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The Remarkable Body
Chapter 3
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Learning Objectives
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Describe the levels of organization in the
body, and identify some basic ways in
which nutrition supports them.
Describe the relationship between the
body’s fluids and the cardiovascular
system and their important to the
nourishment and maintenance of body
tissues.
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Learning Objectives
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Summarize the interactions between the
nervous and hormonal systems and
nutrition.
State how nutrition and immunity are
interrelated, and describe the importance
of inflammation to the body’s health.
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Learning Objectives
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Compare the terms mechanical digestion
and chemical digestion, and point out
where these processes occur along the
digestive tract with regard to
carbohydrate, fat, and protein.
Name some common digestive problems
and off suggestions for dietary alterations
that may improve them.
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Learning Objectives
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Identify the excretory functions o the
lungs, liver, kidneys, and bladder, and
state why they are important to maintain
normal body functioning.
Identify glycogen and fat as the two forms
of nutrients stored in the body, and
identify the liver, muscles, and adipose
tissue as the body tissues that store them.
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Learning Objectives

Define the term moderate alcohol
consumption, and discuss the potential
health effects, both negative and positive,
associated with this level of drinking.
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body’s Cells
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Body is composed of trillions of cells
Body needs nutrients
Cells are self-contained, living entities
Depend on one another
 Basic needs
 Essential nutrients
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Cells die at varying rates
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
A Cell (Simplified Diagram)
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body’s Cells
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Genes Control Functions
Direct production of proteins
 Provide instruction for structural
components of cells
 Affects how body handles nutrients
 Complete set of genes in each cell
 Gene variations
 Inborn error of metabolism
 Influence of nutrients
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
From DNA to Living Cells
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body’s Cells
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Cells, tissues, organs, systems
Cells into tissues
 Tissues into organs
 Organs together as part of body systems
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body Fluids and the
Cardiovascular System
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Body fluids
Supply energy, oxygen, nutrients, and
water
 Deliver fresh supplies and pick up wastes
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Circulating fluids
Blood
 Arteries, veins, capillaries
 Plasma
 Lymph
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Blood Flow in the Cardiovascular
System
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body Fluids and the
Cardiovascular System
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Plasma
Extracellular fluid
Intracellular fluid
All cell reactions
take place
 Holds cellular
shape
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body Fluids and the
Cardiovascular System
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All blood circulates
to the lungs
Picks up oxygen
 Releases
carbon
dioxide
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body Fluids and the
Cardiovascular System
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Blood returns to heart
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Blood pumped to rest of body
 Delivers nutrients & picks up wastes
Blood passes through digestive system
Picks up nutrients
 Except for fats
 Fats travel via lymph
 Routed directly to liver
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Lymph Vessels and the
Bloodstream
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Body Fluids and the
Cardiovascular System
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Kidneys
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Cleansing of
wastes
Fluid intake
Red blood cell life
expectancy
Blood is sensitive
to malnutrition
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Hormonal and Nervous
Systems
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Hormones
Chemical messengers
 Secreted and released directly into blood
by glands
 Stimulate organs to take action
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Glands monitor conditions in the body
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Pancreas
 Insulin and glucagon
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Hormonal and Nervous
Systems
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Nutrition affects the hormonal system
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Hormones affect nutrition
 Examples
Nervous system
Receives and integrates information from
sensory receptors
 Role in hunger regulation
 Cortex and hypothalamus
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Cutaway Side View of the Brain
Showing the Hypothalamus & Cortex
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Hormonal and Nervous
Systems
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Fight-or-flight reaction (stress response)
Neurotransmitters
 Epinephrine and norepinephrine
 Metabolism speeds up
 Organ response
 Eyes, heart, liver, stomach
 Heart disease
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Immune System
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Cooperation among tissues to maintain
defenses
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Physical barriers
Antigen
Immune defenses
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White blood cells
 Phagocytes
 Lymphocytes (T-cells and B-cells)
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Immune System
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Inflammation
Response to injury or irritation
 Increased white blood cells, redness,
heat, pain, swelling
 Normal and healthy response
 Problem with chronic inflammation
 Dietary factors
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Digestive System
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Five basic chemical tastes
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Sweet, sour, bitter, salty, and umami
Other factors affecting experience of food
flavor
Sweet, salty, and fatty foods
Almost universally desired
 Can lead to drastic overeating of these
substances
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Innate Preference for Sweet
Taste
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Digestive System
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Digestive tract
Flexible, muscular tube
 Path
 Total length of about 26 feet
 Body surrounds digestive canal
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System’s job is to digest food to its
components, absorb, and excrete
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System works at two levels
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Digestive
System
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Digestive System
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Mechanical digestion
Begins in the mouth
 Chewing
 Stomach and small intestine
 Peristalsis
 Chyme travels through pyloric valve
 Large intestine
 Digestion is virtually continuous
 Sleep and exercise
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Peristaltic Wave Passing Down
the Esophagus and Beyond
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Muscular Stomach
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Digestive System
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Chemical digestion
Digestive juices
 Salivary glands, stomach, pancreas, liver,
and small intestine
 Mouth
 Saliva – starches and fat
 Saliva – health of teeth
 Stomach
 Hydrochloric acid – protein
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
pH Values of Digestive Juice and
Other Common Fluids
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Digestive System
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Chemical digestion
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Intestine
 Bile
 Pancreatic juice
 Digestive enzymes in wall of intestine
 Fiber
Food combinations and digestion
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
“I Am What I Eat”
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Within 24 to 48 hours
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90% of carbs, fat, and protein are digested
and absorbed
Mouth
Food is crushed, mashed, and mixed with
saliva
 Carbohydrate digestion begins
 Swallowing
 Peristalic waves
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
“I Am What I Eat”
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Stomach
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Gastric juice mixes with food
 Unwinds proteins
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Chyme
Small intestine
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Bile from the liver
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Pancreas
Large intestine
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Typical Digestive System Transit
Times
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
“I Am What I Eat”
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Absorption
Nutrient molecules transverse intestinal
lining
 Water-soluble components
 Fat-soluble components
 Cells of small intestine are selective
 Folded structure
 Villi
 Microvilli
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Details of the
Small
Intestine
Lining
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
“I Am What I Eat”
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Transport
Lymph vessels
 Products of fat digestion
 Fat-soluble vitamins
 Blood vessels
 Products of carbohydrate & protein
digestion
 Most vitamins
 Minerals
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Nourishment of digestive tract
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
A Letter from Your Digestive
Tract
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Hiccups
Fiber and gas
Heartburn
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Antacids
GERD
Ulcers
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
A Letter from Your Digestive
Tract
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Choking
Constipation & diarrhea
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Hemorrhoids
Irritable bowel syndrome (IBS)
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Normal Swallowing and Choking
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
First Aid for Choking
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Excretory System
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Organs involved in waste removal
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Lungs, liver, kidneys
Kidneys
Waste materials are dissolved in water
 Working units – nephrons
 Urine is stored in bladder
 Sodium and blood pressure
 Work regulated by hormones
 Importance of water supply
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Storage Systems
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Eating intervals of 4-6 hours
Major storage sites
Liver – carbohydrates
 Glycogen
 Muscles – carbohydrates
 Glycogen
 Fat cells – fat and fat-related substances
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Variations in nutrient stores
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol and Nutrition: Do the
Benefits Outweigh the Risks?
Controversy 3
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
U.S. Alcohol Consumption
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Total daily energy intake as alcohol
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U.S. average of 6 to 10 percent
Drinking pattern
Binge drinking
 Heavy drinking
 Moderate drinking
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Does Moderate Alcohol Use
Benefit Health?
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Influence of age
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Influence of drinking patterns
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Middle-aged people
Light to moderate intakes
Health benefits of wine
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Science is mixed
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
What is Alcohol?
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Names end in –ol
Act as lipid solvents
Ethanol
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Alcoholic beverages
Social interactions
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Nonalcoholic beverages
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
What is a “Drink”?
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Beverage volume
Proof
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Percentage of
alcohol
Defining a drink
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Drinking Patterns
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Defining moderation
Difficulties with defining
 Health authority definition
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Problem drinkers and alcoholism
Irrational and dangerous behaviors
 Health effects
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Heavy episodic drinking
Defined
 Harms
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Behaviors Typical of Moderate
Drinkers and Problem Drinkers
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Immediate Effects of Alcohol
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The body gives special attention to
alcohol
Diffusion through stomach walls
Reach brain within a minute
 Vomiting
 Presence of food in the stomach
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Absorption in small intestine
Alcohol dehydrates tissues
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Increased urine output
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol Arrives in the Brain
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Nerves
Inhibitory
 Excitatory
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Lethal dose
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Speed and amount consumed
Toxicity, oxidative stress, and the brain
Brain tissue shrinks
 Brain inflammation
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Accidents
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Effects of Rising Blood Alcohol
Levels on the Brain
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol Doses and Average
Blood Level Percentages
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Blood Alcohol and Traffic
Accidents
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol Arrives in the Body
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Liver processes most of the body’s
alcohol
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Alcohol breakdown in the stomach
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Alcohol dehydrogenase (ADH)
 Acetaldehyde
Women vs. men
Excretion in breath and urine
Rate of alcohol clearance
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol Breakdown
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol Affects the Liver
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Alcohol metabolism generates damaging
free radicals
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Diseases and organ damage
Fatty liver
Liver fibrosis
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Cirrhosis
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
The Hangover
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Mild form of drug withdrawal
Contributors to hangovers
Congeners
 Dehydration
 Formaldehyde
 Methanol
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Sure cure for hangover
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol’s Long-Term Effects
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Effects in pregnancy
Effects on heart and brain
Cancer
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Even moderate consumption increases
risk
Long-term effects of alcohol abuse
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Alcohol’s Effects on Nutrition
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Causes disturbances in nutrition
All discretionary calories
Fattening power of alcohol
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“Beer belly”
Effects on vitamins
Malnutrition
 Wernicke-Korsakoff syndrome
 Folate
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Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney
Calories in Alcoholic Beverages
and Mixers
Nutrition: Concepts & Controversies, 13th edition, Sizer & Whitney