Digestive Systems and Nutrition Chapter 36. Digestive Systems and Nutrition 2Outline Digestive Tracts Incomplete versus Complete Tracts Continuous

Digestive Systems and Nutrition

Chapter 36

2Digestive SystDigestive Systems and Nutritems and Nutritionion

OutlineOutlineDigestive TractsDigestive Tracts

Incomplete versus Complete TractsIncomplete versus Complete TractsContinuous versus Discontinuous Continuous versus Discontinuous FeedersFeeders

Dentition Among MammalsDentition Among MammalsHuman Digestive TractHuman Digestive Tract

MouthMouthStomachStomachSmall IntestineSmall IntestineAccessory OrgansAccessory OrgansLarge IntestineLarge Intestine

Digestive EnzymesDigestive EnzymesNutritionNutrition


Digestive TractsDigestive TractsIncomplete versus Complete TractsIncomplete versus Complete Tracts

Incomplete tract has a single openingIncomplete tract has a single openingEx: PlanarianEx: Planarian Food enters through mouth and muscular Food enters through mouth and muscular pharynxpharynxWastes exit through mouth and muscular Wastes exit through mouth and muscular pharynxpharynx Lacks specialized partsLacks specialized parts

Complete Tract has two openingsComplete Tract has two openingsEx: EarthwormEx: Earthworm Food enters through mouthFood enters through mouthWastes exit through anusWastes exit through anus

4Incomplete Digestive Tract of a Planarian

5 Complete Digestive Tract of an Earthworm


Continuous versus Discontinuous Continuous versus Discontinuous FeedersFeeders

Continuous filter feedersContinuous filter feedersEx: ClamsEx: ClamsAlways have water moving into the Always have water moving into the mantle cavity via incurrent siphonmantle cavity via incurrent siphonParticles deposited on gillsParticles deposited on gills

Do not need food storage areaDo not need food storage areaDiscontinuous feedersDiscontinuous feeders

Ex: SquidEx: SquidUses tentacles to seize preyUses tentacles to seize preyAllows the beaklike jaws to pull pieces Allows the beaklike jaws to pull pieces into the mouth with the radulainto the mouth with the radula

Food storage area neededFood storage area needed

7 Nutritional Mode of a Clam Compared to a Squid


Adaptations to DietAdaptations to Diet

Dentition differs with mode of nutritionDentition differs with mode of nutritionOmnivoresOmnivoresVariety of specializationsVariety of specializations

Accommodate both vegetation and meatAccommodate both vegetation and meatHerbivoresHerbivores Incisors for clippingIncisors for clipping

Premolars and molars for grindingPremolars and molars for grindingCarnivoresCarnivoresPointed incisors and enlarged caninesPointed incisors and enlarged canines

Shear off pieces small enough to swallow Shear off pieces small enough to swallow

9 Dentition Among Mammals


Human Digestive TractHuman Digestive Tract

Humans digestive tract is complete Humans digestive tract is complete

Part of a tube-within-a-tube body planPart of a tube-within-a-tube body plan

Begins with a mouth and ends in an Begins with a mouth and ends in an anusanus

Digestion entirely extracellularDigestion entirely extracellular

Digestive enzymes are secreted byDigestive enzymes are secreted by

The wall of the digestive tract, orThe wall of the digestive tract, or

By nearby glandsBy nearby glands

11The Human Digestive Tract


Human Digestive TractHuman Digestive Tract

MouthMouth

Three major pairs of salivary glandsThree major pairs of salivary glands

Saliva contains salivary amylaseSaliva contains salivary amylase

Salivary amylase initiates starch Salivary amylase initiates starch digestiondigestion

Tongue is composed of striated muscleTongue is composed of striated muscle

Mixes chewed food with salivaMixes chewed food with saliva

Forms mixture into bolusForms mixture into bolus


Pharynx and EsophagusPharynx and Esophagus

PharynxPharynxWhere digestive and respiratory Where digestive and respiratory passages come together passages come together

Soft palate closes off nasopharynxSoft palate closes off nasopharynxEpiglottisEpiglottisCovers opening into tracheaCovers opening into tracheaKeeps food from air passages (most of Keeps food from air passages (most of the time)the time)

EsophagusEsophagusTakes food to stomach by peristalsis Takes food to stomach by peristalsis Peristalsis - Rhythmical contraction to Peristalsis - Rhythmical contraction to move contents in tubular organsmove contents in tubular organs

14Swallowing

15Peristalsis in the Digestive Tract


StomachStomach

StomachStomach

Stomach wall has deep foldsStomach wall has deep folds

Folds disappear as the stomach fills to Folds disappear as the stomach fills to an approximate volume of one literan approximate volume of one liter

Epithelial lining of the stomach has Epithelial lining of the stomach has millions of gastric pits, which drain millions of gastric pits, which drain gastric glandsgastric glands

Pepsin is a hydrolytic enzyme that acts Pepsin is a hydrolytic enzyme that acts on protein to produce peptideson protein to produce peptides

17Anatomy of the Stomach


StomachStomach

Food mixing with gastric juices Food mixing with gastric juices becomes chymebecomes chyme

Junction between stomach and small Junction between stomach and small intestine controlled by a sphincterintestine controlled by a sphincter

When the sphincter relaxes, a small When the sphincter relaxes, a small quantity of chyme passes into the quantity of chyme passes into the small intestinesmall intestine


Small IntestineSmall IntestineFirst segment is duodenumFirst segment is duodenum

Chyme from stomach enters the Chyme from stomach enters the duodenumduodenum

Mixes with secretions from the liver and Mixes with secretions from the liver and pancreaspancreas

LiverLiver

Produces bile, which is stored in gallbladderProduces bile, which is stored in gallbladder

Bile contains bile salts which break up fat Bile contains bile salts which break up fat into fat droplets via emulsificationinto fat droplets via emulsification

Helps maintain glucose concentration in Helps maintain glucose concentration in blood by converting excess into glycogenblood by converting excess into glycogen

20Anatomy of the Small Intestine

21Liver, Gallbladder, and Pancreas


Small IntestineSmall IntestinePancreasPancreas

Exocrine glandExocrine gland

Produces pancreatic juice and digestive Produces pancreatic juice and digestive enzymes into the duodenumenzymes into the duodenum Pancreatic amylase digests starch to maltosePancreatic amylase digests starch to maltose

Trypsin digests protein to peptidesTrypsin digests protein to peptides

Lipase digests fat droplets to glycerol and Lipase digests fat droplets to glycerol and fatty acidsfatty acids

Epithelial cells intestine also produce Epithelial cells intestine also produce enzymesenzymes

These complete digestion of peptides and These complete digestion of peptides and sugarssugars

23Liver, Gallbladder, and Pancreas


Absorption by VilliAbsorption by Villi

Mucous membrane of small intestineMucous membrane of small intestine

Has ridges and furrows that give it a Has ridges and furrows that give it a corrugated surfacecorrugated surface

Villi are ridges on the surface, which Villi are ridges on the surface, which contain even smaller ridges, microvillicontain even smaller ridges, microvilli

Greatly increase absorptive areaGreatly increase absorptive area

Each villus contains blood capillaries Each villus contains blood capillaries and a lymphatic capillary (lacteal)and a lymphatic capillary (lacteal)

25Digestion and Absorption of Nutrients


Large IntestineLarge Intestine

Includes cecum, colon, rectum, and Includes cecum, colon, rectum, and anal canalanal canal

Larger in diameter, but shorter in Larger in diameter, but shorter in length than small intestinelength than small intestine

Absorbs water, salts, and some vitaminsAbsorbs water, salts, and some vitamins

Cecum has small projection - appendixCecum has small projection - appendix

Colon subdivided into ascending, Colon subdivided into ascending, transverse, descending, and sigmoid transverse, descending, and sigmoid coloncolon

Opening to anal canal - AnusOpening to anal canal - Anus

27Food Guide Pyramid


Nutrition:Nutrition:ProteinsProteins

Adequate protein formation requires 20 Adequate protein formation requires 20 different types of amino acidsdifferent types of amino acids

Adults require 8 from the diet, children Adults require 8 from the diet, children require 9require 9

Essential amino acidsEssential amino acids

Some foods, such as meat, milk, and eggs, Some foods, such as meat, milk, and eggs, provide all 20 (complete)provide all 20 (complete)

Vegetables supply one or more essential Vegetables supply one or more essential amino acids, but are deficient in at least amino acids, but are deficient in at least oneone

Vegetarians should combine plant products Vegetarians should combine plant products to provide all the essential amino acidsto provide all the essential amino acids


Nutrition:Nutrition:LipidsLipids

Fat, oils, and cholesterol Fat, oils, and cholesterol

Saturated fats (solids at room Saturated fats (solids at room temperature) usually come from temperature) usually come from animalsanimals

Exceptions are palm oil and coconut oilExceptions are palm oil and coconut oil

Contain mostly saturated fatsContain mostly saturated fats

Butter and meats, such as marbled Butter and meats, such as marbled red meats and bacon, contain red meats and bacon, contain saturated fatssaturated fats


Nutrition:Nutrition:VitaminsVitamins

VitaminsVitamins

Organic compounds the body is unable Organic compounds the body is unable to produce, but are required for to produce, but are required for metabolic purposesmetabolic purposes

Must be obtained externallyMust be obtained externally

AntioxidantsAntioxidants

Cellular metabolism generates free Cellular metabolism generates free radicals that carry extra electronradicals that carry extra electron

Vitamins C, E, and A are believed to Vitamins C, E, and A are believed to defend the body against free radicalsdefend the body against free radicals


Nutrition:Nutrition:VitaminsVitamins

Vitamin DVitamin D

Skin cells contain precursor Skin cells contain precursor cholesterol moleculecholesterol molecule

Converted to vitamin D after UV Converted to vitamin D after UV exposureexposure

Activated into calcitriol that regulates Activated into calcitriol that regulates calcium uptake and metabolismcalcium uptake and metabolism


Nutrition:Nutrition:Fat Soluble Vitamins Fat Soluble Vitamins

Green leafy Green leafy vegetables, vegetables, cabbage, cabbage, cauliflowercauliflower

Clotting of blood, Clotting of blood, bone metabolismbone metabolism

Vitamin Vitamin KK

Green leafy Green leafy vegetables, vegetables, whole grainswhole grains

Strengthening of Strengthening of red blood cell red blood cell membranemembrane

Vitamin EVitamin E

Dairy products, Dairy products, tuna, eggstuna, eggs

Health of bones Health of bones and teethand teeth

Vitamin Vitamin DD

Deep green or Deep green or yellow yellow vegetables, dairy vegetables, dairy productsproducts

Vision; health of Vision; health of skin, hair, bones, skin, hair, bones, and sex organsand sex organs

Vitamin Vitamin AA


Nutrition:Nutrition: Water Soluble Vitamins Water Soluble Vitamins

Citrus fruits, Citrus fruits, tomatoestomatoes

Collagen formationCollagen formationVitamin CVitamin CMost foodsMost foodsEnergy metabolism Energy metabolism Pantothenic Pantothenic

acid acid

Green leafy Green leafy vegetables, nuts, vegetables, nuts, whole grainswhole grains

Formation of red Formation of red blood cells, DNA, blood cells, DNA, and RNA and RNA

Folic acid Folic acid Eggs, most foodsEggs, most foodsCarbohydrate Carbohydrate

metabolism metabolism Biotin Biotin

Meats, dairy Meats, dairy foodsfoods

Red blood cell Red blood cell formation formation

Vitamin BVitamin B1212

Meats, fish, Meats, fish, whole grainswhole grains

Amino acid Amino acid metabolism metabolism

Pyridoxine Pyridoxine (B(B66) )

Organ meats, Organ meats, whole grainswhole grains

Energy metabolism Energy metabolism Niacin (BNiacin (B33) )

Whole grains, Whole grains, milk, green milk, green vegetablesvegetables

Energy metabolism Energy metabolism Riboflavin Riboflavin (B(B22) )

Pork, whole Pork, whole grainsgrains

Carbohydrate Carbohydrate metabolism metabolism

Thiamine (BThiamine (B11) )


Nutrition:Nutrition:Major MineralsMajor Minerals

Whole grains, green leafy vegetables

Protein synthesisMagnesium (Mg)

Table saltWater balanceChlorine (Cl)

Table saltNerve conduction, pH balance

Sodium (Na)

Many fruits and vegetables

Nerve conduction, muscle contraction

Potassium (K)

Meat, dairy products, whole grains

Strong bones and teeth

Phosphorus (P)

Dairy products, green leafy vegetables

Strong bones and teeth, nerve conduction, muscle contraction

Calcium (Ca)


Nutrition:Nutrition:Trace MineralsTrace Minerals

Iodized table salt, seafood

Thyroid hormone synthesis

Iodine (I)

Seafood, whole grains, legumes

Hemoglobin synthesis

Copper (Cu)

Fluoridated drinking water, tea

Strong bones and teeth

Fluorine (F)

Whole grains, legumes, eggs, green leafy vegetables

Hemoglobin synthesis

Iron (Fe)

Whole grains, legumes, meats

Wound healing, tissue growth

Zinc (Zn)


ReviewReviewDigestive TractsDigestive Tracts

Incomplete versus Complete TractsIncomplete versus Complete TractsContinuous versus Discontinuous Continuous versus Discontinuous FeedersFeeders

Dentition Among MammalsDentition Among MammalsHuman Digestive TractHuman Digestive Tract

MouthMouthStomachStomachSmall IntestineSmall IntestineAccessory OrgansAccessory OrgansLarge IntestineLarge Intestine

Digestive EnzymesDigestive EnzymesNutritionNutrition

Digestive Systems and Nutrition

Ending Slide Chapter 36

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Digestive Systems and Nutrition Chapter 36. Digestive Systems and Nutrition 2Outline Digestive Tracts Incomplete versus Complete Tracts Continuous