Next week in lab: Diet analysis Record everything you eat or drink and the amount for 24 hr (1 day) Analyze your diet using fitday.com Print out & bring to lab 1. Food list 2. Calories table & pie chart 3. Nutrition table with %RDA values See details on my website Bring a nutrition facts label from a snack food We ll do the worksheet in lab Ch 8 Digestive System & Nutrition 2 3 Food Processing: 4 stages Another word for eating = Breakdown into smaller molecules =.. Uptake of molecules by cells lining the digestive tract = Digestion: A Closer Look Mechanical digestion Begins the process Involves physical processes like chewing Breakdown of food by digestive enzymes = Disposal of undigested materials = 4 5 Digestion breaks down food: Why is Digestion Important? Molecules small enough for cells to absorb Monomers that can be recombined into new molecules Cheese protein (a polymer of amino acids Amino acid in a specific sequence) monomer Breakdown of protein by human digestive system Amino acids Absorption of amino acids by cells lining the small ; transport via bloodstream to other cells uman protein Cells use amino acids from the cheese and other foods to produce new human proteins 6 Foods are Digested by ydrolysis Carbohydrate Fat Enzyme (pepsin) Enzyme (amylase) Enzyme (lipase) Fatty acid Glycerol Amino acid Sugar 7
A Tour of the uman Digestive System First stop: the mouth Functions in: Eating & chewing = The initial steps of digestion Salivary glands secrete saliva Contains an enzyme that begins starch digestion = Swallowing Why doesn t food go down the wind pipe? During swallowing: A reflex tips the Tongue Pharynx NOT SWALLOWING Trachea (windpipe) open Ball of food Epiglottis up Esophageal Adam s sphincter apple (contracted) Esophagus closed SWALLOWING STARTED Trachea closed Epiglottis down EsophagusTrachea open open SWALLOWING FINISED Epiglottis up Esophageal sphincter (contracted) 8 9 Muscular tube Connects mouth to stomach Moves food by waves of muscular contraction & relaxation = Esophagus Esophageal sphincter (contracted) Food ball Relaxed muscles Contracted muscles Relaxed muscles Stomach 10 The Stomach Can store food for several hours Churns food into a thick soup called Flow in / out of the stomach controlled by Stomach lining secretes gastric juice Contains an enzyme that digests protein = Esophagus Control of flow Small Accordion-like folds allow the stomach to expand. Food particle Stomach lining 11 What Causes Gastric Ulcers? A bacterium that lives in mucus & can cause gastric ulcers = It produces an enzyme that shields the bacterium from the acidity of the stomach What Causes eartburn? Backflow of chyme into esophagus Cl irritates the esophageal wall 12 13
Small Intestine Duodenum First part of the small Site of most digestion Chyme from the stomach mixes with digestive juices from The longest part of the alimentary canal The major organ for digestion & absorption of nutrients Juice that neutralizes stomach acids in the duodenum secreted by the The liver secretes, which: Is stored in the gallbladder elps digest fats 3 regions: 14 15 Absorption of Nutrients Large Intestine In the duodenum, nutrients are: Blood vessels Completely digested Ready to be absorbed Muscle layers Intestinal wall Villi Interior of Nutrient absorption Main portion of the large = Absorbs water Colon of large Produces feces The surface area and capacity for absorption increased by The rectum stores feces Small Rectum Anus Figure 22.14a 16 Nutrition Overview Mouth Ingestion Food into mouth Digestion Mechanical digestion Chewing in mouth Churning in stomach Chemical digestion Saliva in mouth Acid & pepsin in stomach Enzymes in small Absorption Nutrients & water in small in large Elimination Feces formed in large Elimination from anus 17 What are nutrients? Why isn t alcohol a nutrient? What are the main functions of nutrients in your body? What are the 6 types of nutrients & their functions? What is a calorie? What is an essential nutrient? What are micronutrients? Food Stomach Small Large Anus 18 19
What is a Nutrient? Any substance that the body uses to: Provide energy (calories) Regulate body processes Six Types of Nutrients Is alcohol a nutrient? Provides energy (7 Cal/g) No necessary function in the body Toxic in large amounts 20 21 The body is about % water Nutrients Some nutrients supply Found both inside & outside the cells Functions include: elps regulate body temperature Transports nutrients Excretes waste Energy needed to power muscle contraction, maintain body temp & other cell functions 22 23 Calories measure energy One calorie = amount of energy required to raise the temperature of Calories Nutrient Carbohydrate Fat Energy 4 cal/g 4 cal/g 9 cal/g Some Nutrients Regulate Body Processes Vitamins & minerals (the micronutrients) & water Vision Metabolism Iodine is a component of Iron helps transport O 2 Blood pressure 24 25
ow Does the Body Use Carbs &? Primary energy source for the body = carbohydrates Provide undigestible complex carbohydrates = Unsaturated Fatty Acids (Some Double Bonds C=C) Kinds of Reduce eart Disease Risk Dietary fats provide: Energy Fat-soluble vitamins (vitamins A, D, E & K) Essential fatty acids (omega- 3 & omega-6) Long-term energy storage in Saturated Fatty Acids (All Single Bonds C-C) Trans-Fatty Acids (ydrogenated) Not Found Naturally! eighten eart Disease Risk eighten eart Disease Risk 26 27 Cholesterol Found in cell membranes Only found in animal tissues (not in plants) Used to make: LDL & DL Cholesterol DL delivers cholesterol to liver for elimination Protects against heart disease LDL or Lousy cholesterol Transports cholesterol to the cells Contributes to plaques igh levels raise risk of heart disease 28 29 Builds & maintains tissues: Muscle, bone, skin & hair Regulates body functions Many hormones are proteins Protects from illness Antibodies are protein Essential Amino Acids Must be obtained from the diet the body can t synthesize them Different foods contain different essential amino acids Used for energy Sources: 30 31
Micronutrients Essential (can t be made by body) Required in small amounts Vitamins Fat-soluble: Stored in body fat Toxic if consumed in excess -soluble: Calcium, iron, iodine, zinc & others -soluble Vitamins Vitamin C, B-vitamins Need to be consumed regularly Not stored in the body to any extent Excess excreted in urine Very diverse functions B vitamins are involved in 32 33 Good Nutrition Getting the correct nutrients Foods that provide energy Essential nutrients that the body can t make Getting the 34 35 Basic Nutritional Advice Eat a variety of foods including: Eat less Avoid too much junk food Exercise regularly Alcohol: the good, the bad & the ugly People drink to relax, celebrate & socialize armful effects include: 36 37
Effects of Alcohol Alcoholic Liver Disease After just a few days of overconsumption = Fibrosis Cirrhosis Permanent damage Scar tissue has developed 38 39 Which Are Used for Body Structure? Which Nutrients Provide Energy? Vitamins Vitamins 40 omework Which Regulate Body Functions? Record everything you eat or drink and the amount for 24 hr (1 day) Analyze your diet using fitday.com Bring the fitday reports & a nutrition facts label from your favorite snack food to lab next week Test your knowledge Vitamins 41 Answer questions 1, 5, 9, 11-15, 18, 19 at the end of Ch 8 42 43