1. Chapter 29
Nutrition & Digestion

2. Food as a Source of Nutrients
Your body needs nutrients from food to build tissue and do cellular work (energy)

3. Key Questions What materials do organisms need maintain homeostasis?
How do they obtain these materials?

4. Look at the table
on page 1 of
your notes…

5. Carbohydrates…

6. Organic
Found in bread, pasta, grains, cereals, fruit, candy

8. Function = ENERGY!
END PRODUCTS (building blocks)
monosaccharides (glucose)

9. Recall these molecular structures:

10. Lipids…

11. Organic
Found in fatty foods (meat, oils, nuts, avacados)

12. Function = Store
ENERGY!
END PRODUCTS: fatty acids and glycerol

14. Proteins…

15. Organic
Found in meat, fish, eggs, nuts, beans

17. Function = enzymes, hormones, muscle
END PRODUCTS
amino acids

19. Minerals…

20. Calcium, Copper, Iodine, Iron, Magnesium, Zinc, Phosphorus, Potassium
Inorganic ions
Found in all foods
Calcium, Copper, Iodine, Iron, Magnesium, Zinc, Phosphorus, Potassium

21. Function=help life processes
ex. Calcium-bones & teeth;
iron-hemoglobin
END PRODUCTS
Minerals are NOT broken down!

22. Vitamins…

23. Vitamin C – C6H8O6
Vitamin B5 – C9H17NO5
Vitamin A – C20H30O
Are vitamins organic??

24. Organic
Found in all foods

25. Function = coenzymes
END PRODUCTS:
Vitamins are NOT broken down!

26. Water…

27. Inorganic
Found in all foods

28. FUNCTION = needed for metabolism, 2/3 of body is water
END PRODUCTS:
Water is not broken down!

29. Minerals and water are different
from other
nutrients because
_______________
They are inorganic

30. The major elements found in nutrients are _____________
H, O, N, C, P, S
C HOPKINS CaFe Mg NaCl

31. 4 Stages of Food Processing
1. Ingestion
2. Digestion
3. Absorption
4. Elimination (egestion)

32. 1. Ingestion
The act of bringing food into the body (eating or drinking)
Importance: food enters internal spaces for digestion

33. 2. Digestion
Process of breaking food down into small molecules that can be absorbed
2 types of digestion…

34. a. Mechanical Makes food smaller by tearing, chewing, grinding
Increases surface area

35. b. Chemical Chemically changing food (by hydrolysis)
Large molecules broken down to small molecules
Enzymes are used

36. b. Chemical i. Intracellular – inside a cell (in a vacuole)
ii. Extracellular – outside a cell in a cavity (like our stomach)

37. 3. Absorption Nutrients entering the cells of an organism
Molecules must be small enough to cross cell membranes

38. 4. Elimination (egestion)
Undigested or indigestible materials leaving the organism (Feces)
Not the same as excretion

39. Read the story
on page 3

40. Digestion Occurs in a Tube
Food typically moves in one direction through a twisting tube as food is broken down

42. Organs of the
Digestive System…

43. Human Digestive System Overview
Alimentary Canal
(food passes through)
Mouth
Esophagus
Stomach
Small intestine
Large intestine
Accessory Organs
Pancreas
Liver
Gall Bladder

44. 1. Oral cavity ( mouth)
Location of Ingestion
Mechanical digestion – teeth
Chemical digestion - amylase

46. 1. Oral cavity ( mouth) Secretions – saliva contains
mucous for lubrication
salivary amylase – enzyme that begins the digestion of carbohydrates

47. 2. Pharynx Also called the throat
Junction of the digestive tract and the passageway of the lungs

48. 2. Pharynx Bolus – chewed up clump of food
Epiglottis – flap of cartilage that seals off the trachea when you swallow so food doesn’t enter it

50. Activity of the mouth and throat

51. 3. Esophagus
12 inch tube that carries the bolus of food from the mouth to the stomach

52. 3. Esophagus
Peristalsis - muscular contractions that pushes food to stomach
No Digestion occurs in the esophagus

54. 4. Stomach
Muscular sac; holds up to ~2L of liquid
Mechanical Digestion –muscles churn food by peristalsis mixing it with secretions.

56. 4. Stomach Secretions (lining of stomach):
Chemical Digestion –pepsin (enzyme) begins the digestion of proteins
Hydrochloric acid (made in stomach) makes an acid environment

57. “Valves” (sphincter) at each end are supposed to seal contents until mixed

58. 5. Small intestine Length = ~ 20 ft
Digestive function – Digestion of carbs, protein and lipids is completed in the SI.

59. 5. Small intestine Mechanical – peristalsis and bile (from liver)
Chemical –many digestive enzymes used in the SI:

60. 5. Small intestine
Secretions – from small intestine lining, pancreas and liver all used in SI peptidases - proteins amylase & maltase - carbohydrates lipase – lipids

61. 5. Small intestine
Absorption – digested nutrients (small molecules) are absorbed from the SI into the blood.

62. 5. Small intestine
Villi – fingerlike projections from the lining that increase surface area for absorption. Villi - contain small blood vessels

64. Villi in the Small Intestine
Capillaries

65. Glucose Amino Acids Glycerol Fatty Acids
List the materials that would be absorbed from the fluids of the small intestine into the villi:
Glucose
Amino Acids
Glycerol
Fatty Acids

66. Appendix:
Blind sac of tissue at the junction of the Small Intestine and Large Intestine.
Vestigial Structure
Function?

68. 6. Large Intestine Length ~ 1.5 meters No digestion occurs here
Water absorption from the food mass into the blood occurs in the LI

69. 6. Large Intestine
Vitamin K and some B vitamins are made in the LI (by bacteria) and absorbed into the bloodstream

70. 6. Large Intestine
Forms feces (solid waste) – that is temporarily stored in rectum and leaves body (egested) through the anus

71. Accessory Organs Page 6
Contribute to digestion but food does not travel through

73. Pancreas Secretes hydrolytic enzymes into the SI:
Amylase – digests carbohydrates
Proteases – digests proteins
Lipase – digests lipids

75. Liver
Makes bile which emulsifies lipids (mechanical digestion)

77. Gallbladder
Thin sac that stores bile and delivers it to the small intestine

80. Pharynx
Salivary Glands
Teeth
Mouth
Tongue
Salivary Glands
Epiglottis
Esophagus
Liver
Stomach
Gall Bladder
Pancreas
Bile Duct
Duodenum
Sm. Intest.
Lg. Intest.
Appendix
Rectum
Anus

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