Transcript Chapter 3 How Nutrients Become You

Chapter 3
How Nutrients Become You
Objectives
1.
Identify the six basic nutrient groups.
2.
Distinguish the functions of the major parts of the digestive
system.
3.
Describe the processes of absorption and metabolism.
4.
Explain factors affecting digestions and absorption.
5.
Name common digestive disorders.
Introduction
What does a car need to run?
•food is your body’s fuel
•when you eat, your body breaks down food and the
nutrients it contains into simpler elements
•energy is released and nutrients are used to help
build, repair and maintain body cell—then you body
discards the by-products of this process as waste
This chapter will help you picture the
process of how your body uses food from
beginning to end.
Six Groups of Nutrients Your
Body Needs
•carbohydrates
•vitamins
•fats
•minerals
•water
•proteins
Each nutrient has a specific job.
Each nutrient, in recommended quantities, is
vital to good health.
What happens when the body
does not get adequate amounts?
The Functions of Nutrients
•build and repair body tissues
•regulate all body processes
•provide energy
The Functions of Nutrients:
Build and Repair Body Tissue
•all cells are formed with materials that
come from food
•new cells account for your growth
•nutrient needs during rapid growth are
greater than any other time (prenatal period,
infancy, adolescence)
What is a result of lack of
nutrients during these periods?
The Functions of Nutrients:
Regulate Body Processes
•maintaining the correct acidbase is a function of nutrients
•digestion, absorption and
metabolism are also processes
that rely on proper amounts of
nutrients
The Functions of Nutrients:
Provide Energy
•food is to your body what gas is to a car
•food is a source of energy for performance
•the quality of food affects your performance
•energy is necessary for all life processes to
occur (breathe, move, pump blood, provide
heat)
•carbohydrates and fats are the two main
nutrients used for energy
The Energy Value of Food
calories: amount of heat needed to raise 1kg of water 1ºC
1gm Carbohydrates = 4 calories of
energy
1gm Fat = 9 calories of energy
1gm Protein = 4 calories of energy
1gm Alcohol = 7 calories of energy
Objective
1. Identify the six basic nutrient groups.
2. Distinguish the functions of the major
parts of the digestive system.
Review
What are the six
main nutrient
groups your body
needs?
What are the
two main
nutrients the
body uses for
energy?
What are the functions of
nutrients?
How many calories are in the following:
•1gm Carbohydrates
At what time are nutrient needs the greatest?
•1gm Protein
•1gm Fat
•1gm Alcohol
Activity
Individually Complete
Worksheet:
Determining Energy Values
(whole class period)
The Process of Digestion
Have you ever wondered what happens to a
piece of food after you put it in your mouth?
digestion: process by which your body breaks
down food, and the nutrients in food, into simpler
substances
*the blood then carries these simple substances to
cells for use in growth, repair and maintenance
Two Types of Digestion
1. mechanical (as food is chewed)
2. chemical (food mixed with acids
and enzymes)
enzymes: type of protein produced by cells that
cause specific chemical reactions
The GI Tract
As food is digested, it passes through a muscular tube
leading from the mouth to the anus. This is called the
GI tract.
Burgundy = mouth and esophagus (10”)
Brown = stomach (8”)
Green = small intestine (20’)
Orange = large intestine (3’6”)
The average length of the human digestive tract
The Process of Digestion:
Step 1 In the Mouth
•Begins with mastication (chewing)
•the teeth and tongue move food and crush
•prepares food for swallowing
•about 9000 taste buds in the mouth
•the taste and smell of food trigger salivary glands in
your mouth
The Process of Digestion:
Step 1 In the Mouth
•these glands produce saliva (99% water and
1% chemicals)
•one in particular is salivary amylase (breaks
down carbohydrates, starches, to simple
sugars)
•saliva moistens mouth, softens and dissolves
foods, helps cleanse the teeth and neutralize
mouth acids
The Process of Digestion:
Step 1 In the Mouth
Experiment
Chew 2 unsalted crackers for 2 minutes without swallowing
Compare how the crackers tasted at first
with how they tasted after 2 minutes.
The change in taste from starchy to sweet
was caused by the chemical action of the
enzyme salivary amylase—breaks down the
start in food to simple sugars
The Process of Digestion:
Step 2 In the Esophagus
•the esophagus is a tube about 10” long that connects the
mouth to the stomach
•there are 2 tubes in the throat, the other being the trachea
•when you swallow food, a flap of skin called the epiglottis
closes to keep food from entering the trachea
•breathing automatically stops when you swallow food to
prevent choking
•a series of squeezing actions by the muscles in the
esophagus, called peristalsis, helps food move through the
tube
The Process of Digestion:
Step 3 In the Stomach
•when you eat, the stomach produces gastric
juices to prepare for digesting the oncoming food
•gastric juices contain hydrochloric acid,
digestive enzymes and mucus
•the mixture of gastric juices and chewed and
swallowed food combine in the stomach—this
mixture is called chyme
The Process of Digestion:
Step 3 In the Stomach
•the acid in the stomach is as strong as car battery
acid, but a thick lining called mucosa protects the
stomach from its juices
•protein absorption begins in the stomach—the
gastric enzyme that breaks down protein is pepsin
•food stays in the stomach only 2-3 hours
•from the stomach, chyme moves to the small
intestine
The Process of Digestion:
Step 4 In the Small Intestine
•95% of digestion occurs here
•has 3 sections—duodenum, jejunum and ileum
•takes about 5-14 hours for food to travel from the
mouth through the small intestine
•peristalsis helps the food move through the small
intestine
Small intestine helpers:
•pancreas
•liver
The Process of Digestion:
Step 4 In the Small Intestine
Pancreas
•behind the stomach
•neutralizes hydrochloric acid that has come from the stomach
•produces enzymes that aid digestion in the small intestine (breaks down fats,
carbohydrates and proteins)
Basic Part
proteins
amino acids
Enzyme That
Does the Work
proteases
carbohydrates
monosaccharides
saccharidases
fats
fatty acids, glycerol, lipases
monoglycerides
The Process of Digestion:
Step 4 In the Small Intestine
Liver
•located above the stomach
•produces bile, which aids fat digestion
•bile helps disperse fat in the water-based
digestive fluids
•bile is store in the gall bladder
The Process of Digestion:
Step 5 In the Large Intestine
•aka the colon
•very little digestion occurs here
•main job is to reabsorb water
•chyme stays in the colon 1-3 days before elimination
•solid wastes that result from digestion are called feces
•the end of the large intestine is called the rectum—the
feces collect here until they are ready to pass from the
body through the anus
Objectives
1. Describe the processes of absorption and
metabolism.
2. Explain factors affecting digestion and absorption.
Review
Complete Worksheet:
Food Breakdown
(5-10 minutes)
and
Complete Worksheet:
Nutrient Digestion in the Small Intestine
(5-10 minutes)
Activity
Complete in the Lab
The Digestion Experiment
I will assign your lab partners!
Objectives
1. Describe the processes of absorption and
metabolism.
2. Explain factors affecting digestion and absorption.
Absorption of Nutrients
After being digested in the small intestine,
nutrient in food are ready for absorption.
absorption: passage of nutrients from the digestive tract into
the circulatory or lymphatic system
Absorption of Nutrients
The inside surface area of the small intestine is about 600 times
larger than that of a small tube.
how?
The wall of the small intestine is pleated with 1000’s of folds
that are covered with villi.
villi: tiny, fingerlike projections that give the lining of the small intestine
a velvetlike texture
every cell of the villus is covered with microvilli, which
are microscopic hairs that help catch nutrient
particles
Absorption of Nutrients:
Water-Soluble Nutrients
•dissolve in water
•include amino acids, monosaccharides, minerals,
most vitamins and water
•tiny blood vessels in the villi, called capillaries,
absorb water-soluble nutrient into the bloodstream
•carried to the liver
Absorption of Nutrients:
Fat-Soluble Nutrients
•dissolve in fat
•include a few vitamins, fatty acids, glycerol and
monoglycerides
•lymph vessels in the villi, called lacteals, absorb
fat-soluble nutrients into the lymphatic system
•carried to the bloodstream
The large intestine finished the job of
absorption.
Metabolism
•once the nutrients are digested and absorbed, the
circulatory system takes over
•the circulatory system carries nutrient and oxygen to
cells
metabolism: all the chemical changes that occur as cells
produce energy and materials needed to sustain life
Metabolism
Through metabolism, cells breakdown some nutrients to
release energy, called ATP
ATP: storage form of energy in the body
**when the body needs energy, chemical reactions break
down ATP to release energy**
Factors that Affect Digestion and
Absorption
Have you ever been nervous or worried and felt
food in your stomach like a rock?
•eating habits
•emotions
•food allergies
•physical activity
Healthy lifestyle choices can help you avoid
many GI problems.
Factors that Affect Digestion and Absorption:
Eating Habits
•too little food can cause a lack of nutrients, which
can affect how your body will digest and absorb
other nutrients
•eat plenty of fruits and vegetables and whole grain
products—they are high in fiber
•eating too much food too fast places stress on
mechanical and chemical reactions needed for
digestion
Factors Affecting Digestion and Absorption:
Emotions
•emotions like fear, anger and tension can
cause digestive disorders
•make a point to reduce stress and tension
while eating
HOW?
Factors Affecting Digestion and Absorption:
Food Allergies
•the immune system is the body’s defense system
•made up of the tonsils, thyroid, lymph glands, spleen and white
blood cells
•protects the body against disease and foreign materials with proteins
called antibodies
food allergy: a reaction of the immune system to some
substance found in food
•vomiting
•stomach pain
•intestinal distress
•skin rashes
•swelling
•breathing problems
Factors Affecting Digestion and Absorption:
Physical Exercise
•exercise can aid digestion and
metabolism
•stimulates a healthy appetite and
strengthens the muscles of internal
organs
•it helps move food through the GI tract
•helps reduce stress
Digestive Disorders
Use worksheet for note taking.
Digestive Disorders: Diarrhea
diarrhea: frequent expulsion of watery feces
•diarrhea causes food to move through the digestive system
too quick for nutrients to be fully absorbed
Cause
•food sensitivity, harmful bacteria or stress
Cure
•water to restore fluid loss, medications
Digestive Disorders: Constipation
constipation: occurs when chyme moves very slowly
through the large intestine (too much water is reabsorbed
from chyme)
•causes the feces to become hard, making BM’s painful—hemorrhoids
Cause
•erratic eating habits, low fiber intake, lack of physical
activity, not drinking enough water
Cure
•laxatives, high fiber diet, exercise, drink plenty of
water
Digestive Disorders: Indigestion
indigestion: difficulty in digesting food
*symptoms include gas, stomach cramps and nausea
Cause
•stress, eating too much or too fast, eating certain foods
Cure
•antacids (neutralize stomach acids), modify diet, eat in
a relaxed atmosphere
Digestive Disorders: Heartburn
heartburn: burning pain in the middle of the chest
**has nothing to do with the heart
Cause
•stomach acid flowing back into the esophagus (aka
reflux)
Cure
•antacids
Digestive Disorders: Ulcer
ulcer: open sore in the lining of the stomach or small intestine
Cause
•bacterium, heredity, stress, excessive alcohol use
**ulcerated area becomes inflamed and person experiences a
burning pain
Cure
•antibiotic therapy, eat nutritious diet, decrease stress,
physical exercise
Digestive Disorders: Gallstones
gallstones: small crystals that form from bile in the
gallbladder
Cause
•when bile forms solid particles (stones) in the
gallbladder
Cure
•diets low in fat, removal of gall bladder
Digestive Disorders: Diverticulosis
diverticulosis: a disorder in which many abnormal pouches
form in the intestinal wall
Cause
•occurs when intestinal muscles become weak (when
the diet is too low in fiber), high-fat diet and an inactive
lifestyle
Cure
•high-fiber diet which will help keep the intestinal
muscles toned