Digestion, absorption and sources of energy

Question 1

Review: What is Digestion

Answer 1

• Mechanical
• Chemical

Question 2

GI tract review

Answer 2

mouth -> pharynx -> epiglottis -> esophagus -> esophageal sphincter -> stomach -> pyloric sphincter -> gallbladder -> pancreas -> duodenum -> jejunum -> ileum -> ileocecal valve -> colon -> appendix -> rectum -> anus

Question 3

Mouth

Answer 3

• Saliva lubricates
• Amylase starts starch digestion
• Chewing breaks down food

Question 4

Pharynx

Answer 4

Epiglottis keeps food from airway

Question 5

Esophagus

Answer 5

Peristalsis starts

Question 6

Stomach

Answer 6

• Food storage
• Acid kills bacteria, unfolds proteins, activates pepsin (breaks down protein)

Question 7

Small intestines

Answer 7

• Most digestion & absorption
• Pancreatic enzymes digest food & bicarbonate neutralizes acid
• Bile breaks fat

Question 8

Large Intestine

Answer 8

• absorb water
• bacteria digest fiber, make vitamins

Question 9

Involuntary Muscles and Glands

Answer 9

Gastrointestinal motility (peristalsis, segmentation)
Liquefying process: chyme
(chewing, saliva)
Stomach muscles with the help of the pyloric sphincter

Question 10

What is absorption?

Answer 10

• The small intestine:
  where most of the absorption takes place
  villi and microvilli
  specialization in the intestinal tract

Question 11

where do the nutrients go?

Answer 11

• Lymphatic system - most lipid-soluble nutrients
• bloodstream - through the liver by way of the hepatic portal vein
• circulatory route of blood (in relation to nutrient absorption) is Heart to artiest to capillaries (in intestines) to hepatic portal vein to liver to hepatic vein to heart

Question 12

Carbohydrates

Answer 12

• include sugars, starch, fiber
• energy nutrients compose of monosaccharides
• carbo = carbon
• hydrate = water
  Carbohydrates are the bodies PREFERRED energy source (CHO)

Question 13

Types of Carbohydrates

Answer 13

1. Simple
2. Complex

Question 14

Simple Carbs

Answer 14

monosaccharides
disaccharides

Question 15

Complex Carbs

Answer 15

polysaccharides

Question 16

Examples of monosaccharides

Answer 16

• glucose
• fructose
• galactose

Question 17

Examples of disaccharides

Answer 17

• maltose (glucose + glucose)
• sucrose (glucose + fructose)
• lactose (glucose + galactose)

Question 18

Examples of polysaccharides

Answer 18

• Fibre (soluble
• Starches
• Glycogen (storage form in animals/humans. Not dietary)

Question 19

Saccharide =

Answer 19

sugar molecule

Question 20

Lactose Intolerance

Answer 20

Lactose -> broken down by lactase to galactose + glucose
- babies born with lactase
- decreases with age (some people faster than others)
- If lactose continues through GI undigested (draws in water, creates gas in colon, explosive diarrhea)

Question 21

Complex Carb: Oligosaccharides

Answer 21

3-10 monosaccharides

Question 22

Complex Carbs: Polysaccharides

Answer 22

large molecules composed on chains of hundreds or even thousands of monosaccharides
- starch
- fibre
- glycogen

Question 23

Glycogen - CHO storage in animals/mammals

Answer 23

• The body breaks off a chain when it needs energy
• Made and stored in the liver
• Found in our muscle & liver (not in foods - meat to a limited extent)
• Role in blood glucose regulation (ie. low blood sugar stimulates the release of glucagon which breaks down the glycogen to form glucose - the body and brain want glucose

Question 24

Starch - CHO storage in plants

Answer 24

A plant polysaccharide composed of glucose and digestible by human beings
- Food sources: (grain products, legumes, starchy vegetables)

Question 25

Fiber - CHO not well digested

Answer 25

- complex, not completely broken down to be used as energy - polysaccharide but with bonds that human enzymes can't break - can be 2kcal/g when fermentation present - found in plant-based foods - Examples: cellulose, pectins, gums, mucilages, non-polysaccharide lignins

Question 26

Insoluble Fiber

Answer 26

Doesnt dissolve in water. Passes unchanged through colon -Normalize bowel movements/increase regularity (Roughage, bulk fiber)

Question 27

Soluble Fiber

Answer 27

Dissolves in water. Gels like pectin/gelatin 1. holds water in stool 2. Binds cholesterol and simple sugars 3. Delays transit time (sponge)

Question 28

AI for fiber

Answer 28

38g/day for men 25 g/day for women Concern that Canadians are not meeting their fibre requirements

Question 29

Harmful effects of excessive fiber

Answer 29

- mineral balance - nutrient displacement - energy requirements - Increased fluid needs -Increased fluid needs whenever a laxative is given or fiber intake is increased -Energy requirements – fiber doesn’t supply energy -Nutrient displacement

Question 30

Insulin

Answer 30

pancreatic hormone that regulates blood glucose levels

Question 31

Glucagon

Answer 31

pancreatic hormone that releases glycogen from liver

Question 32

Somatostatin

Answer 32

hormone produced by pancreas & hypothalamus that inhibits insulin and glucagon

Question 33

Glycemic Index

Answer 33

a method of classifying foods according to their potential for raising blood glucose

Question 34

Glycemic response

Answer 34

the extent to which a food raises the blood glucose concentration and elicits an insulin response

Question 35

Glycogenolysis

Answer 35

process converting glycogen back to glucose

Question 36

Gluconeogenesis

Answer 36

process producing glucose from fat & protein (not very efficient for fat)

Question 37

Sugar alcohols are carbohydrates and have the same energy as sugar

Answer 37

False

Question 38

Sugar alcohols occur naturally in fruit and veggies

Answer 38

True

Question 39

Sugar alcohols have very little, if no, known side effects

Answer 39

False

Question 40

Examples of sugar alcohol are erythritol, mannitol, and xylitol

Answer 40

True

Question 41

A common non-nutritive sweetener is aspartame?

Answer 41

True

Question 42

Studies indicate that aspartame may cause bladder tumours in lab animals

Answer 42

False

Question 43

Sugar alcohols and non-nutritive sweeteners DO contribute to dental caries

Answer 43

False

Question 44

Non-nutritive sweeteners contain no calories

Answer 44

True

Question 45

Examples of non-nutritive sweeteners are: stevia, saccharin, aspartame, and sucralose

Answer 45

True

Question 46

Using sugar alternatives can help people loose excess weight

Answer 46

False