1. Human Body Systems
Digestion & Human Nutrition

2. Why do we eat?
 We eat to supply our cells with the
molecules needed to sustain life.

3. Remember These?
Organic Compounds found in Living Cells
Molecule Building Blocks Examples Function in Cell
quick energy - ATP
saccharides glucose, cellulose, starch,
Carbohydrates (sugars) fructose, lactose, amylose
(fuel for cell
processes)
stored energy,
triglycerides, phospholipids,
Lipids fatty acids
hormones
cell membrane structure,
chemical messengers
Signaling (receptors)
hemoglobin, antibodies, Structural (microtubules)
enzymes, collagen, iron,
Proteins amino acids microtubules, membrane Storage (iron/hemoglobin)
receptors, flagella, muscles, Contractile (actin/myosin)
etc. Defensive (antibodies)
Enzymes (chem. reaction)
Transportation
stores genetic
Nucleic Acids nucleotides DNA & RNA
"blueprints"

4. Food Basics
 Basic components of food:
 Carbohydrates (simple & complex)
Organic  Proteins
molecules  Fats
 Vitamins
 Minerals
 Fiber
 Water
 Non-food additives in
processed foods:
 artificial colors & sweeteners
(dyes, aspartame, HFCS)
 chemical preservatives
(nitrates, BHT/BHA)
 flavor enhancers
(MSG)

5. What Are Calories?
 Calories are a unit of
thermal energy (heat)
 Food Calories measure
the amount of energy
food gives your body
The average adult needs
~ 2,000 Cal per day.
 Calories measure the thermal energy required to heat water
 1 Calorie (capital) = 1,000 calories = 1 kcal
 1 gram of water = 1 cubic centimeter (cc)
 1 kg water = 1,000 cc = a 10x10x10 cm cube of water

6. Calories (kcal)
110
105
210 35
160
150
220
150 13
280
210 70

7. RDA - Recommended Daily Allowance
Nutrient Needed Amount Needed Food with This Nutritional Value
Calories 2000 calories •4 Taco Bell Tacos
•8 Pancakes with butter & syrup
•1 ½ cheese pizzas
Total Fat 65 grams •1 ¼ cups of Trail Mix (with chocolate chips)
Fat: 30% •1 ½ McDonald's sausage egg biscuit
1g = 9cal •6 Fried Chicken Wings
Sodium 2400 milligrams •1 teaspoon of table salt
•3 dill pickles
Carbs: 60% Total Carbohydrate 300 grams •2 cups of White Rice
•3 cups of Grape Juice
1g = 4cal
Dietary Fiber 25 grams •1 ½ cups of Refried Beans
•3 ½ cups of Raisin Bran cereal
Protein 50 grams •1 ½ cups of Cottage Cheese
Protein: 10% •3 Chicken Drumsticks
1g = 4cal •1 Cup of Peanuts
Vitamin C 60 •1 Kiwi Fruit
•1 Apple or Orange
Calcium 1200 milligrams •1 glass of Skim Milk
•10 cups of Beans
Iron 12 milligrams •2 cups of Spinach
•450 g of Beef

8. Organic Molecules
 Carbohydrates – fuel for all
cell functions (ATP)
 60% of calories
 Fats (lipids) – stored
energy, insulation &
membrane structure
 30% of calories
 Proteins – building
materials for many
cell parts & products
 10% of calories

9. Carbohydrate Needs
 ~ 300 g daily needed for survival (60%)
 1g Carbohydrate = 4 Calories
 broken down into glucose for ATP
 Simple Carbohydrates
 taste sweet
 monosaccharides & disaccharides
 listed as "Sugars" on food labels
 Complex Carbohydrates
 plant starches
 polysaccharides (long chains of glucose)

10. Carbohydrates & Insulin
 Simple Carbohydrates
 digested easily (already broken down)
 glucose enters bloodstream quickly
 30 calories per minute
 Complex Carbohydrates
 takes longer to break down (digest)
 glucose enters bloodstream slowly
 2 calories per minute
 Insulin
 special protein secreted by pancreas
 release is triggered blood sugar levels
 insulin signals cells to absorb glucose
 blood sugar lowers after insulin release
 sugar overload causes blood sugar
fluctuations because of lag time
 simple carbohydrate "sugar rush"
 hypoglycemia symptoms 2-5 hrs. later

11. Carbohydrates
26g
27g
33g 8g
34g
0g
51g
25g 2g
35g
45g 0g

12. Protein Requirements
 ~ 50 g daily needed for survival (10%)
 1g protein = 4 Calories
 broken down into 20 different amino Carboxylic Amino
acids to build & repair cell components acid group group
 almost 20% body mass is protein
 Non-essential amino acids
 body can create these from other molecules
 i.e. Asparagine, Cysteine, Proline, Tyrosine
 Essential amino acids
 must get from eating foods containing them
 i.e. Histidine, Lysine, Methionine, Tryptophan

13. Protein Sources
 Animal Proteins
 meat, milk, eggs, fish
 "complete"
 contain all essential amino acids
 Vegetable Proteins
 beans, nuts, soy (tofu/edimame), grains
 missing some essential amino acids
 eating a variety can provide what is
needed

14. Protein
2g
1g
5g 1g
6g
24g
0g
8g 2g
4g
7g 7g

15. Do You NEED Fat?
 ~ 65 g daily needed for survival (30%)
 1g fat = 9 Calories
 break down into glycerol and fatty acids
 immediate or stored energy
 cell membrane-building
 to allow absorption of some vitamins
 Essential fatty acids
 must get these from food because your
body can't make these molecules
 Too much fat
 average American diet has too much fat
 problems associated with obesity:
 heart disease
 diabetes
 cancer
 stroke
 many others

16. "Good" & "Bad" Fat
 Unsaturated fat ("better")
 liquid at room temperature
 most vegetable (plant) oils
 olive oil is a mix of fats
 healthier because they are less harmful
than saturated fat (especially monounsaturated)
 Saturated fat ("bad")
 solid at room temperature
 lard, shortening, & animal fat
 Trans-fatty acids
 hardened vegetable oil
 "hydrogenated oils"
 raise LDL ("bad" cholesterol) levels

17. Fat (lipids)
.5g
.5g
2g 0g
2g
6g
0g
3g 0g
14g
1g 5g

18. Vitamins
 Vitamins are small molecules your body needs to keep itself
running properly
 Found in fresh, "whole" foods
 Processing destroys vitamins, so many processed foods are
"fortified" with man-made vitamins.

19. What Do Vitamins Do?
 Water Soluble
 readily absorbed into bloodstream
 kidneys filter out excess
 B Vitamins
 Thiamine, Riboflavin, Niacin, Pyridoxine, B12, Folic Acid
 Vitamin C (ascorbic acid)
 immune system, longevity, lowering cholesterol
 Pantothenic acid
 healthy skin, hair, eyes, liver & nervous system
 Biotin
 helps your body break down food and use it for energy
 Fat Soluble
 only absorbed with fat
 possible to overdose since kidneys can't filter out
 Vitamin A
 eyesight, healthy skin & cancer prevention
 Vitamin D
 strong teeth & bones (calcium absorption)
 Vitamin E
 fighting toxins (antioxidant)
 Vitamin K
 blood clotting, bone cell production

20. Minerals
 Elements our bodies must have in
order to create other needed
molecules
 Calcium - used by teeth, bones
 Chlorine, Chromium, & Copper
 Fluoride - strengthens teeth
 Iodine - used to create the hormone
thyroxine
 Iron - transports oxygen in red blood
cells
 Magnesium, Manganese, &
Molybdenum
 Phosphorus
 Potassium - important ion in nerve
cells
 Selenium, Sodium
 Zinc - healthy immune system &
digestion

21. Sodium (Na)
 A mineral; enters our diet as salt (NaCl)
 Too much sodium causes water to stay in
the bloodstream, causing hypertension
 diffusion = low to high concentration
 hypertension = high blood pressure
 heart disease
 stroke
 osteoporosis
 stomach cancer

kidney disease
Less than 2400 mg of
sodium is the RDA.

22. Sodium (in mg)
0
1
105 78
320
350
0
570 48
140
0 70

23. McDonalds - Calories•Fat•Sodium
350•19•750
250•9•480 (burger only)
w/ fries: 490•20•640
470•30•900
360•16•800
520•26•1100 (burger only)
560•37•1400
350•9•820 meal: 1290•51•1540

24. Taco Bell - Calories•Fat•Sodium
550•22•1270
200•11•370 780•42•1380
370•11•960
650•39•1300 970•58•1670

25. Subway - Calories•Fat•Sodium
Black Forest Cheese adds 5 g fat
Ham (no Mayo adds 12g fat
cheese)
Ranch adds 110 cal
290•4½•830
Mustard adds 5 cal
(and no fat)
Spicy
Italian
480•24•1520 cheese or
(without Veggie
condiments) Delight
230•2½•310
(no cheese or
condiments)
Chicken & Bacon
Ranch Melt
Tuna (no cheese)
470•24•620
Chips, cookies,
& specialty
Sweet Onion breads will add
fat, calories and
570•28•1080 Teriyaki sodium as well.
(no cheese or extra 380•4½•900

26. Water
 Lost through:
 urine (kidneys)
 sweat
 breathing
 40 oz/day needed to
replenish (minimum)
 more needed when hot,
exercising, or ill
 Many fruits have surprisingly
high water content
 Caffeinated beverages actually
deplete the body's water

27. Fiber
 Plant materials we eat that our bodies cannot digest
 fiber passes straight through the digestive system
 ~ 25 - 35 g recommended each day for healthy digestion
 expands in stomach, creating a longer "full" feeling
 aids digestion (stimulates smooth muscle, prevents
constipation)
 lowers blood cholesterol, slows
digestion to stabilize blood sugar
Processed foods strip away most of the fiber
 Hemicellulose
 found in the hulls of grains
 wheat, oats, rice, bran, barley, corn
 Cellulose
 structural component of plants (especially
skins/peels, legumes)
 a complex carbohydrate which some animals
can digest
 Pectin
 found most often in fruits
 "water-soluble fiber" which forms a gel

28. A Well-Balanced Diet
 A healthy diet contains:
 fresh, whole (unprocessed) foods
 low-fat, low-salt sources of protein
 vitamin & mineral-rich foods
 enough Calories (but not too many)
a balance of fats, protein, &
carbohydrates
 a variety of
fruits,
vegetables
& grains

29. Good vs. Bad Nutrients
Good Bad
Unprocessed, high in fiber, Refined, processed, artificial
Carbohydrates "whole" natural foods additives - empty calories
Fruits, vegetables, beans, whole grain candy, baked goods with refined white
examples:
breads/cereals/pastas flour, white pastas, soda pop, sugary juice
Mono- and Poly-unsaturated
Fats fats, Omega fatty acids
Saturated and Trans fats
nuts, seeds, avocado, canola, olive, & meat, dairy, egg yolks, seafood, coconut
examples:
safflower oils, fish, corn, soy (small bits) & palm kernel oils, packaged & fried foods
Low fat animal sources,
Protein unprocessed, vegetables
High fat, additives, salty
Nuts, seeds, lean beef/chicken/pork, egg bacon, hot dogs, fried shrimp, chicken
examples: whites, fish, grain burgers, hummus, nuggets, beef jerky, sausage, whole milk,
lentils, beans, mozzarella cheese, yogurt cheddar cheese
 Virtually all foods contain some of each type of nutrient
 1 cup cooked rice has 5g protein & spaghetti has about 7g protein
 1 cup cooked pinto beans has almost 16 g protein AND 45 g carbohydrate
 2 tablespoons of peanut butter has 8 g protein, 7 g carbohydrate and 16 g fat

30. Understanding Nutrition Labels

31. Review

32. Quick Review: Bones
 How many bones do humans have? 206
 What five jobs do bones do?
- structural support, attachment of muscles for
movement, protection of organs, produce blood cells,
& store minerals
 Which bones comprise the appendicular
skeleton? - shoulders, arms, hips, legs,
 Give an example of each: long, flat, short
and irregular bone.
 Describe each of the 3 tissues that form
bones. - compact, spongy, marrow
 Give an example of each type of joint:
hinge, ball & socket, saddle/gliding, pivot.
H: jaw/knee; B&S: hip/shoulder; S: thumb; P: neck
 What do cartilage, ligaments and tendons
do? Cartilage: pads joints
Ligaments: connect bone to bone
Tendons: connect muscle to bone or other muscle

33. Quick Review: Muscles
 How many muscles do humans have?
almost 650
 Name 3 kinds of muscle tissue.
Cardiac, Skeletal, Smooth
 What are voluntary muscles?
muscles you control (skeletal muscles)
 How do muscles work?
in pairs, they only pull, each attaches to 2 bones,
fibers are bundled together, individual cells contract
 What are actin & myosin?
microtubules slide alongside each other to shorten the muscle fiber
 List some of the harmful affects of
steroid abuse.
stunted growth, hair loss, hair growth, high blood pressure,
liver tumors, infertility, aggression, mood swings, stroke, heart,
attack, acne, breast growth

34. Quick Review: Skin
 What does skin protect against?
physical damage, disease, dehydration, heat & cold
 Name the 3 skin layers.
Epidermis, Dermis, Hypodermis
 What is found in each layer?
Epidermis - tight, thin sheets of cells, melanocytes, touch/pain/heat
receptors
Dermis - hair, sweat & oil glands, nerves, blood vessels, collagen/elastin
Hypodermis - fat for protection/insulation
 How does skin regulate body
temperature? sweat glands & hair/pili
 List some environmental factors that
can cause dermatitis, acne, or skin
cancer?
hormones, grease from cosmetics or environment, contact,
stress, soaps, dryness, allergens, sunlight, fair-skinned,

35. Review: Digestion
 What organs comprise the digestive
system? Mouth, salivary glands, esophagus, stomach, gall
bladder, liver, & pancreas, small intestine, colon
 What are the two primary purposes of the
digestive system?
1 - extract nutrients & water from
food/beverages
 In whichstore and does most of the water in
2 - organ eliminate leftover waste
food get absorbed into the bloodstream?
products
Colon (large intestine)
 What two structures keep chyme
contained in the stomach until ready for
release?
Esophageal & pyloric sphincters
 How does the liver aid in digestion?
makes bile, which breaks down fat (lipid molecules)
 What structures in thefrom blood (alcohol/drugs)
removes ingested toxins small intestine
increase the diffusion of nutrients into the
bloodstream?
 villi: folds in the intestinal wall
 microvilli: finger-like projections of cell membranes

36. Review: Excretion
 Organs of the Urinary Tract
 Blood flows into kidneys
 Nephrons clean blood
 Filtered blood flows back into
circulatory system
 Waste products flow down thin
tubes called ureters
 Urine is stored in the bladder
 Urine exits body via urethra

37. Carbohydrate Digestion, 1g = 4cal
1. Saliva begins to break down sugars Polysaccharide Chain
 simple sugars break down quickly
 complex carbohydrates take longer to
digest (fiber & starch)
2. In stomach, most carbs have already been
digested into single or double sugars Disaccharides
(mono- or disaccharides)
 some glucose diffuses into bloodstream
here (active transport)
3. Intestines absorb remaining carbohydrates Monosaccharides
 most sugars are first sent to the liver for
conversion to into glucose and release into
the bloodstream
 excess glucose is stored in the liver (up to i.e. galactose, fructose
100g) or muscles (up to 500g) as glycogen
 with the help of insulin, blood glucose is
transported into cells for ATP production
glucose  ATP
4. Carbs that cannot be used by cells or
stored as glycogen are converted into fat

38. Fat Digestion, 1g = 9cal
 mechanical digestion & bile salts chop up Big Lipid
big molecules in intestines Molecule
 emulsifiers & smooth muscle peristalsis
break down big lipids into smaller droplets
 pancreatic juices then surround fats as
they are further broken up
 monoglycerides and fatty acids diffuse into
microvilli cells
Fatty
 smooth ER & Golgi process molecules
before sending them into bloodstream Monoglycerides Acids
 fat-soluble vitamins (A, D, E, & K) tag along
with fats as they cross membranes
 body uses or stores for energy, to produce
hormones, & to replace cell structures

39. Protein Digestion, 1g = 4cal
Whole Protein Chain
 Stomach acid and enzymes (pepsin)
break long chains into short segments
Peptide
Fragments
 Pancreatic juices break bonds further
in the intestine
 Amino acids enter intestinal wall cells
via active transport or endocytosis
 bloodstream carries to cells Amino Acids
 DNA provides instructions to build
antibodies & hemoglobin, muscle
fibers, collagen in skin, & other cell
structures