Download xCh 8 digestion nutr

Ch 8 Digestive System & Nutrition
Next week in lab:
Diet analysis
 Record everything you eat or drink–and the
amount–for 24 hr (1 day)
 Analyze your diet using fitday.com
 Print out & bring to lab
1.
2.
3.
Food list
Calories table & pie chart
Nutrition table with %RDA values
 See details on my website
 Bring a nutrition facts label from a snack food
 We’ll do the worksheet in lab
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Food Processing: 4 stages
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Digestion: A Closer Look
 Mechanical digestion
 Begins the process
 Involves physical processes
like chewing
 Another word for eating = …
 Breakdown into smaller molecules = ..
 Uptake of molecules by cells lining the digestive
tract = …
 Breakdown of food by digestive
enzymes = …
 Disposal of undigested materials = …
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Why is Digestion Important?
 Digestion breaks
down food:
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Foods are Digested by Hydrolysis
Protein
Amino acid
OH
 Molecules small
enough for cells
to absorb
H
Enzyme
(pepsin)
Carbohydrate
H2 O
Cheese protein
(a polymer of amino acidsAmino acid
in a specific sequence) monomer
Breakdown of protein
by human digestive
system
Amino acids
 Monomers that
can be
recombined into
new molecules
H2 O
Absorption of amino acids by cells lining the small
intestine; transport via bloodstream to other cells
Human protein
Sugar
OH
Fat
H2 O
Fatty acid
Glycerol
H2 O
H
H O
OH
H
OH
H
H2 O
Cells use amino acids from the cheese and
other foods to produce new human proteins
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H
Enzyme
(amylase)
Enzyme (lipase)
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Swallowing
A Tour of the Human Digestive System
 Why doesn’t food go down the wind pipe?
 During swallowing:
 A reflex tips the …
 First stop: the mouth
 Functions in:
 Eating & chewing = …
 The initial steps of
digestion
NOT SWALLOWING
Tongue
 Salivary glands secrete
saliva
Pharynx
Trachea
(windpipe)
open
 Contains an enzyme that
begins starch digestion = …
SWALLOWING STARTED
Ball of
food
Epiglottis
up
Esophageal
sphincter
(contracted)
Esophagus
closed
SWALLOWING FINISHED
Epiglottis
down
Adam’s
apple
Trachea
closed
Epiglottis
up
EsophagusTrachea
open
open
Esophageal
sphincter
(contracted)
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Esophagus
The Stomach
 Muscular tube
 Connects mouth to
stomach
 Moves food by waves of
muscular contraction &
relaxation = …
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Esophageal sphincter
(contracted)
Food ball
Relaxed muscles
Contracted muscles
Relaxed muscles
Stomach
 Can store food for
several hours
 Churns food into a
thick soup called …
 Flow in / out of the
stomach controlled
by …
 Stomach lining
secretes gastric
juice
 Contains an
enzyme that
digests protein =
…
Esophagus
Control
of flow
Accordion-like
folds allow the
stomach to expand.
Food
particle
Stomach lining
Small intestine
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What Causes Gastric Ulcers?
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What Causes Heartburn?
 A bacterium that lives in
mucus & can cause
gastric ulcers = …
 It produces an enzyme
that shields the
bacterium from the
acidity of the stomach
 Backflow of chyme
into esophagus
 HCl irritates the
esophageal wall
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Small Intestine
Duodenum
 First part of the small
intestine
 Site of most digestion
 Chyme from the stomach
mixes with digestive juices
from …
 The longest part of the
alimentary canal
 The major organ for
digestion & absorption of
nutrients
 Juice that neutralizes
stomach acids in the
duodenum secreted by the …
 The liver secretes …, which:
 Is stored in the gallbladder
 Helps digest fats
 3 regions: …
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Absorption of Nutrients
Large Intestine
 In the duodenum, nutrients are:
Blood vessels
 Completely digested
 Ready to be absorbed
Muscle
layers
Intestinal wall
Villi
Interior of
intestine
Nutrient
absorption
 Main portion of the
large intestine = …
 Absorbs water
Colon of
large
intestine
 Produces feces
 The surface area and capacity for absorption
increased by …
 The rectum stores
feces
Small
intestine
Rectum
Anus
Figure
22.14a
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Nutrition – Overview
Mouth
Ingestion
Food into mouth
Digestion
Mechanical digestion
Chewing in mouth
Churning in stomach
Chemical digestion
Saliva in mouth
Acid & pepsin in
stomach
Enzymes in small
intestine
Absorption
Nutrients & water
in small intestine
Water in large
intestine
Elimination
Feces formed in
large intestine
Elimination from anus
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 What are nutrients?
 Why isn’t alcohol a nutrient?
 What are the main functions of nutrients in your
body?
 What are the 6 types of nutrients & their functions?
 What is a calorie?
 What is an essential nutrient?
 What are micronutrients?
Food
Stomach
Small
intestine
Large
intestine
Anus
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19
What is a Nutrient?
Six Types of Nutrients
 Any substance that the body uses to:
 Provide energy (calories)
 Regulate body processes
…
 Is alcohol a nutrient?
 Provides energy (7 Cal/g)
 No necessary function in the body
 Toxic in large amounts
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Nutrients
Water
 The body is about … %
water
 Some nutrients
supply …
 Found both inside & outside
the cells
 Functions include:
 Helps regulate body
temperature
 Transports nutrients
 Excretes waste
Protein
Carbohydrates
 Energy needed to
power muscle
contraction, maintain
body temp & other
cell functions
Fats
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Calories
 Calories measure
energy
 One calorie =
amount of energy
required to raise
the temperature of
…
Nutrient
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Some Nutrients Regulate Body Processes
Energy
 Vitamins & minerals (the
micronutrients) & water
Carbohydrate 4 cal/g
Protein
4 cal/g
Fat
9 cal/g
 Vision
 Metabolism
 Iodine is a component of …
 Iron helps transport O2
 Blood pressure
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Kinds of Fats
How Does the Body Use Carbs & Fats?
 Primary energy source for
the body = carbohydrates
 Provide undigestible complex
carbohydrates = …
Unsaturated Fatty Acids
(Some Double Bonds C=C)
 Dietary fats provide:
 Energy
 Fat-soluble vitamins
(vitamins A, D, E & K)
 Essential fatty acids (omega3 & omega-6)
 Long-term energy storage in
…
Reduce Heart
Disease Risk
Saturated Fatty Acids
(All Single Bonds C-C)
Heighten Heart
Disease Risk
Trans-Fatty Acids (Hydrogenated)
Heighten Heart
Disease Risk
Not Found Naturally!
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Cholesterol
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LDL & HDL Cholesterol
 Found in cell membranes
 HDL delivers cholesterol to
liver for elimination
 Protects against heart
disease
 Only found in animal
tissues (not in plants)
 LDL or “Lousy” cholesterol
 Transports cholesterol to
the cells
 Contributes to plaques
 High levels raise risk of
heart disease
 Used to make:
…
…
…
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Essential Amino Acids
Protein
 Builds & maintains tissues:
 Muscle, bone, skin & hair
 Regulates body functions
 Many hormones are proteins
 Protects from illness
 Antibodies are protein
 Must be obtained from
the diet – the body
can’t synthesize them
 Different foods contain
different essential
amino acids
 Used for energy
 Sources: …
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Micronutrients
Water-soluble Vitamins
 Essential (can’t be made by body)
 Required in small amounts
 Vitamins
 Fat-soluble: …
 Stored in body fat
 Toxic if consumed in excess
 Water-soluble: …
 Minerals
 Calcium, iron, iodine, zinc &
others
 Vitamin C, B-vitamins
 Need to be consumed regularly
 Not stored in the body to any
extent
 Excess excreted in urine
 Very diverse functions
 B vitamins are involved in …
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Good Nutrition
Minerals
 Getting the correct nutrients
 Foods that provide energy
 Essential nutrients that the
body can’t make
 Getting the …
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Basic Nutritional Advice
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Alcohol: the good, the bad & the ugly
 Eat a variety of foods
including: …
 People drink to relax,
celebrate & socialize
 Eat less
 Avoid too much junk food
 Exercise regularly
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 Harmful effects include:
…
…
…
…
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Effects of Alcohol
Alcoholic Liver Disease
 After just a few days
of overconsumption
=…
 Fibrosis
 Cirrhosis
 Permanent damage
 Scar tissue has
developed
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Which Are Used for Body Structure?
Which Nutrients Provide Energy?
Vitamins
Minerals
Carbohydrates
Vitamins
Minerals
Protein
Fats
Carbohydrates
Protein
Fats
Water
Water
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Homework
Which Regulate Body Functions?
 Record everything you eat or drink–and the
amount–for 24 hr (1 day)
 Analyze your diet using fitday.com
 Bring the fitday reports & a nutrition facts label
from your favorite snack food to lab next week
 Test your knowledge
Vitamins
Minerals
Carbohydrates
Fats
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 Answer questions 1, 5, 9, 11-15, 18, 19 at the end of
Ch 8
Protein
Water
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