Transcript digestive - ANATOMY AND PHYSIOLOGY

DIGESTIVE SYSTEM
Purpose for digestive system
To break down food into useable
nutrients that can be absorbed and
transported to cells throughout
body
Remember – we are heterotrophs!
NUTRITION
The Study of What we Eat
•What it does to the body
•What it does for the body…Biology,
Chemistry, and Physiology.
•WHY WE EAT WHAT WE EAT ?
•Personal Preferences
•Social
•Values and Beliefs
•Temptation
•Reward or Consolation
We need…
water, salts
Vitamins and minerals – to maintain
overall health
Macromolecules
– Carbs for energy
– Proteins for building and repairing of
tissues
– Lipids for stored energy source, brain
development (babies), essential for fatsoluble vitamins
ANATOMY- know pathway food
travels
PHYSIOLOGY of human digestive
tract
Two main parts
– Alimentary canal – the tube or pathway
that the food travels through
– Accessory glands – outside of the “tube”
but aid in digestion by secreting
enzymes into the tract
Accessory glands
Fill in the enzymes they secrete as
we go through the whole process
– Salivary gland –
– Pancreas –
– Liver –
– Gall bladder –
How does the Peanut Butter and Jelly
sandwich we eat for lunch become the
vitamins our body needs??
Must be broken down into simpler
substance and absorbed into the
bloodstream
Digestive System
Alimentary canal= a long winding
tube (with openings at
each end) made of
organs through which
food passes .
Mechanical digestion = breaking down,
mashing food
Chemical digestion = changing food
into simpler substances
using enzymes
DIGESTION
The Mouth
Salivary glands=Secretion of saliva
Contains amylase (enzymes) breaks
down carbohydrate chains.
Tongue assesses the amounts and
type of tastes found in saliva, and
pushes the food down
The Esophagus
Tube through which food is
transported with peristaltic motion
Pharynx
Pharynx – passageway for both air
into lungs and food into esophagus
epiglottis – blocks trachea when
swallowing so bolus (food ball)
enters the esophagus
Opening called the glottis is covered
by a flap called epiglottis. Which
prevents choking by covering the
trachea (breathing tube) when
swallowing.
The Stomach
Digests proteins using gastric juices.
Enzymes=gastrin and pepsin helps in
large proteins. The pH of stomach is
critical to the activation of pepsin.
Average capacity is one liter.
Food stay is stomach 2 to 3 hours.
Fatty meals or solid food takes longer
to digest then liquids or low fat
meals.
Absorbs only alcohol, water and a
little fat
Most of major nutrients are absorbed
in the small intestines.
The thick liquid/partially digested
food becomes chyme
Stomach
 gastric juice

pepsin

mucous
The Small Intestine
Duodenum The first part of the
small intestine where most chemical
digestion begins
Small intestine can be up to 10 ft. or
longer
Food may remain from 4 to 10 hrs.
Most digestion occurs here.
Villi increase surface area for
absorption
Small Intestines – the main player
Inside lining of Small Intestine
MAJOR SURFACE AREA FOR MAJOR ABSORPTION!
Asorption of nutrients in the small
intestine
capillaries receive –
carbohydrates and
proteins
•Nutrient rich blood
from S.I. is carried via
hepatic portal
vessel to the liver
•Liver is in charge of
distributing nutrients
to blood (and rest of
body
Asorption of nutrients in the small
intestine
Lacteals receive –
packaged lipids
•These lead to the
lymphatic system
which carries the
lipids to the heart
The Pancreas
Long soft gland lying behind the
stomach
Secretes enzymes into the
duodenum…trypsin,amylase,bicarbon
ate
Tiny intestinal glands are in lining of
small intestine.
The liver supplies duodenum with
bile.
Bile =A yellow-green juice acts like a dish
detergent and breaks fats into little
globules for fat digestion
Absorption of nutrients into the blood
occurs throughout the wall of the small
intestine
The intestine wall contains millions of tiny
finger-like projections called villi.
Each villus contains a network of blood
vessels (capillaries)
Blood carries these nutrients to liver
before it goes to rest of body.
Functions of The Liver
Changes surplus glucose to glycogen
for storage until glucose is needed.
Secrets bile
Stores fat
Breaks down and stores amino acids
used to form proteins.
Detoxifies alcohol and drugs
Stores vitamins A, D, E, K, and B12
Stores iron for use in red blood cells
The Large Intestine
The large intestine (colon)
Can be up to 6 ft. long
Holds food for as much as 3 days
Major function is to reabsorb the
water used during digestion and the
absorption of vitamins produced by
bacteria that live there and
elimination
Bacteria are permanent residents
Large Intestine
Bacteria aid in the digestion of plant
matter.
Bacteria produce vitamins B-12,
riboflavin, thiamine, and vitamin K
for absorption in the large intestine.
Water is removed from food.
Waste matter is packaged for
removal ( about ½ of it is dead
bacteria)
Biochemistry of Food
THE SIX BASIC NUTRIENTS
Nutrients That Provide Energy
Carbohydrates…simple & complex
Fats…saturated & unsaturated
Protein…build and repair
Nutrients That Regulate
Vitamins…fat & water soluble
Minerals…major & trace minerals
Water…most abundant nutrient
Energy = Calories
Food energy = Calories
1 Calorie=1kcal=1,000 calories
Biochemical Review
Protein
Carbohydrate
Lipid
Proteins
Proteins=CHONS
Amino acids are the smallest units
Complete proteins= contain all
essential amino acids, come from
animal products
Incomplete proteins=contain some
amino acids ex. Vegetables, grains,
beans, etc.
Carbohydrates
Sugars = CHO
simple= fructose, glucose,
lactose, sucrose
complex= starches, fibers
Simple sugars
Complex Carbs
Fats
Fats = Lipids
Lipids do not dissolve in water
Most concentrated form of
energy
Satisfied feeling
Saturated- solid @ room
temperature
Unsaturated- liquid @ room
temperature
Saturated vs Unsaturated Fats
Cholesterol
Found in foods that come from
animals
LDL= Good cholesterol
HDL= Bad cholesterol
Biochemistry of Food
THE SIX BASIC NUTRIENTS
Nutrients That Provide Energy
Carbohydrates…simple & complex
Fats…saturated & unsaturated
Protein…build and repair
Nutrients That Regulate
Vitamins…fat & water soluble
Minerals…major & trace minerals
Water…most abundant nutrient
Vitamins
Compounds found in living things
needed for life growth
Prevent disease
Found in foods
Look at chart on p. 214
Minerals
Simple substances found in the
environment, essential to the body’s
functioning
Ca, Mg, P, K, Na, Cl
Regulate the body’s processes:
building bones, clotting blood
Osteoporosis= lack of Ca, weak
and brittle bones
Hypertension= high blood
pressure, caused by too much Na
Energy = Calories
Food energy = Calories
1 Calorie=1kcal=1,000 calories
THE FOOD GUIDE PYRAMID
A Guide to Daily Food Choices
Guidelines for making food choices
by grouping foods and recommended
number of servings from each group
PRODUCT IDENTIFICATION
Food and Drug Administration
(FDA) Regulates the labeling of
foods.
The Name of Product -predominant
food first…..chicken and gravy
Style of The Product- sliced
peaches….whole kernel corn.
Name and Address of Manufacturer
Net Weight- weight of contents only
INGREDIENTS-descending order by
weight
NUTRITIONAL INFORMATIONcalories and the amount of nutrients
FOOD ADDITIVES- can be classified:
– Preservatives-prevent food from spoiling.
– ENRICHED-added to help replace those
nutrients that are lost
– FORTIFIED-those having vitamins and
minerals added.
– EMULSIFIERS-substances that make
food smooth.
– LEAVENING AGENT- substances such as
baking soda that makes bread and
cakes rise.
Over 2,800 additives have been
approved by the FDA in the U.S.
PRODUCT DATING- freshness, sell
and pull date, expiration.
SERVING SIZE- standard serving
size determined by FDA
NUTRITION LABELING- law
requires all processed foods that are
sources of nutrition. Calories,
percentage of daily requirements,
vitamins and minerals and
recommended amounts
HEALTH CLAIMS- can be made if
the product contains certain
nutrients that have proven to affect
health conditions
NATURAL=No Additives
ORGANIC=Grown without soil
chemicals or fertilizers.
HOMOGENIZED=Fat is dispersed
throughout into a smooth mixture.
PASTERUIZED=Partial sterilization of
a substance (as milk) at a
temperature for a period of exposure
that destroys objectionable
organisms without alteration of
substance.
METABOLISM
The means by which your body
releases the energy in food and uses
it to build and repair body tissue.
The factor that determines your
energy is BASAL METABOLISM the
amount energy needed by the body
when at rest and fasting to carry out
basic life functions such as breathing,
circulation and maintain body temp.
which may vary with age and size.
BMR..The rate at which the body
uses energy to support its basal
metabolism.
MALE…..little faster(larger mass)
FEMALE….slower
CALORIE…A measure of the energy
content of food. They are a measure
of heat energy released when
nutrients are burned or broken
down. The more calories a food has,
the more energy it contains.
Every gram of fat has 9 calories per
gram.
Every gram of Carbohydrates has 4
calories per gram.
Every gram of protein has 4 calories
per gram.
ADIPOSE TISSURE(FAT)…..Occurs
when someone takes in more
nutrients than he/she burns.
Healthy goal is….number of Kcal
consumed = Kcal required by body.
CALORIES IN…incoming calories from
food, the basic nutrients.
CALORIES OUT…to accurately
measure, estimate total energy used
by the body. 3 FACTORS:
1. BMR
2.Physical Activity
3.Digestion of Food
ENERGY EXPENDED FACTORS
1.
2.
3.
4.
5.
6.
Body Size & Composition
Sex
Age
Environment
Physiological State
Personal Life Style
Digestive enzymes
First place of chemical
digestion?
Second place for chemical
digestion?
Third place for chemical
digestion?
Role of temperature