1. TOPIC: Nutrition AIM: What are the parts and functions of the digestive system?

2. 2 Types of
Digestion

3. Large pieces of food are physically broken down into smaller pieces
1.Mechanical
Digestion
Large pieces of food are physically broken down into smaller pieces

4. Increases surface area of food to speed up chemical digestion

5. Makes food easier to swallow
Example: Teeth

6. Complex molecules are broken down into smaller molecules
2.Chemical
Digestion
Complex molecules are broken down into smaller molecules

7. HOW?
By using digestive enzymes

8. Carbs (starches)  simple sugars (glucose)

9. Proteins  amino acids

10. Digestive
System
One way tube

11. You are a tube inside a tube…
The tube starts here:
And although there are a few twists and turns along the way…
Anything that goes into the mouth does not become part of the body until it is absorbed (taken in) in a part called the small intestine.
It comes out here:

12. Function
Breakdown of food into pieces small enough for nutrients to diffuse into cells

13. Path of
Food

14. 1. Mouth (oral cavity) TEETH Incisors Canine Premolars Molars
“Wisdom” tooth
Tongue
Salivary glands
Opening of a salivary gland duct

16. Mechanical digestion (teeth)

17. Saliva – produced by salivary glands
a. moistens food

19. b. Chemical digestion
Enzyme that digests starch  sugar

20. Closes over windpipe when you swallow
Epiglottis
Small flap of tissue
Closes over windpipe when you swallow
To prevent choking

23. 2. Esophagus
esophagus

24. Connects mouth to stomach
NO DIGESTION

25. Peristalsis: muscular movement that pushes food along

28. 3. Stomach
- Where protein digestion begins

29. Where gastric juice is made.

30. Gastric Juice contains:
1.Hydrochloric acid  makes stomach acidic

31. 2. Enzymes that
chemically breaks down PROTEINS

33. b. Mucus = protects stomach wall

34. c. Mechanical digestion = food churned and mixed  chyme (mixture of partially digested food)

35. 4. Small intestine

36. Length = 4-7 meters

37. Where most chemical digestion occurs
ALL digestion ends after the first part of the small intestine called the Duodenum. In the 2nd part
Of the SI, Absorption of Nutrients Occurs.

38. Intestinal juice =
Contains enzymes that digest food

39. Food DOES NOT pass through these organs
Accessory
organs
Food DOES NOT pass through these organs
Help the SI

40. Liver
Stomach
Gall bladder
Duodenum
Pancreas

41. Liver

42. Produces bile
Bile travels to SI

43. Emulsification of fats  breaks down fat into smaller droplets
Big fat droplet

45. Gall Bladder

46. Stores bile

48. Pancreas

49. Makes pancreatic juice  into SI
Contains enzymes to chemically digest food

52. Villi

53. Rest of small intestine lined with VILLI (tiny folds)

54. Villi
Outer wall
Inner wall
Pathway for Food 54

55. Where nutrients diffuse (are absorbed) into blood

58. Increase surface area for nutrient absorption

60. 5. Large intestine

61. NO DIGESTION
Reabsorbs water
Forms feces (undigested food)
Contains bacteria (make vitamins)

62. If you squeezed out all of the bacteria that lives in your intestines, you could almost fill up a coffee mug. Anyone want a sip?

64. 6.
Rectum
Last part of LI
Stores feces

65. 7. Anus
Where feces is egested

68. Did you know… Your teeth started growing 3 months before you were even born The hardest substance in your body is the enamel on your teeth As you are sitting there listening, more than 100 million germs are swimming, feeding, reproducing, and making waste in the area behind your lips. In your mouth there are more living things than there are people in Australia and Canada combined…

69. REVIEW
1. Where does mechanical digestion begin? How?
2. Where does chemical digestion begin? How?
3. Where does chemical digestion end?
4. Where does most chemical digestion occur?
5. What is the function of the liver?
6. What are nutrients absorbed once food has been completely broken down.

70. Did you know....
An adult esophagus (also called gullet) ranges from 10 to 14 inches in length, and 1 inch in diameter
We make 1 to 3 pints of saliva a day
An adults stomach can hold approximately 1.5 liters of material
Food sloshing in the stomach can last 3-4 hours
The stomach's wall is lined with three layers of powerful muscles

71. Did you know....
The Average human being consumes about 500kg of food per year.
Within the colon, a typical person harbors more than 400 distinct species of bacteria
On average, the stomach produces 2 liters of Hydrochloric Acid (HCl) daily

72. Did you know....
A full grown horse’s coiled up intestines are 89 feet long
Food stays in your stomach for 2 to 3 hours
Americans eat about 700 million pounds of peanut butter.
Americans eat over 2 billion pounds of chocolate a year.
In your lifetime, your digestive system may handle about 50 tons!!

73. Did you know....
What you ate for breakfast, that was not digested will come out in about 48 hours-normally.
From intake to outlet, the digestive tract is about thirty feet long