Nutrition in Humans

1. Nutrition in Humans

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

3. 6 Main Groups • Carbohydrates (bread, pasta, potatoes, candy) • Proteins (beef, fish, milk, peas, nuts) • Fats & Oils (butter, bacon, vegetable oil) • Water (most foods contain water) • Minerals (calcium, iron, sodium, chlorine) • Vitamins ( A, B1, B2, Niacin, B12, C, D, K)

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

5. What about What we can’t 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

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

7. 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

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

9. Proteins • Subunit: Amino Acids (NH2 = amino group COOH = carboxyl acid)

10. 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

11. 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.

12. 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)

13. If proteins come mostly from meat, how do vegetarians get the 8 essential? • There are 2 types of proteins • Complete Protein: contains all essential amino acids • 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)

14. 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)

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

16. Fats (Lipids)

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

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

19. 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

20. 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

21. 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

22. 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

23. What is a calorie? • The amount of heat needed to raise 1mL of water by 1 C0 • Unit of measurement for energy value in food • Calorimeter: tool used to measure calories in foods

24. 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

25. The Digestive System PartII

26. 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

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

28. 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

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

30. 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)

31. 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)

32. 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)

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

34. 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)

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

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

37. Liver, Gallbladder, & Pancreas

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

39. 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)

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

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

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

43. 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

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

45. 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)

46. Why can’t 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)

47. 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

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