Chapter 3

Question 1

Digestion

Answer 1

process of breaking food into components small enough to be absorbed by the body

Question 2

Absorption

Answer 2

process of taking substances into the interior of the body

Question 3

Gastrointestinal (GI) tract

Answer 3

hollow tube consisting of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus

Question 4

Watery diarrhea means

Answer 4

you’re not absorbing nutrients

Question 5

Transit time

Answer 5

amount of time it takes food to pass the length of the GI tract

i. Varies upon what you eat

Question 6

Feces

Answer 6

body waste, including unabsorbed food residue, bacteria, and dead cells

Question 7

a. Enzymes

Answer 7

proteins that speed up chemical rxns;

remain unchanged

Question 8

i. Hormones

Answer 8

ii. Made some place specific & they travel by blood

specific synthesis site; travel by blood to their target organ; action at receptors (proteins) on cell membrane

Question 9

What is direction (in terms of organs) of digestion?

Answer 9

Brain –> mouth –> stomach –> gallbladder, liver, and pancreas –> small intestine –> large intestine –> anus

Question 10

digestion and the brain

Answer 10

Digestion starts in brain w/ sense of smell and sight

Question 11

Mouth

Answer 11

> entry point for food into the digestive tract
saliva
chewing

Question 12

Importance of saliva

Answer 12

Saliva contains:
Salivary amylase: starts to break down carbs
Lysozymes: inhibit bacterial growth in mouth

Question 13

Importance of chewing

Answer 13

Chewing: Mechanically breaks food down
The smaller, the easier to digest
Increases surface area for contact w/ digestive enzymes

Question 14

Stomach

Answer 14

holding and mixing tank (2 to 4 hours)

1. Hydrochloric acid (HCL) to digest food , make certain minerals easier to absorb
2. Hormones (inactive → active)
3. “Chyme” (the partially digested food)

Question 15

Small intestine

Answer 15

95% of digestion and absorption

Question 16

Gallbladder

Answer 16

stores bile (produced by liver)

Question 17

a. Bile

Answer 17

emulsifies fat (makes absorption easier)

Question 18

liver

Answer 18

produces bile

Question 19

2. Pancreas

Answer 19

secretes

a. Digestive enzymes
b. Bicarbonate ions – raises pH from stomach HCL

Question 20

In what form do we absorb carbs?

Answer 20

single sugar units

Question 21

In what form do we absorb proteins?

Answer 21

amino acids

Question 22

In what form do we absorb lipids?

Answer 22

Triglycerides: made up of fatty acids

[No cals in cholesterol, only in triglycerides]

Question 23

What is the system of transport of WATER-soluble nutrients?

Answer 23

portal system: goes from intestinal tract to liver

Question 24

What is the system of transport of FAT-soluble nutrients?

Answer 24

lymph: bypasses liver, can be deposited directly into blood

Question 25

3 types of absorption

Answer 25

Passive, facilitative, active

Question 26

Passive Abspt

Answer 26

no carrier, no energy (ATP) needed

i. Need: concentration gradient
ii. Water, some fats, some minerals

Question 27

Facilitative Abspt

Answer 27

carrier, no energy needed

i. Need: concentration gradient
ii. Fructose

Question 28

Active Abspt

Answer 28

carrier, energy needed

i. Carbohydrate, amino acids

Question 29

Large Intestine

Answer 29

> Comprises the colon & the rectum
Can absorb: water, some vitamins & minerals
Intestinal microflora are produced here
Water, nutrients, and fecal material may spend up to 24hrs in large intestine

Question 30

III. Probiotics – live bacteria; health benefits?

Answer 30

> Unclear whether adding in probiotics has any health benefits
NATURAL food sources like plain yogurt and other fermented products have live bacteria – is beneficial

Question 31

IV. Prebiotics

Answer 31

> Not digested by small intestines
In colon: can stimulate growth/activity of certain types of bacteria
Food sources: onions, garlic, bananas, artichokes, raw oats, unrefined flour & barley

Question 32

GI Tract’s Role in Immune Fxn

Answer 32

> GI tract plays big role in protecting body from infection

>Limits abpt of toxins & disease-causing organisms

Question 33

What are food allergies and common food allergens?

Answer 33

Food allergies: absorbing protein whole

>Wheat, shellfish and fish, nuts, milk, eggs

Question 34

1. Enteral nutrition

Answer 34

tube feeding

Question 35

2. TPN: total parenteral nutrition

Answer 35

fed directly to a vein, but high risk of infection, gut starts to atrophy overtime

Question 36

d. Catabolic pathways

Answer 36

release energy (trapped in chemical bonds); breaking down
energy trapped at ATP

Question 37

e. Anabolic

Answer 37

use energy to synthesize products

Question 38

VIII. Adenosine Triphosphate (ATP)

Answer 38

a. Food energy

b. Break of phosphate group high-energy bonds

Question 39

IX. Carbohydrate metabolism

Answer 39

a. Glycolysis – Glucose (6 carbon) catabolized to pyruvate (3 carbon)
1. Pyruvate → acetic acid (2 carbon)

Question 40

b. Sources of glucose for glycolysis

Answer 40

i.Glycogen – stored carbs on liver and in mscls
>Mscl glycogen are ONLY used to fuel working mscl
ii.Gluconeogenesis – use amino acids to create glucose

Question 41

X. Lipid metabolism

Answer 41

> Metabolism of triglycerides (TG)
Lipolysis (occurs in adipose/fat tissue itself)
>TG → free fatty acid (FFA) (and glycerol)
Beta oxidation – catabolism of FFA
>End with acetic acid (2 carbon)

Question 42

XII. Fate of acetic acids

Answer 42

> Enters Citric acid cycle (AKA Krebs cycle, TCA cycle)
>2 carbon acetic acid enters → end w/ CO2, electrons
Electron transport chain – where most of ATP is generated
>Final pathways for ATP prodxn
>[See figure in book]