Chapter 18Chapter 18

The Digestive SystemThe Digestive System

Ch 18.1Ch 18.1 - Nutrition - Nutrition

A. Your body needs nutrients found in A. Your body needs nutrients found in foodsfoods

1. 1. NutrientsNutrients provide energy and provide energy and materials for cell developmentmaterials for cell development

2. You need 2. You need energyenergy for every activity for every activity and to maintain a steady internal and to maintain a steady internal temperaturetemperature

B. Classes of NutrientsB. Classes of Nutrients

1. 1. ProteinsProteins

a) Used for replacement and repair of a) Used for replacement and repair of body cells and for growthbody cells and for growth

b) Made up of amino acidsb) Made up of amino acids

c) Essential amino acids supplied by c) Essential amino acids supplied by foodfood

d) Found in eggs, milk, cheese and d) Found in eggs, milk, cheese and meatmeat

2. 2. CarbohydratesCarbohydrates

a) Main source of energy for your bodya) Main source of energy for your body

b) Made of carbon, hydrogen and oxygenb) Made of carbon, hydrogen and oxygen

c) Sugars are simple; starch & fiber complexc) Sugars are simple; starch & fiber complex

- - SugarsSugars found in fruits, honey, milk found in fruits, honey, milk

- - StarchesStarches found in potatoes and pasta found in potatoes and pasta

- - FiberFiber found in whole-grains and found in whole-grains and veggiesveggies

3. 3. FatsFats

a) Also called lipidsa) Also called lipids

b) Stores excess energy b) Stores excess energy

c) Helps body absorb vitaminsc) Helps body absorb vitamins

d) Classified as saturated & unsaturatedd) Classified as saturated & unsaturated

- - SaturatedSaturated solid at room temp, clog solid at room temp, clog blood blood vessels and associated with high vessels and associated with high cholesterolcholesterol

- - UnsaturatedUnsaturated liquid at room temp, and liquid at room temp, and not not associated with health risksassociated with health risks

4. 4. VitaminsVitamins

a) Needed for growth, regulating body a) Needed for growth, regulating body functions and preventing diseasefunctions and preventing disease

b) A well-balanced diet usually gives b) A well-balanced diet usually gives your body all the vitamins it needsyour body all the vitamins it needs

c) Two groups: water soluble & fat c) Two groups: water soluble & fat solublesoluble

- - WaterWater: Vitamins B & C: Vitamins B & C

- - FatFat: Vitamins A, D, E & K: Vitamins A, D, E & K

5. 5. MineralsMinerals

a) Inorganic nutrients needed in a) Inorganic nutrients needed in small amountssmall amounts

b) Regulate many chemical reactions b) Regulate many chemical reactions in the bodyin the body

c) Calcium and Phosphorus used c) Calcium and Phosphorus used mostmost

6. 6. WaterWater

a) Required for survivala) Required for survival

b) Cells need water to carry out their b) Cells need water to carry out their workwork

c) Dissolves other nutrientsc) Dissolves other nutrients

d) Human body is about 60% waterd) Human body is about 60% water

e) Lost each day when you perspire, e) Lost each day when you perspire, exhale, and get rid of wastesexhale, and get rid of wastes

C. Food GroupsC. Food Groups

1. Because no food has every nutrient 1. Because no food has every nutrient you need to eat a variety of foodsyou need to eat a variety of foods

2. The 2. The food pyramidfood pyramid is a tool to help is a tool to help people select foods that supply all the people select foods that supply all the nutrients they neednutrients they need

3. Foods that contain the same 3. Foods that contain the same nutrients belong to a nutrients belong to a food groupfood group

4. Five food groups:4. Five food groups:

a) Bread and Cereala) Bread and Cereal

b) Fruitb) Fruit

c) Vegetablec) Vegetable

d) Dairyd) Dairy

e) Meat, Poultry, Fish & Beanse) Meat, Poultry, Fish & Beans

Ch 18.2Ch 18.2 – Digestive System – Digestive System

A. A. DigestionDigestion – process of breaking down – process of breaking down food into small molecules to be food into small molecules to be absorbedabsorbed

1. 1. Mechanical DigestionMechanical Digestion – when food is – when food is physically chewed, mixed and churnedphysically chewed, mixed and churned

2. 2. Chemical DigestionChemical Digestion – when food is – when food is broken down by chemical reactionsbroken down by chemical reactions

B. EnzymesB. Enzymes

1. Type of protein that speeds up 1. Type of protein that speeds up rate of chemical reactions in your rate of chemical reactions in your bodybody

2. Many enzymes are involved in the 2. Many enzymes are involved in the digestion of carbs, proteins and fatsdigestion of carbs, proteins and fats

C. Organs of the digestive systemC. Organs of the digestive system

1. 1. Accessory organs Accessory organs – aid in digestion – aid in digestion but food does not pass through thembut food does not pass through them

a) a) tonguetongue, , teethteeth & & salivary glandssalivary glands

b) b) LiverLiver – produces – produces bilebile for the stomach for the stomach which breaks up ingested fatswhich breaks up ingested fats

c) c) GallbladderGallbladder – small sac that stores – small sac that stores bile produced by the liverbile produced by the liver

d) d) PancreasPancreas – produces – produces insulininsulin which which allows the body to process allows the body to process carbohydrates (sugars)carbohydrates (sugars)

2. 2. Digestive Tract Digestive Tract – organs that food – organs that food does pass through during digestion does pass through during digestion

a) a) MouthMouth – here accessory organs – here accessory organs change food into a soft mass called a change food into a soft mass called a bolusbolus

b) b) EsophagusEsophagus – muscular tube that – muscular tube that moves food to the stomach using moves food to the stomach using waves of muscle contractions called waves of muscle contractions called peristalsisperistalsis

c) c) StomachStomach – muscular bag that digests – muscular bag that digests food mechanically by peristalsis and food mechanically by peristalsis and chemically with digestive solutions of chemically with digestive solutions of HCl acid; food becomes a thin, watery HCl acid; food becomes a thin, watery fluid called fluid called chymechyme

d) d) Small Intestine Small Intestine – nutrients are – nutrients are absorbed from chyme into the blood; absorbed from chyme into the blood; projections called projections called villivilli increase increase surface area for absorptionsurface area for absorption

e) e) Large Intestine Large Intestine – water absorbed from – water absorbed from undigested chyme; peristalsis slows so undigested chyme; peristalsis slows so chyme may remain here as long as 3 chyme may remain here as long as 3 daysdays

f) f) Rectum & Anus Rectum & Anus – end of large – end of large intestine and opening to outside of intestine and opening to outside of body; controls release of remaining body; controls release of remaining solid wastessolid wastes

D. D. BacteriaBacteria live in many organs of the live in many organs of the digestive tract helping to digestive tract helping to break down break down food food and and make vitaminsmake vitamins

ESCHERICHIA COLI is a type of bacteria that lives in the intestinal tract, aiding the digestive process by suppressing the growth of harmful bacteria and synthesizing vitamins.