of Digestion: Step 5 In the Large Intestine aka the colon very little digestion occurs here main job is to reabsorb water chyme stays in the colon 1-3 days before elimination solid wastes that result from digestion are called feces the end of the large intestine is called the rectum—the feces collect here until they are ready to pass from the body through the anus

Objectives 1.Describe the processes of absorption and metabolism. 2.Explain factors affecting digestion and absorption.

Review Complete Worksheet: Food Breakdown (5-10 minutes) and Complete Worksheet: Nutrient Digestion in the Small Intestine (5-10 minutes)

Activity Complete in the Lab The Digestion Experiment I will assign your lab partners!

Objectives 1.Describe the processes of absorption and metabolism. 2.Explain factors affecting digestion and absorption.

Absorption of Nutrients After being digested in the small intestine, nutrient in food are ready for absorption. absorption: passage of nutrients from the digestive tract into the circulatory or lymphatic system

Absorption of Nutrients The wall of the small intestine is pleated with 1000’s of folds that are covered with villi. The inside surface area of the small intestine is about 600 times larger than that of a small tube. how? villi: tiny, fingerlike projections that give the lining of the small intestine a velvetlike texture every cell of the villus is covered with microvilli, which are microscopic hairs that help catch nutrient particles

Absorption of Nutrients: Water-Soluble Nutrients dissolve in water include amino acids, monosaccharides, minerals, most vitamins and water tiny blood vessels in the villi, called capillaries, absorb water-soluble nutrient into the bloodstream carried to the liver

Absorption of Nutrients: Fat-Soluble Nutrients dissolve in fat include a few vitamins, fatty acids, glycerol and monoglycerides lymph vessels in the villi, called lacteals, absorb fat-soluble nutrients into the lymphatic system carried to the bloodstream The large intestine finished the job of absorption.

Metabolism once the nutrients are digested and absorbed, the circulatory system takes over the circulatory system carries nutrient and oxygen to cells metabolism: all the chemical changes that occur as cells produce energy and materials needed to sustain life

Metabolism Through metabolism, cells breakdown some nutrients to release energy, called ATP ATP: storage form of energy in the body **when the body needs energy, chemical reactions break down ATP to release energy**

Factors that Affect Digestion and Absorption Have you ever been nervous or worried and felt food in your stomach like a rock? eating habits emotions food allergies physical activity Healthy lifestyle choices can help you avoid many GI problems.

Factors that Affect Digestion and Absorption: Eating Habits too little food can cause a lack of nutrients, which can affect how your body will digest and absorb other nutrients eat plenty of fruits and vegetables and whole grain products—they are high in fiber eating too much food too fast places stress on mechanical and chemical reactions needed for digestion

Factors Affecting Digestion and Absorption: Emotions emotions like fear, anger and tension can cause digestive disorders make a point to reduce stress and tension while eating HOW?

Factors Affecting Digestion and Absorption: Food Allergies the immune system is the body’s defense system made up of the tonsils, thyroid, lymph glands, spleen and white blood cells protects the body against disease and foreign materials with proteins called antibodies food allergy: a reaction of the immune system to some substance found in food vomiting stomach pain intestinal distress skin rashes swelling breathing problems

Factors Affecting Digestion and Absorption: Physical Exercise exercise can aid digestion and metabolism stimulates a healthy appetite and strengthens the muscles of internal organs it helps move food through the GI tract helps reduce stress

Digestive Disorders Use worksheet for note taking.

Digestive Disorders: Diarrhea diarrhea: frequent expulsion of watery feces diarrhea causes food to move through the digestive system too quick for nutrients to be fully absorbed Cause food sensitivity, harmful bacteria or stress Cure water to restore fluid loss, medications

Digestive Disorders: Constipation Cause erratic eating habits, low fiber intake, lack of physical activity, not drinking enough water Cure laxatives, high fiber diet, exercise, drink plenty of water constipation: occurs when chyme moves very slowly through the large intestine (too much water is reabsorbed from chyme) causes the feces to become hard, making BM’s painful—hemorrhoids

Digestive Disorders: Indigestion Cause stress, eating too much or too fast, eating certain foods Cure antacids (neutralize stomach acids), modify diet, eat in a relaxed atmosphere indigestion: difficulty in digesting food *symptoms include gas, stomach cramps and nausea

Digestive Disorders: Heartburn Cause stomach acid flowing back into the esophagus (aka reflux) Cure antacids heartburn: burning pain in the middle of the chest **has nothing to do with the heart

Digestive Disorders: Ulcer Cause bacterium, heredity, stress, excessive alcohol use **ulcerated area becomes inflamed and person experiences a burning pain Cure antibiotic therapy, eat nutritious diet, decrease stress, physical exercise ulcer: open sore in the lining of the stomach or small intestine

Digestive Disorders: Gallstones Cause when bile forms solid particles (stones) in the gallbladder Cure diets low in fat, removal of gall bladder gallstones: small crystals that form from bile in the gallbladder

Digestive Disorders: Diverticulosis Cause occurs when intestinal muscles become weak (when the diet is too low in fiber), high-fat diet and an inactive lifestyle Cure high-fiber diet which will help keep the intestinal muscles toned diverticulosis: a disorder in which many abnormal pouches form in the intestinal wall