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Nutrition in Humans

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NutrientsPart I Nutrients are the usable portions of foods What are nutrients used for? 1. Energy Sources 2. Building or Repair of cell structure 3. Regulate metabolic processes

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6 Main Groups 1. Carbohydrates (bread, pasta, potatoes, candy) 2. Proteins (beef, fish, milk, peas, nuts) 3. Fats & Oils (butter, bacon, vegetable oil) 4. Water (most foods contain water) 5. Minerals (calcium, iron, sodium, chlorine) 6. Vitamins ( A, B 1, B 2, Niacin, B 12, C, D, K)

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Which are organic and which are not? Organic 1. Carbohydrates 2. Proteins 3. Fats N Oils 4. Vitamins Inorganic 1. Water 2. Minerals

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What about What we cant digest Roughage: indigestible food Examples: fibrous matter (cell wall) in fruits, vegetables, and whole grains Benefit: provides bulk to be worked on by muscles, keeps things moving forward

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Carbohydrates Subunit: Saccharides 1. Monosaccharides:1 (simple sugars, glucose) 2. Disaccharides: 2 (sucrose and maltose) 3. Polysaccharides: 3 or more (Starch in plants and Glycogen in animals)

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Regents Question Most of the starch stored in the cells of a potato is composed of molecules that originally entered these cells as (1) enzymes (2) simple sugars (3) amino acids (4) minerals

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Why can glucose diffuse through the cell membrane and Starch can not? Glucose is a monosaccharide and much smaller than the polysaccharide of Starch

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Proteins Subunit: Amino Acids (NH 2 = amino group COOH = carboxyl acid)

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Regents Question Two proteins in the same cell perform different functions. This is because the two proteins are composed of (1) chains folded the same way and the same sequence of simple sugars (2) chains folded the same way and the same sequence of amino acids (3) chains folded differently and a different sequence of simple sugars (4) chains folded differently and a different sequence of amino acids

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Regents Question Which statement concerning proteins is not correct? (1) Proteins are long, usually folded, chains. (2) The shape of a protein molecule determines its function. (3) Proteins can be broken down and used for energy. (4) Proteins are bonded together, resulting in simple sugars.

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Proteins The Human body need 20 different types of Amino Acids 12 of the 20 humans can synthesize (produce) 8 of the 20 humans can not, these 8 are called Essential amino acids (Isoleucine, Leucine, Lysine, Methionine, L- Phenylalanine, Threonine, Tryptophan and Valine)Isoleucine, Leucine,LysineValine

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If proteins come mostly from meat, how do vegetarians get the 8 essential? There are 2 types of proteins 1. Complete Protein: contains all essential amino acids 2. Incomplete Protein: missing one or more essential amino acids So to answer the question: a vegetarian can eat a combination of incomplete proteins to provide all essential amino acids (ex. Rice and Beans)

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What happens if you are missing one of the essential 8? You would get a protein-deficiency disease. Example: Populations in Africa diet consist of cornmeal (incomplete protein) lacks Tryptophan. These children have a disease called Kwashiorkor (tired and abnormal growth)

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Fats (Lipids) Synthesized in body from Fatty acids and Glycerol Represents stored energy Together with proteins synthesize the cell membrane

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Fats (Lipids)

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Bad Fat Saturated Fat: Usually solid at room temperature, No Double Bonds, lead to cholesterol deposits in blood vessels

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Good Fat Unsaturated Fat: consists of oils (liquid at room temperature), one or more Double Bonds

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Minerals Important inorganic material (helps in structure of cells and tissues) Calcium (Ca): strong teeth and bones, milk & eggs Iron (Fe): helps in formation of red blood cells (red pigment), liver, meats & vegetables Sodium (Na): needed for proper cell function, table salt

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Vitamins Like minerals, perform many functions Especially important growth of children In adults repair and maintain healthy body functions Unable to be synthesized by humans

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Vitamins A: healthy eyes & skin, green and yellow vegetables B1: growth and appetite, meats, seafood, milk B12: production of red blood cells, liver & green vegetables C: healthy teeth, gums, and blood vessel repair, fruits D: growth and maintenance of bones, produced in skin exposed to sunlight & fortified milk K: blood clotting, liver function, synthesized by bacteria in body

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Water Excellent solvent (dissolves many compounds) Main component of fluid transport (blood) Many chemical reactions take place Lubricant for joints and digestive system Cools body by sweat evaporation Lost by breathing, urination, and elimination

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What is a calorie? The amount of heat needed to raise 1mL of water by 1 C 0 Unit of measurement for energy value in food Calorimeter: tool used to measure calories in foods

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Food Additives Saccharin: artificial sweetener Nitrites: protect food from bacterial decay and provide red color, found in bacon hotdogs, and deli meats Monosodium glutamate (MSG): flavor enhancer

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The Digestive System PartII

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What is the Digestive System? The alimentary canal (coiled tube which ingested materials move in one direction) and digestive glands make up the digestive system Hydrolysis

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What are the functions of the Digestive System? There are 3 main functions of the Digestive system 1. Ingest foods (eat) 2. Breakdown foods so nutrients can be absorbed 3. Eliminate (egestion) what can not be digested

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Regents Question Which order of metabolic processes converts nutrients consumed by an organism into cell parts? (1) digestion absorption circulation diffusion synthesis (2) absorption circulation digestion diffusion synthesis (3) digestion synthesis diffusion circulation absorption (4) synthesis absorption digestion diffusion circulation

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When does digestion start? As soon as we place food in our mouth. Mechanical and Chemical digestion occurs Mechanical digestion = Chewing Chemical digestion= Saliva

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Digestion in the Mouth Mucus Glands: lubricant for food in the form of mucus (allows food to travel smoothly) Saliva Glands: contains amylase (enzyme) which breakdown starch into maltose Polysaccharide (starch) to a Disaccharide (maltose)

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From your mouth to your Esophagus Swallowing: coordinated reflex action that moves food to the esophagus During swallowing the trachea (windpipe) moves upward against the epiglottis (flap)

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Esophagus Food is moved from the mouth to the stomach The movement is called Peristalsis: muscle contractions and relaxations (moves in waves, like pushing a tube of toothpaste)

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Stomach Muscular organ that churns food and initiates protein digestion (balloon like, expands when full and shrinks when empty

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Stomach (Gastric Juices) Gastric Glands: located on the inner lining of the stomach Contains peposinogen and hydrochloric acid HCl (keeps pH at 2 and kills off bacteria) Acidic environment favorable for pepsin (enzyme) to breakdown proteins Rennin: an enzyme that changes liquid proteins into a solid state (curdles milk proteins)

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Stomach (final product) The process takes about 2 to 24 hours (depending of the foods present) Chyme: mixture of saliva, gastric juices, and water

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Which organs of the digestive system never in contact with food? 1. Liver: secretes bile (aids in digestion of fats) emulsification (makes small globules of fat from large ones) 2. Gallbladder: bile is stored here and transport to small intestine via bile duct 3. Pancreas: pancreatic juices (enzymes) Proteases= protein digestion Amylase= carbohydrate digestion Lipase= fat digestion

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Liver, Gallbladder, & Pancreas

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Small Intestine 1. Longest part of digestive tract (7m) 2. Called small because of diameter (6.5 cm) 3. Most digestion and absorption occurs here

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Absorption in Small Intestine Villi: tiny projectiles on the inner surface of small intestine There are enough villi in your small intestine to cover a tennis court (large surface area)

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How do the nutrients leave the Small intestine? 1. Diffusion 2. Villi only 1 cell thick 3. Amino acids and simple sugars enter capillaries 4. Fats enter lacteal (lymph vessel)

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Small Intestine is an excellent example of adaptation 1. Muscles contract to mix liquids and bring them to villi 2. Great length and folds provide large surface area for absorption 3. Villi provides large surface area (ten times greater than skin) 4. Thin membrane allows for easy diffusion of nutrients

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Large Intestine No digestion occurs here Water absorption Contains bacteria which produce vitamins Eating yogurts help replenish lost bacteria

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Time of Digestion Mouth: 5-10 sec Esophagus: 10 sec Stomach: 2 to 24 hours Small Intestine: 3 to 4 hours Large Intestine: 18 hours to 2 Days

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Elimination (egestion) Feces or waste is stored in the rectum (lower part of large intestine) Feces leaves our body through the anus

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Problems in Digestion What do you call a hole in your stomach? Ulcer: occurs when HCl (hydrochloric acid) and pepsin are in direct contact with the stomach lining. (little to no Mucus present)

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Why cant I Poop? Constipation: occurs in the Large intestine, happens when too much water is absorbed and the feces hardens What is the opposite of constipation? Diarrhea: Not enough water in absorbed in the Large intestine and the feces remains soft and watery (may be a symptom of infection or stress)

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Appendicitis Inflammation of the appendix (located where the small intestine meets the large intestine) Symptoms: abdominal pain, nausea, and fever Surgery usually needed to remove before rupture

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Gallstones Harden deposits that form in the gallbladder (deposits may block the bile duct, causing pain)