Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Food politics wikipedia , lookup
Oral rehydration therapy wikipedia , lookup
Epidemiology of metabolic syndrome wikipedia , lookup
Dietary fiber wikipedia , lookup
Low-carbohydrate diet wikipedia , lookup
Selfish brain theory wikipedia , lookup
Gastric bypass surgery wikipedia , lookup
Food choice wikipedia , lookup
Unit 2 Digestion, Basic Chemistry, and Carbohydrates Chapter 3 The Human Body: Are We Really What We Eat? Why Do We Want to Eat? Food is intimately connected to our sense of ________________, but also stimulates our senses of Sight Smell Touch Hearing This ultimately impacts: _________________ and _____________________ Hunger vs. Appetite Hunger: ____________________ drive for food Nonspecific Can be satisfied by a variety of different foods Appetite: ______________________ desire to consume specific foods Aroused by environmental cues Additional terms __________________: feeling of being full __________________: physiological need for food yet no appetite How are these factors controlled? ________________ System and ______________________ System Signals from the brain cause hunger and satiation (___________________ phase of nervous system) Nerve receptors in the stomach and small intestine send signals to the brain to indicate if they are full or empty Blood glucose levels trigger the release of hormones called insulin and glucagon The ____________________________ region of the brain receives these signals _________________________ triggers feelings of hunger or satiation (__________________) Integrates signals from nerve cells in other body regions and from chemical messengers Special cells lining the stomach and small intestine send signals to the brain to indicate if they are full or empty The hypothalamus can do these functions by releasing __________________. Hormones Hormones: chemical ___________________ secreted into the bloodstream by ________________________ to help regulate body functions Pancreatic hormones, insulin and glucagon, maintain blood glucose levels Feeling full (satiated) results from signals from the stomach and rise in blood glucose Nervous System “________________________” - Stomach distension by food stimulates the release of gastric juices and other hormones. Not all foods have the same effects on our feelings of hunger Proteins have the _________________ satiety value Carbohydrates have a ______________ satiety value than fats __________________ foods provide a sense of satiety _________________ foods are more filling than semi-solid foods or liquids What Happens to the Food We Eat? Food undergoes three processes: _____________________—large food molecules are broken down to smaller molecules, mechanically and chemically _____________________—process of taking these products through the intestinal wall _____________________—undigested portions of food and waste products are removed from the body Gastrointestinal (GI) tract: A series of organs arranged in a long tube that work together to ________________ foods The GI tract includes: Organs such as the stomach, intestines ______________________: muscles that control the passage of food material from one organ to the next The Flow of Digestion Digestion begins in the ________________ __________________ phase of digestion: Hunger and appetite work together to ________________ the GI tract for digestion First thought of food (_______________ system) stimulates the release of digestive juices ___________________ moistens the food and mechanically breaks it into smaller pieces ____________________ contains digestive juices secreted by the salivary gland in the mouth Bicarbonates neutralize ____________ Mucus ___________________ the food and oral cavity Antibodies and lysozymes fight oral bacteria ___________________ are complex chemicals that induce chemical changes in other substances to speed up bodily processes Salivary amylase begins _______________ digestion ________________ receptors detect distinct tastes: Bitter, sweet, salty, sour, and umami __________________ receptors detect aromas of foods The mass of food chewed and moistened in the mouth is called ____________________ The ____________________ covers the opening to the trachea during swallowing Food travels from the mouth to the stomach through the ____________________ How does food travel through the Esophagus to the Stomach? ____________________ is the muscular contractions moving food through the GI tract Digestion in the Stomach __________________ - a hormone secreted by stomach lining cells that stimulates gastric juice Gastric juice contains ___________________________ (HCl) denatures proteins and activates pepsin ___________________ – enzyme to digest protein _______________________________ – enzyme to digest fat _______________________________ – protein to absorb vitamin B12 Stomach does more than help with chemical digestion ___________________: semi-solid product of mechanical and chemical digestion in the stomach How is the stomach protected from the gastric juices or more specifically HCl? The pH Scale Acid? Base? pH ? Pure water is neutral/human blood is close to neutral Tissues lining the stomach are generally protected from the effects of acidity ____________________ layer protects the stomach lining from the acid in gastric juices Digestion in the Small Intestine From the stomach, chyme is slowly released through the _______________ sphincter to the small intestine Small intestine is composed of 3 sections ______________________ valve (sphincter) connects the small intestine to the large intestine Most of the digestion and absorption take place in the small intestine Digestion in the Large Intestine The large intestine is also referred to as the ____________ or ________________ _____________ assist with final digestion Its main function is to store undigested food material and absorb water, short chain fatty-acids, and electrolytes Are we forgetting something? ________________ and ___________________ How is Chemical Digestion Accomplished? Enzymes Speed Up Digestion _____________________ guide digestion through ___________________, a chemical reaction that breaks down substances by addition of water Enzymes are _______________ to carbohydrate, protein, and fat digestion Hormones Assist in Digestion Hormones are released into the bloodstream to _________________________________ that contain the _______________ protein for that given hormone ____________________________________: Hormones bind to the receptor on the cell membrane for activation Key hormones involved in digestion: Accessory Organs Produce, Store, and Secrete Chemicals that also Aid in Digestion Accessory Organ: ___________________ Gallbladder stores __________________, a greenish fluid, produced by the liver _________________ signals the gallbladder to release bile Bile _________________________ the lipids Lipids are dispersed into smaller globules and become more accessible to digestive enzymes Accessory Organ: _________________ Manufactures, holds, and secretes ____________________________________ Stores enzymes in the _____________________ form _____________________________ digests carbohydrates _____________________________ digests fats _________________________ digests proteins ________________ and ___________________ (hormones) are produced to regulate blood glucose _______________________ is secreted to neutralize chyme Accessory Organ: ______________________ The liver is one of the most important organs in the body ____________________ chemicals for metabolism __________________ bile for emulsification of fats Receives the products of digestion via the portal vein (also called the portal venous system) ____________________ glucose from glycogen stores Stores vitamins _____________________________ blood proteins Absorption Process of taking molecules ________________ a cell membrane and into cells of the body A small amount of absorption occurs in the ________________ Most absorption of nutrients occurs in the ____________________________ Types of Absorption Passive Diffusion _____________________________ - nutrients simply pass through the enterocytes and into the blood stream without the use of a __________________ or ______________________ Going from ______________ to ______________________ concentration No ____________________ expended Facilitated Diffusion Requires a _____________________________ Going from ___________________ to _______________________ concentration No ______________________ expended Active Transport Requires ___________________ and a _____________________ carrier to transport nutrients Endocytosis ________________________________, the lining of the GI tract, has special structures to facilitate absorption _________________ are folds in the lining that allow it to absorb more nutrients ___________________ are absorptive cells in the villi Capillaries and a ____________________ (small lymph vessel) are inside each villus The brush border is composed of ____________________, which greatly increase the surface area What happens to the nutrients after absorption? Transport of Nutrients and Wastes _____________________ travels through the cardiovascular system _____________________ travels through the lymphatic system ___________________ pick up most lipids and fat-soluble vitamins ___________________ nodes are clusters of immune cells that filter microbes and other harmful agents Digestive Disorders ____________________ (burping) is primarily caused by swallowed air, eating too fast, improperly fitted dentures, and chewing gum ____________________ (intestinal gas) is a normal process that may be caused by Foods rich in fiber, starches, and sugar Bacteria that act on partially digested carbohydrates The fat substitute olestra and sugar alcohols Beano can offer some relief The lining of the stomach is designed to cope with hydrochloric acid, but other regions of the GI tract are not ____________________ is caused by hydrochloric acid in the esophagus ____________________________________________ (GERD) is painful, persistent heartburn Causes of GERD include Hiatal hernia Cigarette smoking or alcohol use Being overweight Pregnancy Chocolate, citrus, spicy or fried foods Large high-fat meal Lying down soon after a meal _______________________ are areas of the GI tract that have been eroded by HCL and pepsin Bacterium ___________________________ plays a key role in development of both gastric and duodenal ulcers ___________________________________ is a cluster of GI symptoms (gas, pain, diarrhea) that occur following consumption of a particular food _______________________________ is a hypersensitivity reaction of the immune system to a particular component (usually a protein) in a food ____________________________ (celiac sprue) Damaged small intestine lining (decreased villi and enzymes) reduces nutrient absorption Offending component is gliadin (a protein in ________________), which is found in wheat, rye, and barley __________________ reflex is triggered when substances stimulate brain cells to signal "backwards" peristalsis _____________________________ (CVS) is a chronic condition of recurring cycles that can last for hours or days _________________________ This inflammatory bowel disease can affect any area of the GI tract Possible cause is immune system reaction to a virus or bacteria Symptoms include diarrhea, abdominal pain, rectal bleeding, weight loss, fever, anemia Children can experience delayed growth _______________________________ Chronic disease characterized by inflammation and ulceration of the mucosa, the innermost lining of the colon Possible cause is an immune response to a virus or bacteria Symptoms are similar to Crohn's disease Although not caused by food, patients may have to avoid foods that cause GI discomfort _______________________________ Frequent passage of loose, watery stools Usually caused by infection of the GI tract, stress, food intolerances, reactions to medications, or bowel disorders Can lead to severe dehydration More dangerous for children and the elderly ____________________________—common concern; also called ________________________ ______________________________ Infrequent hard, small, difficult-to-pass stools Prevention includes increasing fiber-rich foods and fluids, and regular exercise ______________________________ (_______) is a disorder that interferes with normal colon function Symptoms include abdominal cramps, bloating, and either diarrhea or constipation Associated with stress, caffeine, large meals, chocolate, alcohol, dairy, wheat Treatment includes stress management, smaller meals, high-fiber diet, fluids, and regular physical activity Probiotics and Human Health ______________________ Live microorganisms which, when administered in adequate amounts, confer a health benefit on the host Bacteria in the Colon Protection against invading microorganisms Synthesizing vitamins (Vit K) Reduce ulcers Reduce inflammation Prevention of diarrheal diseases Intro to Chemistry Chemistry _____________________ The smallest “piece” of an element that retains the characteristics of that element. Composed of 3 subatomic particles: Draw the structure of the atom and describe the characteristics of the subatomic particles How do we calculate the # of subatomic particles in each atom? Atomic _________________ # _____________ in nucleus of an atom (establishes identity of the atom) Since most atoms are electrically neutral, atomic number indicates # of electrons as well. Atomic _____________________ # __________________ plus # ___________________ in nucleus of an atom How can we determine the number of neutrons in an atom? Do all carbon atoms have the same number of protons? Do all carbon atoms have the same number of neutrons? ___________________________ Atoms having the same number of protons, but differing numbers of __________________. Ex. Carbon isotopes carbon 12 (12C) 6 neutrons carbon 13 (13C) 7 neutrons carbon 14 (14C) 8 neutrons Molecule An accumulation of ________________ of different types to form a specific association. Smallest piece of a _____________________ that retains characteristics of that _____________________. Examples: 4CO2 4 molecules of carbon dioxide 2C6H12O6 2 molecules of glucose 6O2 6 molecules of oxygen How do they come together? Chemical Bonds Type of bond formed is determined by the number of ___________________ electrons in the interacting atoms [_____________ rule]. ____________________ bonds - form when atoms ___________________ electron pairs. strongest type of bond ___________________ bonds - form when oppositely charged _______________ are attracted to each other. weaker than covalent bonds form salts Ex. NaCl ____________________ bonds - form when opposite charges on two ________________ are attracted to each other. weakest type of bond* Chemical Reactions When compounds or set of compounds (________________) is converted into another compound or set of compounds (_________________). It is usually accompanied by a release or absorption of energy Dehydration vs. Hydrolysis Dehydration reactions A ______________ molecule is _______________ Hydrolysis reactions A ______________ molecule is _______________ Oxidation vs. Reduction Oxidation: _________________ of ___________________ (in atoms) Reduction: __________________ of ____________________ Acids and Bases ___________ – substances that add H+ to a solution ___________ – substances that remove H+ from a solution What does pH scale measure? Carbohydrates: Plant-Derived Energy Nutrients What Are Carbohydrates? One of the three _____________________ Important source of ___________________ for all cells ________________ energy source for nerve cells Composed of ______________, ___________________, ________________ Good sources: fruits, vegetables, grains Glucose The most abundant carbohydrate Produced by plants through _________________________ Simple carbohydrates Contain _______ or ___________ molecules Commonly referred to as ___________________ ____________________ contain __________ molecule ____________________ contain __________ molecules Complex carbohydrates ___________________ contain 3 to 10 monosaccharides Most _______________________ consist of hundreds to thousands of glucose molecules Starch, glycogen, most fibers Starch ______________ store carbohydrates as starch ________________—straight chain of glucose _____________________—branched chain of glucose Sources: grains, legumes, fruits, vegetables Glycogen Storage form of glucose for ____________________ (humans) Not found in _______________ and therefore not a source of dietary carbohydrate Stored in the liver and muscles Fiber Composed of long polysaccharide chains ___________________ fibers are non-digestible parts of plants ___________________ fibers are non-digestible forms of carbohydrates extracted from plants or manufactured in a laboratory and have known health benefits ______________ fiber = Dietary fiber + Functional fiber _______________ fibers _________________ in water; viscous and gel-forming Fermentable, digested by intestinal bacteria Associated with risk reduction of cardiovascular disease and type 2 diabetes Examples: pectin, gum, mucilage Found in citrus fruits, berries, oats, beans ________________ fibers Do not dissolve in water, ___________________ Cannot be fermented by bacteria in the colon Promote regular bowel movements, alleviate constipation, and reduce diverticulosis Examples: lignins, cellulose, hemicelluloses Good sources: whole grains, seeds, legumes, fruits, and vegetables Carbohydrate Digestion Digestion breaks down most carbohydrates into _________________________ __________________________ Enzyme that begins carbohydrate digestion in the mouth Breaks starch down to __________________ Carbohydrate digestion does ________ occur in the stomach Stomach acids __________________ salivary amylase Most chemical digestion of carbohydrates occurs in the small intestine ______________________________ Enzyme produced in the pancreas and secreted into the small intestine Digests starch to ________________ Additional enzymes in the microvilli digest disaccharides to monosaccharides Monosaccharides are ___________________ into the cells lining the small intestine and then enter the bloodstream All monosaccharides are ___________________ to glucose by the liver Glucose circulating in the blood is our ________________ energy source Excess glucose is stored as ____________________ in the liver and muscles We do not have the enzymes necessary to digest _______________ _______________ in the large intestine can break down some fiber Most fiber remains undigested and is excreted in the ________________ Blood Glucose Regulation Blood glucose must be closely regulated Hormones control blood glucose levels: Blood Glucose Regulation: ________________________ Secreted by _________ cells of the pancreas Stimulates glucose transporters (______________________) to help take glucose from the blood across the cell membrane Stimulates the liver to take up glucose and convert it to ____________________ Blood Glucose Regulation: _______________________ Secreted by ____________ cells of the pancreas Stimulates the liver to convert glycogen to glucose Stimulates _______________________, the production of glucose from amino acids Blood Glucose Regulation: _____________________ and _____________________ Secreted by the adrenal glands and nerve endings when blood glucose is low Increase glycogen breakdown in the liver, releasing glucose into the blood Responsible for our "fight-or-flight" reactions to danger Blood Glucose Regulation: _________________ and ______________________ Secreted by the adrenal glands to act on the liver, muscle, and adipose tissue Cortisol increases gluconeogenesis and decreases muscle glucose use Growth hormone decreases muscle glucose uptake, increases fatty acid mobilization and use, and increases liver glucose output Blood Glucose Regulation: __________________ Index A food's potential to raise blood glucose Foods with a ________________ glycemic index cause a sudden surge in blood glucose, triggering a large increase in insulin, which may be followed by a dramatic fall in blood glucose Foods with a low glycemic index cause low to moderate fluctuations in blood glucose Not always easy to predict Food's absorption rate varies with type of carbohydrate, preparation methods, and its fat and fiber content Most foods are eaten in combination in a meal Blood Glucose Regulation: _______________________ Load Used to determine the effect of a food on a person's glucose response Grams of carbohydrates in a food are multiplied by the glycemic index Glycemic index and glycemic load remain controversial Evidence of health benefits is weak Value of Lower Glycemic Index Less fluctuations in blood glucose Risk reduction for heart disease and colon cancer High fiber intake helps to improve fat levels in the blood (higher HDL and lower LDL) Foods with lower glycemic index: Beans, fresh vegetables, whole wheat The Role of Carbohydrates __________________ Each gram of carbohydrate: ___kcal Red blood cells use only glucose for energy Both carbohydrates and fats supply energy for daily activities Glucose is especially important for energy during exercise Ketosis Fat breakdown during fasting forms ______________ Excess ketones increase blood acidity and cause _______________________________ Sufficient energy from carbohydrates prevents ketone production as alternate energy source Carbohydrates Spare Protein ___________________________ occurs when a diet is deficient in carbohydrate The body will make its own glucose from protein Amino acids from these proteins cannot be used to make new cells, repair tissue damage, support the immune system, or perform any of their other functions Complex Carbohydrates Have Health Benefits Fiber May reduce the risk of _______________ cancer Helps prevent hemorrhoids, constipation, and other intestinal problems May reduce the risk of _________________________ May reduce the risk of heart disease May enhance weight loss May lower the risk of type 2 diabetes How Much Carbohydrate? Recommended Dietary Allowance (RDA) is 130 grams/day to supply adequate glucose to the brain Acceptable Macronutrient Distribution Range (AMDR) is 45% to 65% of daily calories Focus on fiber-rich carbohydrate foods Simple Carbohydrates Diets high in simple sugars: Can cause tooth decay May increase "________ cholesterol" May decrease "________ cholesterol" May contribute to obesity Complex Carbohydrates Most Americans eat too little complex carbohydrates ________________ foods are foods in which nutrients that were lost during processing have been added back so the food meets a specified standard Fortified foods have nutrients added that did not originally exist in the food (or existed in insignificant amounts) Fiber Adequate Intake (AI) for fiber 25 g per day for women 38 g per day for men, or 14 g of fiber for every 1,000 kcal per day It is best to get fiber from food (also a source of vitamins and minerals) An adequate fluid intake (at least 8 oz/day) with high-fiber diets is recommended Alternative Sweeteners Nutritive sweeteners Sucrose, fructose, honey, and brown sugar contain 4 kcal energy per gram Slow-absorbing sugar alcohols: 2−3 kcal/gm Non-nutritive (alternative) sweeteners Provide little or no energy Safe for adults, children, people with diabetes ______________________ 180-200x sweeter than sucrose Heat tolerable ______________________ K for potassium 200x sweeter than sucrose Not digested by the body Heat stable AKA Sunette ________________________ 180-200x sweeter than sucrose 4 kcals/g, but only a trace amount is needed to sweeten foods Not heat stable Complaints of sensitivity to aspartame headaches, dizziness, seizures, nausea, etc. Not recommended for people with phenylketonuria (PKU) ___________________________ 600 x sweeter than sucrose Heat stable Excreted in feces (small amount in urine) “Made from sugar so it tastes like sugar" __________________________ ~7000 –13000 times sweeter than sucrose Structure is similar to aspartame (but not a risk for PKU) Heat stable Safe for use by the general population (including children, diabetics, pregnant and lactating women) Used in a variety of products _________________________ 200 sweeter than sucrose extract from stevia plant Aka Truvia or Purevia Diabetes Inability to regulate blood glucose levels Types Type 1 diabetes Type 2 diabetes ______________________ diabetes Uncontrolled diabetes can cause nerve damage, kidney damage, blindness, and can be fatal ________________________ = higher-than-normal blood glucose levels Diabetes—Type 1 Accounts for 10% of all cases Body does not produce enough insulin Causes hyperglycemia (high blood glucose) Once known as juvenile-onset diabetes or insulin dependent diabetes mellitus (IDDM) May be an autoimmune disease Carbohydrate intake must be coordinated with insulin injections to maintain Blood-Glucose levels Diabetes—Type 2 _________________________ (insulin resistance): cells become less responsive to insulin _________________________: a cluster of risk factors that increase the risk for type 2 diabetes Once known as adult-onset diabetes Increasing in children and adolescents Cause is unclear, but genetics, obesity, and physical inactivity play a role Treat with weight loss, healthy eating, regular exercise, and, if necessary, medications Healthy lifestyle choices may prevent or delay the onset of type 2 diabetes Hypoglycemia Low blood glucose may cause shakiness, sweating, anxiety, weakness _______________ hypoglycemia: pancreas secretes too much insulin after a high-carbohydrate meal _______________ hypoglycemia: pancreas produces too much insulin, even when someone has not eaten Lactose ___________________ Insufficient enzyme lactase to digest the lactose-containing foods Symptoms: gas, bloating, cramping, diarrhea Extent of intolerance: mild to severe Persons with lactose intolerance may need to find alternate sources of calcium Lactose ______________________ Coping with lactose maldigestion Determine tolerated amount Eat dairy with fat Cheese and yogurt more easily tolerated Lactase pills Health Concerns: Dental Caries Tooth decay or dental cavities Infectious disease which damages the structures of Teeth Bacteria collect around the teeth and gums in a sticky, creamy-coloured mass called plaque Prevented by eating sugar-free products Personal hygiene care consists of proper brushing and flossing daily