Chapter 30, 10.4 & 30.1
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Transcript Chapter 30, 10.4 & 30.1
Digestion and
Nutrition
Chapter 30 (M)
Food and Nutrients
Food Any substance, either raw or
processed which is meant for human
consumption
Nutrients The components of food
that the body can use for growth,
repair and energy
How Nutrients are Obtained
Heterotrophs get
nutrients in various
ways
Types of Nutrients
Carbohydrates
Proteins
Fats
Vitamins
Minerals
Water
Food as Fuel
Carbohydrates, fats and proteins are all
used to generate ATP
Fats9 Calories/gm, Proteins and
Carbs 4Calories/gm
1 Calorie (kilocalorie)= 1000 calories
Basic Calorie need 2200 for female
teens, 2500 males
Essential nutrients
Must
these
be ingested, cell can’t construct
Essential
Fatty Acids Linoleic Acid
Essential Amino Acids 8 AA
Vitamins water soluble (can be
excreted) and fat soluble( excess might
cause damages), reqd for enzyme function
Minerals reqd, but large amts can cause
damage
Nutrition and a Balanced Diet
Balanced Diet provides nutrients in
adequate amounts and enough energy to
maintain a healthful weight
Balancing your diet
Food
labels
Food guide pyramid
The Food Guide Pyramid
The Food Guide Pyramid
Number of calories depends on:
Age
Sex
Size
Whether or not you are a pregnant or breastfeeding woman
Whether you have a chronic illness
The National Academy of Sciences recommends the following
calorie categories:
1,600 calories - Many sedentary women and some older adults
2,200 calories - Children, teenage girls, active women and many
sedentary men.
Women who are pregnant may need around 500 calories more per
day and an additional 300 calories for breast-feeding
2,800 calories - Teenage boys, active men and very active women
The Food Guide Pyramid can be extremely useful - whether you
want to gain weight, lose weight or maintain your weight. Eating
a healthy diet is a little easier if you base your choices on the
Food Pyramid.
MyPyramid USDA's newest
food pyramid guide
Encourages consumers to make healthier
food choices
To get regular exercise
Food groups are arranged in vertically bands,
instead of horizontal ones
Band width indicates portion size
The wider the band, the more food from
that group should be eaten.
The Digestive System
Converts food into small molecules that
can be used by all cells of the body
Food is processed in four phases by the
digestive system
Stages of Food Processing
Ingestion: eating or drinking
Digestion : Breaking food into smaller
molecules
1.
2.
•
•
3.
4.
Mechanical
Chemical (Enzymes)
Absorption: nutrient molecules enter
blood, the circulatory system
transports it through out the body
Elimination: undigested material passes
out of the body
The Digestive System
Functions
like a series of tube like
organs which pass through the body
from the mouth to the anus
Alimentary Canal
Alimentary Canal can be about 30’
long
Accessory organs Pancreas, Liver,
Gallbladder secrete enzymes that
are released into the food tube
Digestion in the Mouth
It all begins in the mouth . . .
Teeth,
tongue
Salivary glands
Mucus
Amylase
Only carbohydrates are digested
here
SWALLOWING AND PERISTALSIS
GLOTTIS AND EPIGLOTTIS
Peristalsis
Rhythmic muscular contractions propel a
bolus of food
The human digestive system
Digestion in the Stomach
Muscular organ
Acts as a
reservoir where
food is prepared
for digestion in
the SI
Produces Gastric
Juices
Stomach Functions
Food Storage
2. Mechanical Digestion
3. Chemical Digestion
Secretions:
1. Mucus
2. EnzymePepsinogen
3. HCL
1.
CHYME semi-fluid food
mixture leaves.
Protection from Self-Digestion
Protective
lining
Main enzyme -Pepsin is
inactive Pepsinogen when
secreted
Digestion in the Stomach
Pepsinogen Comes in contact with HCl
Pepsin
Pepsin converts proteins into peptones
Acidity of Gastric juices kills some
bacteria that enters with food
Gastric Juices stimulated by
psychological and chemical means
Peristaltic process of moving chyme into
the SI takes place for 6hrs
Small Intestine
Digestion in the Small Intestine
Main stage of Digestion
As chyme enters the SI secretes juices that are
alkaline and neutralizes the acidity
SI maltase,lactase,sucrase breaks
disaccharides
Liver secretes bile emulsifies fats
Dipeptidases dipeptides into AAs
Pancreas
Trypsin & Chymotrypsin break down proteins
Amylase converts starch into maltose
Lipase breaks fats
Process is complete in about 4 hrs
Pancreas
Secretes
Hormones
Sodium bicarbonate
Digestive enzymes
Lipase
Trypsinogen
Amylase
Liver
Secretes
Blood clotting
enzymes
Stores glycogen
Bile
Stored in gall
bladder
Emulsifies fat
The structure of the Small
Intestine
LARGE INTESTINE = COLON
1.
Anatomy:
2. Functions
a. Reclaim water
b. Synthesis of vitamins by E. coli
Feces
Rectum
Anus
Diarrhea
Constipation
Can you name the parts and tell what
they do?