Presentation on theme: "H OW N UTRIENTS B ECOME Y OU Chapter 3 Food Science."— Presentation transcript:
H OW N UTRIENTS B ECOME Y OU Chapter 3 Food Science
F OOD, N UTRIENTS, AND E NERGY Food plays more roles than satisfying hunger The food you eat becomes a part of you Nutrients from food are your body’s source of fuel and building materials
S IX N UTRIENT G ROUPS There are six groups of nutrients your body needs Each nutrient has a specific job to perform for the body Carbohydrates (compound) Fats (compound) Proteins (compound) Vitamins (compound) Minerals (elements) Water (compound)
C HEMISTRY OF N UTRITION Learning about health and nutrition requires SOME knowledge of chemistry Elements : simplest substance from which all matter is formed Matter : is anything that takes up space and has a measurable quantity. Atom : smallest part of an element that can enter into a chemical reaction Molecule : smallest amount of a substance that has all the characteristics of the substance Molecules are made up of two or more atoms that are bonded together Having some knowledge of chemistry will help you grasp how nutrients interact in your body
F UNCTIONS OF N UTRIENTS Build and Repair body tissues Regulate all body processes Provide energy When your body is performing all of these functions in harmony, your potential for optimum wellness increases
Find and highlight on the periodic table the elements essential to human health. (There are 20).
E NZYMES In chemical digestion, food is mixed with powerful acids and enzymes. Enzymes : a type of protein produced by cells that cause specific chemical reactions. http://www.youtube.com/watch?v=SyVcyT- fOaohttp://www.youtube.com/watch?v=uSkLR50 Ce7g
T HE D IGESTIVE S YSTEM Digestion is the process by which your body breaks down food and the nutrients in food, into simpler substances. http://www.youtube.com/watch?v=SyVcyT-fOao
T HE P ROCESS OF D IGESTION Digestion : process by which your body beaks down food, the nutrients in the food, into simpler substances. The blood then carries these substances to the cells to use in growth, repair, and maintenance. Digestion occurs through mechanical and chemical means Mechanical digestion : happens as food is crushed and churned Chemical digestion : food is mixed with powerful acids and enzymes. Enzymes : type of protein produced by cells that case specific chemical reactions. i.e. cause food particles to break apart into simpler substances. Gastrointestinal (GI) Tract : As food is digested, is passes through a muscular tube leading from the mouth to the anus. 25-30 feet in length.
I N THE M OUTH Mastication: chewing, first step in the digestive process, prepares food for swallowing Chewing food well aids digestion because the body can break down small food particles faster than large food particles About 9,000 taste buds that cover the surface of the tongue. This taste sensation along with good food odors and the thought of food triggers salivary glands in the mouth. (Produces saliva) Saliva is mixture of about 99% water with a few chemicals (salivary amylase-found only in the mouth) helps to digest starches in foods. Without saliva, your mouth is dry and food seems to have little taste. Saliva moistens, softens, and dissolves food. Also helps to clean teeth and neutralize mouth acids.
I N THE E SOPHAGUS As you chew, the muscles in your mouth and tongue form the food into a small ball. Your tongue moves this ball of food to the back of your mouth and you swallow. Tube that helps food pass from the mouth to the stomach Only one of two tubes in the throat. (Trachea/windpipe) is the other. Epiglottis is a flap of skin that keeps the trachea closed when you swallow and keeps food from entering the windpipe Breathing automatically stops when you swallow food to help prevent choking Peristalsis: a series of squeezing actions by the muscles in the esophagus move food through the tube. Peristaltic action occurs throughout the esophagus and intestine to help mechanically move and churn food.
S TOMACH (G ASTRIC ) When you eat, the stomach produces gastric juices in order to prepare for the food Gastric juices : contains hydrochloric acid, digestive enzymes, and mucus. Mucus : thick fluid that helps soften and lubricate food (helps prevent the stomach from its strong acidic juices Chyme : mixture of gastric juices and chewed food Acid in the stomach is almost as strong as battery acid found in a car Protein digestion begins in the stomach Pepsin : major gastric enzyme that begins to chemically break down protein Most people can hold about one quart of food in their stomach Food generally remains there for 2-3 hours, depending on the type of food. Liquids leave before solids Carbohydrates and proteins digest faster than fats From the stomach, it moves to the small intestine
S MALL I NTESTINE 95% of digestion occurs in the small intestine Coiled in the abdomen in circular folds. 3 sections (duodenum-12 inches, the jejunum-4 feet, and the ileum-5feet). When stretched, it is about 20 feet in length and 1 inch in diameter. 5-14 hours for food to travel from the mouth through the small intestine Needs less acidic environment than the stomach to perform its work. Pancreas: long elongated gland behind the stomach, helps create the correct environment (secretes bonate, which neutralizes the hydrochloric acid) Pancreas: Produces digestive enzyme that helps digestion take place in the small intestine.
S MALL I NTESTINE (C ONTINUED ) Liver: involved in the chemical digestion Large gland above the stomach Produces Bile (helps disperse the fat in the water- based digestive fluids so they can be broken down.
L ARGE I NTESTINE Large Intestine is sometimes called the colon About 3-3 ½ Feet long (5 to 6 feet stretched) Main job of large intestine is to reabsorb water When liquid enters the large intestine, it is referred to as chyme Chyme usually stays in the colon 1-3 days before being expelled Feces : solid wastes that result from digestion The end of the large intestine is called the rectum Feces is expelled through the anus
A BSORPTION OF N UTRIENTS Absorption : passage of the nutrients from the digestive tract into the circulatory or lymphatic system Villi : tiny, fingerlike projections that give the lining of the small intestine a velvet-like texture Microvilli : microscopic hears that help catch nutrient particles on villi Water soluble nutrients : can be dissolved in water Fat-soluble nutrients : can be dissolved in fat
M ETABOLISM Metabolism: all chemical changes have occurred and cells produce energy and material needed to sustain life Cells make compounds that are used for energy. Some are stored for later. ATP (adenosine triphosphate): source of immediate energy fond in muscle tissue. Chemical break down ATP to release energy
F ACTORS A FFECTING DIGESTION & A BSORPTION Eating Habits Emotions Food Allergies Reaction to the immune system to certain proteins found in food. Protein that stimulates the immune system to produce antibodies is called an allergen. Physical Activity
D IGESTIVE D ISORDERS Diarrhea : frequent expulsion of watery feces Constipation : occurs when chyme moves very slowly through the large intestine Indigestion : difficulty in digesting food Heartburn : burning pain in the middle of the chest (has nothing to do with the heart-caused by acid) Ulcer : open sore in the lining of the stomach or small intestine Gallstones : small crystals that form from bile in the gallbladder Diverticulitis : disorder in which many abnormal pouches form in the intestinal wall
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