digestive & urinary systems & nutrition course notes

April 19, 2012

Digestive System

April 19, 2012

Digestion Basics

1. Mouth: Saliva has an enzyme that begins to break down starch (bolus)

2. Esophagus: Muscular tube

3. Stomach: Acids and enzymes digest food further (chyme)

4. Small intestine: Enzymes produced here and by the pancreas break down food further and nutrient molecules are absorbed into the blood across the walls of the small intestine. 20' in length: duodenum, jejunum, ileum

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5. Large Intestine: Unabsorbed food moves into here and water is removed and some vitamins from undigested food.

6. Rectum: Waste is expelled from the body.

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Urinary System

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* Nutrition is the study of...

- Food and how the body uses food

- How and why we make food choices

- Nutrients foods contain

* What are benefits of good nutrition?

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* 6 Classes of Nutrients

- Carbohydrates

- Fat

- Protein

- Vitamins

- Minerals

- Water

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Carbohydrates

* Provide 4 cal/g (with 1 exception)

* Include:

- sugars = "simple"

- starches = "complex"

- fiber (The weird carb, has 0 calories)

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*What happens when you consume carbohydrates?

1. Breaks down into glucose

2. If blood glucose too high, pancreas reacts and excess is stored in liver and

muscles as glycogen

3. When glycogen stores are full, it converts to fat

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Two Types of Fiber (the weird carb)

1. Soluble

- Dissolves in water

- Cholesterol

2. Insoluble

- Does not dissolve in water

- Solid waste

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Fat

* Provide 9 cal/g

* When too much in blood, it's stored as triglycerides (3 fatty acids + 1 glycerol) in the fat cells

* 2 Types of fat

- Saturated: * Usually solid at room temperature * Derived from animal foods

- Unsaturated:* Usually liquid at room temperature* Derived from plants

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Cholesterol (assoc. with saturated fat)

* Made by the body and obtained through animal foods

* 2 Types:

- LDL (bad): Can cause plaque formation in blood vessels

- HDL (healthy): Carries cholesterol to liver to be removed from blood

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Protein

* Provides 4 cal/g

* Protein builds, repairs, and maintains body tissues

* Protein is found in: - Muscles - Bones - Blood - Hormones

* Amino acids = the building blocks that make up protein

- Nonessential amino acids: produced by body (11)

- Essential amino acids: must obtain through diet (9)

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Complete Protein Incomplete Protein

From animal sources From plant sources

Contain all essential amino acids

Do not contain all essential amino acids

Ex: Meat, fish, chicken, turkey, milk, yogurt, eggs

Ex: Nuts, seeds, beans

2 Types of Protein

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The Vegan Diet

* Vegan = Person whose diet does not include foods derived from animals.

* How do they get complete protein?

* Protein Loading = Eating strategy in which extra protein is eaten to increase muscle size.

* Extra protein does not increase muscle size. Resistance exercise increases muscle size. If eat more protein than body needs, it's stored as fat.

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U.S. RDA for protein = .36 g x body weight

weight (lbs) protein RDA (g) 100 36120 43140 50160 58

(Milk carton = 8 g)

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Vitamins

* Provide 0 cal/g

* Fat soluble vitamins (A, D, E, & K) can be stored in the body

- Toxic if overdose on dietary supplements containing FSV (Hypervitaminosis)

* Water soluble vitamins (B & C) cannot be store in the body in significant amounts

- Not toxic because can excrete excess WSV

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Minerals

* Provide 0 cal/g

* Make up 5% body weight

* Macrominerals: Found in body in amounts > 5 g

- Electrolytes: Sodium, Potassium, Chlorine

* Trace Minerals: Found in body in amounts < 5 g

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Water

* Provide 0 cal/g

* Consume 8+ glasses/day (and 2 glasses/lb lost after exercise)

* Makes up ~60% of our bodies

* Lost through:- Urine and solid waste- Breathing- Skin

* Dehydration = Water consumed is less than body uses

April 19, 2012

The Food Label