DIGESTIVE SYSTEM

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DIGESTIVE SYSTEM
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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!

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NUTRITIONThe Study of What we Eat

• What it does to the body
• What it does for the bodyBiology, Chemistry, and
  Physiology.
• WHY WE EAT WHAT WE EAT ?
• Personal Preferences
• Social
• Values and Beliefs
• Temptation
• Reward or Consolation

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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 fat-soluble
  vitamins

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ANATOMY- know pathway food travels
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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

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Accessory glands

• Fill in the enzymes they secrete as we go through
  the whole process
• Salivary gland
• Pancreas
• Liver
• Gall bladder

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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

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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

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DIGESTION

• The Mouth
• Salivary glandsSecretion 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

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Pharynx

• Pharynx passageway for both air into lungs and
  food into esophagus
• epiglottis blocks trachea when swallowing so
  bolus (food ball) enters the esophagus

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• 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.
• Enzymesgastrin and pepsin helps in large
  proteins. The pH of stomach is critical to the
  activation of pepsin.

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• 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

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Stomach

• gastric juice
• pepsin
• mucous

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• 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

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Small Intestines the main player
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Inside lining of Small Intestine
MAJOR SURFACE AREA FOR MAJOR ABSORPTION!
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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

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Asorption of nutrients in the small intestine

• Lacteals receive packaged lipids
• These lead to the lymphatic system which carries
  the lipids to the heart

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The Pancreas

• Long soft gland lying behind the stomach
• Secretes enzymes into the duodenumtrypsin,amylase
  ,bicarbonate
• Tiny intestinal glands are in lining of small
  intestine.
• The liver supplies duodenum with bile.

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• 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.

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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

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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

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Large Intestine
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• 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)

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Biochemistry of Food
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THE SIX BASIC NUTRIENTS

• Nutrients That Provide Energy
• Carbohydratessimple complex
• Fatssaturated unsaturated
• Proteinbuild and repair
• Nutrients That Regulate
• Vitaminsfat water soluble
• Mineralsmajor trace minerals
• Watermost abundant nutrient

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Energy Calories

• Food energy Calories
• 1 Calorie1kcal1,000 calories

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Biochemical Review

• Protein
• Carbohydrate
• Lipid

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Proteins

• ProteinsCHONS
• Amino acids are the smallest units
• Complete proteins contain all essential amino
  acids, come from animal products
• Incomplete proteinscontain some amino acids ex.
  Vegetables, grains, beans, etc.

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Carbohydrates

• Sugars CHO
• simple fructose, glucose, lactose, sucrose
• complex starches, fibers

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Simple sugars
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Complex Carbs
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Fats

• Fats Lipids
• Lipids do not dissolve in water
• Most concentrated form of energy
• Satisfied feeling
• Saturated- solid _at_ room temperature
• Unsaturated- liquid _at_ room temperature

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Saturated vs Unsaturated Fats
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Cholesterol

• Found in foods that come from animals
• LDL Good cholesterol
• HDL Bad cholesterol

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Biochemistry of Food
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THE SIX BASIC NUTRIENTS

• Nutrients That Provide Energy
• Carbohydratessimple complex
• Fatssaturated unsaturated
• Proteinbuild and repair
• Nutrients That Regulate
• Vitaminsfat water soluble
• Mineralsmajor trace minerals
• Watermost abundant nutrient

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Vitamins

• Compounds found in living things needed for life
  growth
• Prevent disease
• Found in foods
• Look at chart on p. 214

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Minerals

• Simple substances found in the environment,
  essential to the bodys functioning
• Ca, Mg, P, K, Na, Cl
• Regulate the bodys processes building bones,
  clotting blood
• Osteoporosis lack of Ca, weak and brittle bones
• Hypertension high blood pressure, caused by too
  much Na

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Energy Calories

• Food energy Calories
• 1 Calorie1kcal1,000 calories

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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

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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

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• INGREDIENTS-descending order by weight
• NUTRITIONAL INFORMATION-calories 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

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• 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.

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• 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

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• NATURALNo Additives
• ORGANICGrown without soil chemicals or
  fertilizers.
• HOMOGENIZEDFat is dispersed throughout into a
  smooth mixture.
• PASTERUIZEDPartial sterilization of a substance
  (as milk) at a temperature for a period of
  exposure that destroys objectionable organisms
  without alteration of substance.

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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.

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• BMR..The rate at which the body uses energy to
  support its basal metabolism.
• MALE..little faster(larger mass)
• FEMALE.slower
• CALORIEA 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.

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• 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.

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• CALORIES INincoming calories from food, the
  basic nutrients.
• CALORIES OUTto accurately measure, estimate
  total energy used by the body. 3 FACTORS
• 1. BMR
• 2.Physical Activity
• 3.Digestion of Food

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ENERGY EXPENDED FACTORS

• 1. Body Size Composition
• 2. Sex
• 3. Age
• 4. Environment
• 5. Physiological State
• 6. Personal Life Style

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Digestive enzymes
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First place of chemical digestion?
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Second place for chemical digestion?
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Third place for chemical digestion?
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Role of temperature