Lecture #3: Digestive System

Question 1

How does the ancestral diet compare to a modern diet?

Answer 1

Ancestral diet had:
- less sugar
- more protein
- more natural food (less added preservatives)
- less salt
- more fiber

Question 2

Catabolism

Answer 2

Breakdown of structure by enzymatic hydrolysis
• enzymatic hydrolysis: enzymes and water

Question 3

Anabolism

Answer 3

Build up of structure

Question 4

Calorie containing molecular

Answer 4

Proteins, carbohydrates, lipids

Question 5

Proteins break down into?

Answer 5

Polypeptides, then animo acids

Question 6

Carbohydrates break down into?

Answer 6

Polysaccharides, then monosaccharides (ex: glucose, fructose)

Question 7

Lipids break down into?

Answer 7

Glycerol + 3 fatty acid chains

Question 8

What does saliva do?

Answer 8

1. Moistens food
2. Antimicrobials
3. Begin carb digestion
   - amylase = enzyme for breaking down starch

Question 9

What is the stomach and what does it do in the digestion process?

Answer 9

Acidic (PH (~ 2))
1. Begin protein breakdown
- Pepsin : enzyme for protein breakdown (works at a low ph)
• Cells store and release pepsinogen (less degrading)
• cells also release hydrochloric acid (HCl)
- turns pepsinogen into pepsin (active form of enzyme)
peptic ulcer - break in epithelial lining of stomach
• cause is bacteria infection
Acid reflux : Burning of lining of esophagus (heartburn)

Question 10

What is the small intestine and what does it do in the digestion process?

Answer 10

3 parts of small intestine:
- durdeum (start of small intestine, more breakdown here, less adsorption)
- jejunun (middle of small intestine)
- ileum (end of small intestine, less breakdown here, more adsorption)

Question 11

What is at the Junction of stomach + small intestine?

Answer 11

1. pyloric sphinctur - controls release of material into small intestine
2. Pancreas: produces bicarbonate to neutralize acid
   - PH ~7

Question 12

What is trypsin?

Answer 12

Trypsin is an enzyme that helps break down protein, works at a ph of ~ 7

Question 13

8 essential amino acids

Answer 13

• must be in diet
  
  • other 12 can be manufactured by body
  • no plant food has all 8
  • mix grain and legume (green peas, lentils, beans) and get all 3

Question 14

How is digestion finished?

Answer 14

More amylases are added such as lactase

Question 15

What is lactase?

Answer 15

Enzyme that breaks down lactose
- lactose = milk sugar
- produced in large quantities in juveniles (humans)

Question 16

What is emulsification?

Answer 16

Liver produces bile (contains bile salts)
• stored in gall bladder

Question 17

Bile salts

Answer 17

physical seperation of fat droplets

Question 18

Lipase

Answer 18

Enzyme that breaks down lipids

Question 19

Hepatic portal system

Answer 19

Small intestine —————-> Liver
Begins and ends at capillary system
- does not go through heart

Question 20

Small intestine — liver — heart —body

Answer 20

Capillary system
- detoxification
- removes sugar from blood and stores it as glycogen

Question 21

Large intestine

Answer 21

Absorb water + minerals as needed

Question 22

Feces

Answer 22

Undigested material + water + coliform bacteria (fiber)

Question 23

What does the large intestine do when you’re dehydrated?

Answer 23

large intestine will take water and circulate it back into the body

Question 24

What causes constipation?

Answer 24

Lack of fiber, water, and/or exercise

Question 25

What are vitamins?

Answer 25

organic molecules needed in small amounts
• not that many calories

Question 26

water soluble vitamins

Answer 26

Excess is excreted in urine
Ex: vitamin C
- advantage: can get rid of easily in urine
- disadvantage: need to consume daily

Question 27

Fat soluble vitamins

Answer 27

Excess is stored in fat
Ex: vitamin A
- advantage: not needed everyday, can be taken from body
- disadvantage: can store too much and build up to a toxic level (not likely)

Question 28

Minerals

Answer 28

Inorganic (no calories)
- ex: calcium

Question 29

Osteoporosis

Answer 29

weak bones due to lack of calcium and exercise (resistance exercise)
- women with lower levels of estrogen (after menopause) are more at risk

Question 30

Order of the parts for the passage of food

Answer 30

Mouth -> esophagus -> stomach -> sphincter -> small intestine-> large intestine

Question 31

what are the primary sections of the digestive system where the following nutrients are digested?

Answer 31

Lipids —> small intestine
Carbohydrates —> mouth (amalases)
Protein —> stomach (pepsin)