1. DIGESTION AND NUTRITION

3. Layers of Alimentary Canal Organs Slide 14.13 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.3

5. Chemical Digestion in the Small Intestine Slide 14.23b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.6

6. Processes of the Digestive System Ingestion Propulsion Food Breakdown: Mechanical Digestion Food Breakdown: Chemical Digestion Absorption Defacation

7. Processes of the Digestive System Slide 14.42a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Ingestion – getting food into the mouth  Propulsion – moving foods from one region of the digestive system to another

8. Processes of the Digestive System Slide 14.42b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Peristalsis – alternating waves of contraction  Segmentation – moving materials back and forth to aid in mixing Figure 14.12

9. Processes of the Digestive System Slide 14.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Mechanical digestion  Mixing of food in the mouth by the tongue  Churning of food in the stomach  Segmentation in the small intestine

10. Processes of the Digestive System Slide 14.44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Chemical Digestion  Enzymes break down food molecules into their building blocks  Each major food group uses different enzymes  Carbohydrates are broken to simple sugars  Proteins are broken to amino acids  Fats are broken to fatty acids and alcohols

11. Processes of the Digestive System Slide 14.45 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Absorption  End products of digestion are absorbed in the blood or lymph  Food must enter mucosal cells and then into blood or lymph capillaries  Defecation  Elimination of indigestible substances as feces

12. Processes of the Digestive System Slide 14.46 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.11

13. Nutrition and Healthy Choices

14. Nutrition Slide 14.63 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Nutrient – substance used by the body for growth, maintenance, and repair  Categories of nutrients  Carbohydrates  Lipids  Proteins  Vitamins  Mineral Water- no calories, no nutrition

15. Dietary Sources of Major Nutrients Slide 14.64 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Carbohydrates  Most are derived from plants  Exceptions: lactose from milk and small amounts of glycogens from meats  Lipids  Saturated fats from animal products  Unsaturated fats from nuts, seeds, and vegetable oils  Cholesterol from egg yolk, meats, and milk products

16. Dietary Sources of Major Nutrients Slide 14.65 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Proteins  Complete proteins – contain all essential amino acids  Most are from animal products  Legumes and beans also have proteins, but are incomplete  Vitamins  Most vitamins are used as cofactors and act with enzymes  Found in all major food groups

17. Dietary Sources of Major Nutrients Slide 14.66 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Minerals-Inorganic- non-living matter  Play many roles in the body  Ex:  Calcium- muscle and bone  Iron- Blood  Most mineral-rich foods are vegetables, legumes, milk, and some meats

18. Carbohydrate Metabolism Review Slide 14.68 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The body’s preferred source to produce cellular energy (ATP)  Glucose (blood sugar) is the major breakdown product and fuel to make ATP Figure 14.16

19. Cellular Respiration Review Slide 14.69 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Oxygen-using events take place within the cell to create ATP from ADP  Carbon leaves cells as carbon dioxide (CO 2 )  Hydrogen atoms are combined with oxygen to form water (oxygen is required as final electron acceptor)  Energy produced by these reactions adds a phosphorus to ADP to produce ATP  ATP can be broken down to release energy for cellular use

20. Metabolic Functions of the Liver Slide 14.78 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Glycogenesis  Glucose molecules are converted to glycogen  Glycogen molecules are stored in the liver and body tissues.  Glycogenolysis  Glucose is released from the liver after conversion from glycogen  Gluconeogenesis  Glucose is produced from fats and proteins

21. Metabolic Functions of the Liver Slide 14.79 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.20 Glycogenesis

22. Regulation of Food Intake Slide 14.84 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Body weight is usually relatively stable  Set Point- Energy intake and output remain about equal  Mechanisms that may regulate food intake  Levels of nutrients in the blood  Hormones  Body temperature  Psychological factors

23. Total Metabolic Rate (TMR) Slide 14.86 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Total amount of kilocalories the body must consume to fuel ongoing activities  TMR increases with an increase in body activity  TMR must equal calories consumed to maintain homeostasis and maintain a constant weight

24. Metabolic Rate and Body Heat Production Slide 14.85a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Basic metabolic rate (BMR) – amount of heat produced by the body per unit of time at rest  Factors that influence BMR  Surface area – small body usually has higher BMR  Gender – males tend to have higher BMR  Muscle mass increases BMR

25. Metabolic Rate and Body Heat Production Slide 14.85b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Factors that influence BMR (continued)  Age – children and adolescents have a higher BMR  The amount of thyroxine produced is the most important control factor  More thyroxine means higher metabolic rate (high metabolism)

26. Body Temperature Regulation Slide 14.87a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Most energy is released as foods are oxidized  Most energy escapes as heat

27. Body Temperature Regulation Slide 14.87b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The body has a narrow range of homeostatic temperature  Must remain between 35.6° to 37.8°C (96° to 100° F)  The body’s thermostat is in the hypothalamus  Initiates heat-loss or heat-promoting mechanisms

28. Heat Promoting Mechanisms Slide 14.88 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Vasoconstriction of blood vessels  Blood is rerouted to deeper, more vital body organs  Shivering – contraction of muscles produces heat

29. Heat Loss Mechanisms Slide 14.89 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Heat loss from the skin via radiation and evaporation  Skin blood vessels and capillaries are flushed with warm blood  Evaporation of perspiration cools the skin

30. Body Temperature Regulation Slide 14.90 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14.21 Find an afferent pathway in diagram. Find an efferent pathway in diagram.

31. Healthy Choices for Life The choices you make in taking care of your body now can affect you for the rest of your life!

32. Set Point Mentally, think about how much you weigh. This doesn’t really change a lot, no matter what you do. This is your SET POINT. –If you eat more, body burns excess calories –If you eat less, body conserves fat. So, a very low fat diet can lead to weight gain.

33. Weight Loss Childhood fat intake determines the number of fat cells in the adult. Fat cells in obese animals (humans included) are larger than in non-obese animals. Fat that is eaten becomes body fat more readily than protein or carbohydrate. ? The only way to lower the SET POINT is to combine diet and exercise.

34. Did you know we have two sets of nostrils? A second set of nostrils are in the back of the mouth. Taste is largely a function of smell

35. Diet and Exercise Discuss what is meant by healthy diet and exercise. –Generally, reduced calories overall. Lots of fruit and vegetables. Include fiber. –For maintenance-30 minutes of more aerobic exercise 3 times per week (or more). –For weight loss- 1 hour per day 5-7 times/ week.

36. Arteriosclerosis What is it? –End stage of atherosclerosis –Hardening of the arteries –Scar tissue develops in tunica media of artery. –Leads to myocardial infarct, stroke, kidney failure. Normal Artery Fat Build Up

37. Fat Cells Fat cells have been shown to make hormones. –Ovulation and menstruation cannot occur with too small of a body fat index. –High body fat can make too many hormones, contributing to stroke, heart attack, hunger, and diabetes.

38. Eating disorders What do you know about anorexia nervosa? How does it harm the person? Do you know anyone who is anorexic?

39. Eating disorders What do you know about bulemia? How does it harm the person? Do you know anyone who is bulemic?

40. Developmental Aspects of the Digestive System Slide 14.91 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  The alimentary canal is a continuous tube by the fifth week of development  Digestive glands bud from the mucosa of the alimentary tube  The developing fetus receives all nutrients through the placenta  In newborns, feeding must be frequent, peristalsis is inefficient, and vomiting is common

41. Developmental Aspects of the Digestive System Slide 14.92a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Teething begins around age six months  Metabolism decreases with old age  Middle age digestive problems  Ulcers  Gall bladder problems

42. Developmental Aspects of the Digestive System Slide 14.92b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Activity of digestive tract in old age  Fewer digestive juices  Peristalsis slows  Diverticulosis (mucosa protrudes through colon wall) and cancer are more common

43. Digestive Disorders Colitis- Inflammation of the Large Intestine (colon, cecum or rectum) and is often an indication of disease; ex: Crohn’s Disease –Signs of colitis may include: abdominal pain, diarrhea, increased frequency of bowel movement. Gastroenteritis-Stomach flu –Vomiting, diarrhea, abdominal pain –Caused by a virus (not influenza, “the flu”)