1. Anatomy and Physiology
Marieb’s Human
Anatomy and Physiology
Ninth Edition
Marieb w Hoehn
Chapter 24
Nutrition & Metabolism
Lecture 12
Part 1: Overview, Carbohydrates, and Fats
Slides 1-15; 80 min (with review of syllabus and Web sites) [Lecture 1]
Slides 16 – 38; 50 min [Lecture 2]
118 min (38 slides plus review of course Web sites and syllabus)

2. Nutrients
Nutrients – chemical substances supplied by the environment required for survival (used for growth, repair, or maintenance of the body)
Macronutrients
carbohydrates
proteins
fats
Micronutrients
vitamins
minerals
Essential Nutrients
human cells cannot synthesize
include certain fatty acids, amino acids, vitamins

3. Overview of General Metabolic Pathways
Overall goal of catabolism: generate a pool of 2- or 3-carbon molecules and ATP
 Lipo-genesis
Glycogenolysis 
 Glycogenesis
Lipolysis 
Pyruvate is used to synthesize amino acids and Acetyl CoA
Pyruvate can also be used to synthesize glucose via gluconeogenesis.
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

4. Carbohydrates Sources Excesses lead to sugars (simple) obesity
starches (complex) - usually from plant sources
glycogen (complex) in meats
cellulose (complex) is indigestible fiber
Excesses lead to
obesity
dental caries
nutritional deficits
Deficiencies lead to
metabolic acidosis
weight loss
In body: about 325 g. muscle glycogen, g of liver glycogen, and g of blood glucose.
Avg American eats about 100 lbs of sugar per year (60 lbs sucrose, 40 lbs corn syrup) compared with 4 lbs per year about a century ago.
RDA - The RDA, the estimated amount of a nutrient (or calories) per day considered necessary for the maintenance of good health by the Food and Nutrition Board of the National Research Council/ National Academy of Sciences. The RDA is updated periodically to reflect new knowledge. It is popularly called the Recommended Daily Allowance.
Recommended (Dietary) Daily Allowance (RDA) is g *

5. Utilization of Carbohydrates
Glucose is the body’s CHO energy source
Figure from: Hole’s Human A&P, 12th edition, 2010

6. Lipids Sources meats eggs milk lard plant oils Excesses lead to
obesity
increased serum cholesterol
increased risk of heart disease
Deficiencies lead to
weight loss
skin lesions
hormonal imbalances
RDA is g ( 30% of calories)
( 10% saturated fat)
Fats generally take the longest to digest. Why?

7. Utilization of Lipids
Figure from: Saladin, Anatomy & Physiology, McGraw Hill, 2007
Via what structures is fat absorbed into the circulation from the digestive tract?
In the absence of sufficient CHO, oxaloacetic acid (the ‘pickup’ molecule for Acetyl CoA in the TCA cycle) is converted to glucose and is no longer available to bind with Acetyl CoA. This causes acetyl CoA to be converted into ketone bodies resulting in ketoacidosis.
Know these terms (see table of these terms later in this lecture)
Oxaloacetic acid *

8. Beta-Oxidation of Fatty Acids
Mitochondrion
Long chain fatty acids (FA) require carnitine for transport into mitochondria
FA are broken down in a step-wise manner, 2 carbons at a time in beta-oxidation
Oxidation of FA yields about times the energy from a comparable amount of glucose

9. Energy Values of Food
Calorie (kilocalorie, big calorie) – amount of heat needed to raise the temperature of 1 kg of water by 10 C
Carbohydrates
4.1 Calories per gram
Diet is 2000 Calories. What is the maximum number of grams of fat that should be taken in daily?
Proteins
4.1 Calories per gram
How many grams of fat are there in a Whopper with cheese and a small order of french fries?
Lipids
9.5 Calories per gram
Know this - you can round these off to the 4, 4, and 9)

10. So, what’s going on here? 14g CHO x 4 cal/g = 56 cal
Why do the calories for 12 oz. of this beer seem to be more than what you would suppose based on the CHO and protein content?
14g CHO x 4 cal/g = cal
1g protein x 4 cal/g = 4 cal
Total cal
Alcohol! About 7 cal/g

11. Lipoprotein Traffic TG-rich Cholesterol-rich
Figure From: Martini, Anatomy & Physiology, Prentice Hall, 2001
TG-rich
Cholesterol-rich
*Cholesterol can be manufactured from Acetyl-CoA
Note the role of HDLs as scavengers of tissue/blood cholesterol.

12. Summary of Lipoproteins
Designation
Origin
Action
Chylomicron
GI tract
Transports dietary fats (mainly triglycerides) to liver for processing
Very Low Density Lipoprotein (VLDL)
Liver
Transports triglycerides from liver to adipose cells
Low Density Lipoprotein (LDL)
Transports cholesterol from liver to cells in body
High Density Lipoprotein (HDL)
Removes excess cholesterol from cells and transports to liver
Know this chart

13. Utilization of Lipids
The liver uses fatty acids to synthesize a variety of lipids
Chem Figures From:
Linoleic (Ω 6)
Essential fatty acids are used for: 1) synthesis of membrane components 2) synthesis of eicosanoids
Linolenic acid, EPA, and DHA (Ω 3)
Figure From: Hole’s Human A&P, McGraw Hill, 2012

14. Metabolism and fate of macronutrients
Review
Metabolism and fate of macronutrients
Carbohydrate
Broken down into monosaccharides
Metabolism, glycogen, fat, pentose sugars
Lipids
Saturated vs. unsaturated fats
Broken down into glycerol and fatty acids
Used for energy (or storage of energy)
Proteins
Complete vs. incomplete proteins
Broken down into amino acids
Structural components or energy