Digestion S10

8/3/2019 Digestion S10

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Digestive System and NutritionDigestive System and Nutrition

OrgansOrgansProcess of DigestionProcess of Digestion

NutritionNutrition



Path of Food through the Digestive SystemPath of Food through the Digestive System

mouthpharynx

esophagus

stomach

small

intestinelarge

intestine

anal canal

Produces

peptidases,

maltase,

lactase

Produces

pepsin, HCl

Peristalsis: Muscular contractions that move food through the digestive systemPeristalsis: Muscular contractions that move food through the digestive system



Accessory Organs and Glands Accessory Organs and Glands

salivary

glands

liver

pancreasgallbladder

Produce

salivaryamylase Produces

pancreatic

amylase,

trypsin,

lipaseProduces

bile

Stores bile



Process of Digestion and AbsorptionProcess of Digestion and Absorption MouthMouth

± ±Teeth chew foodTeeth chew food

into smaller piecesinto smaller pieces

± ±Salivary amylaseSalivary amylase

(enzyme in saliva)(enzyme in saliva)begins starchbegins starch

digestiondigestion

± ±Tongue mixes foodTongue mixes foodwith saliva to formwith saliva to form

bolus to bebolus to be

swallowedswallowed

Starch in bun has

been broken into

smaller chains of

sugars



Process of Digestion and AbsorptionProcess of Digestion and Absorption

StomachStomach ± ±HCl acid unfoldsHCl acid unfolds

proteinsproteins

± ±Pepsin (enzyme)Pepsin (enzyme)begins proteinbegins protein

digestion, breakingdigestion, breaking

some peptide bondssome peptide bonds

Protein in beef has

been broken into

smaller chains of

amino acids

gastric pit

gastric gland

esophagus

sphincter

pyloric

sphincter

cells that

secrete

gastric

juice

muscularis

layer has

three layers

of muscle

mucosa layer

has rugae

Contains pepsin,

HCl, mucus




Small IntestineSmall Intestine

± ± Large surface area dueLarge surface area due

to numerous villito numerous villi

± ± Bile emulsifies lipidsBile emulsifies lipids

± ± Pancreatic and intestinalPancreatic and intestinalenzymes digestenzymes digest

car bohydrates, lipids,car bohydrates, lipids,

proteinsproteins

± ± Amino acids and sugars Amino acids and sugarsabsor bed into bloodabsor bed into blood

± ± Lipids absor bed intoLipids absor bed into

lymphatic systemlymphatic system

Car bohydrate,

Protein and Fat

have been digestedand absor bed

lacteal

venule

arteriole

villus

lymphatic

vessel

blood

capillaries



Digestion occurs by Hydrolysis of MacromoleculesDigestion occurs by Hydrolysis of Macromolecules

carbohydrate

pancreatic amylase

maltase

glucose

pH = basic pH = basicpH = basic

protein

trypsin

peptides

lipasepeptidase

amino acids

blood capillaryblood capillary

bile salts fat globules

Carbohydrate digestionCarbohydrate digestion Protein digestionProtein digestion Fat digestionFat digestion

+

emulsification

droplets

cell of

intestinal

villus

lymphatic

capillary

Hydrolysis:

chemical

separation of

subunitshydrolysis

Hydrolysis

Emulsification: physical

dispersion of lipids into

smaller droplets




Large IntestineLarge Intestine

± ± Absor bs water Absor bs water

± ± Absor bs salts (minerals) Absor bs salts (minerals)

± ± Ab

sor b

s some vitamins Ab

sor b

s some vitamins ± ±Stores waste for later Stores waste for later

eliminationelimination

Calcium fromcheese has been

absor bed. Fiber

from tomatoes and

lettuce remains.



Distribution and Use of NutrientsDistribution and Use of Nutrients

Liver Liver

± ± regulates nutrient entry intoregulates nutrient entry into

bloodblood

± ± detoxifies blooddetoxifies blood

± ± stores iron and fatstores iron and fat--solub

lesolub

levitaminsvitamins

± ± makes plasma proteinsmakes plasma proteins

± ± stores and releases glucosestores and releases glucose

± ± produces urea from amino acidsproduces urea from amino acids ± ± produces bileproduces bile

± ± destroys old red blood cellsdestroys old red blood cells

± ± helps regulate blood cholesterolhelps regulate blood cholesterol



Applying Your Knowledge Applying Your Knowledge

A. A. Where are fats digested?Where are fats digested?

B.B. Where do proteins unfold?Where do proteins unfold?C.C. Where does starch digestion begin?Where does starch digestion begin?

D.D. Where is water absor bed?Where is water absor bed?

1.1. StomachStomach2.2. MouthMouth

3.3. Large IntestineLarge Intestine

4.4. Small IntestineSmall Intestine



Nutritional RecommendationsNutritional Recommendations

MacronutrientsMacronutrients

± ± Car bohydrateCar bohydrate

± ± FatFat

± ± ProteinProtein

Water Water

MicronutrientsMicronutrients

± ± VitaminsVitamins ± ± MineralsMinerals

Use fats in small amounts



Car bohydrates: DietaryCar bohydrates: Dietary

RecommendationsRecommendations 58% of calories from car bohydrates58% of calories from car bohydrates

No more than 10% of calories from simple,No more than 10% of calories from simple,

refined sugarsrefined sugars EmphasizeEmphasize

± ± Complex Car bohydratesComplex Car bohydrates StarchStarch

Fiber (cellulose)Fiber (cellulose)

± ± NaturallyNaturally--occurring simple car bohydratesoccurring simple car bohydrates Fructose from fruitFructose from fruit

Lactose from milkLactose from milk



Fats: Dietary RecommendationsFats: Dietary Recommendations

<< 30% of calories from fats30% of calories from fats

<< 10% of calories from saturated fats10% of calories from saturated fats

Limit cholesterol to 300 mg/dayLimit cholesterol to 300 mg/day

Avoid ³trans´ fatty acids in partially Avoid ³trans´ fatty acids in partially

hydrogenated productshydrogenated products

EmphasizeEmphasize

± ±Unsaturated fatty acids fromUnsaturated fatty acids fromvegetables,vegetables, fish, legumes,fish, legumes, and nutsand nuts

± ±Oils: monoOils: mono-- or polyunsaturatedor polyunsaturated



Proteins: DietaryProteins: Dietary

RecommendationsRecommendations 12% of calories from proteins12% of calories from proteins

8 essential amino acids obtained8 essential amino acids obtainedfromfrom

± ±Lean sources of animal proteinLean sources of animal protein

± ±Complementary plant proteinsComplementary plant proteins Beans + GrainsBeans + Grains

Beans + SeedsBeans + Seeds



VitaminsVitamins

Organic compounds used in metabolicOrganic compounds used in metabolicreactions as coenzymes or reactions as coenzymes or

antioxidantsantioxidants Water Soluble: B vitamins, CWater Soluble: B vitamins, C

Fat Soluble: A, D, E, KFat Soluble: A, D, E, K

Adequate amounts come from a varied Adequate amounts come from a varieddiet that includes vegetables and fruitsdiet that includes vegetables and fruits

May prevent cancer and cardiovascular May prevent cancer and cardiovascular diseasedisease



MineralsMinerals

Inorganic substances required by theInorganic substances required by thebodybody

Macrominerals needed in largeMacrominerals needed in largeamounts, eg. calciumamounts, eg. calcium

Microminerals needed in smaller Microminerals needed in smaller

amounts, eg. ironamounts, eg. iron May need to emphasize certain foodsMay need to emphasize certain foods

to obtain iron or calciumto obtain iron or calcium

May need to limit foods high in sodiumMay need to limit foods high in sodium



Applying Your Knowledge Applying Your Knowledge

A. A. Which one is a mineral?Which one is a mineral?

B.B. Which macronutrient should supply theWhich macronutrient should supply thegreatest number of calories in the diet?greatest number of calories in the diet?

C.C. Which one may protect against cancer?Which one may protect against cancer?

1.1. CalciumCalcium

2.2. Vitamin CVitamin C

3.3. LipidLipid

4.4. Car bohydrateCar bohydrate

5.5. ProteinProtein



Reading aReading a

Nutrition LabelNutrition Label

More info atMore info at

http://www.fda.govhttp://www.fda.gov



Calorie Percentage CalculationsCalorie Percentage Calculations

5 x 4/250 = 0.080 x 100 = 8.0%5 x 4/250 = 0.080 x 100 = 8.0%

5 x 4/250 = 0.080 x 100 = 8.0%5 x 4/250 = 0.080 x 100 = 8.0%

31 x 4/250 = 0.496 x 100 = 49.6%31 x 4/250 = 0.496 x 100 = 49.6%

12 x 9/250 = 0.432 x 100 = 43.2%12 x 9/250 = 0.432 x 100 = 43.2%

3 x 9/250 = 0.108 x 100 = 10.8%3 x 9/250 = 0.108 x 100 = 10.8%

Number of grams

Caloric value

Total calories

T h e s e s h o u

l d a d d t o 1 0

0 % .

Digestion S10

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