Nutrition Chapter 4 Flashcards Preview

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Flashcards in Nutrition Chapter 4 Deck (36):
1

What are the steps of the GI tract flow?

1. mouth and salivary glands
2. esophogas
3. stomach
4. pancreas
5. liver
6. gallbladder
7. small intestine
8. large intestine
9. rectum
10. anus

2

What role does the mouth and salivary glands play in digestion?

chew food, perceive taste, moisten food
lubricate food with mucus
release amylase enzyme (starch digesting)
initiate swallowing reflex

3

What role does the esophagus play in digestion?

lubricate with mucus
move food to stomach (peristaltic waves)

4

What role does the stomach play in digestion?

store, mix, dissolve and continue digestion
dissolve particles with secretions
kill microorganisms with acid
release protein-digesting enzyme (pepsin)
lubricate and protect stomach surface
regulate emptying into small intestine
produce intrinsic factor of B-12 absorption

5

What role does the pancreas play in digestion?

secrete sodium bicarbonate and enzymes for digesting CHO, PRO, and FAT

6

What role does the liver play in digestion?

produce bile to aid fat digestion and absorption

7

What role does the gallbladder play in digestion?

store, concentrate, and later release bile into the small intestine

8

What role does the small intestine play in digestion?

mix and propel contents
lubricate
digest and absorb most substances

9

What role does the large intestine play in digestion?

mix and propel contents
absorb Na, K and H2O
house bacteria
lubricate
synthesize some vitamins and short-chain fatty acids
form feces

10

What role does the rectum play in digestion?

hold feces and expel via the anus

11

What are the 4 layers of the wall of the alimentary canal?

1. mucosa - innermost layer, not smooth, has lumen
2. submucosa - blood vessels that carry substances
3. muscle - move food
4. serosa - outermost layer, protects the GI tract

12

What is amylase?

A digestive enzyme that breaks down starch into simple sugars.

13

What is lipase?

A digestive enzyme that breaks down fat.

14

What is gastrin?

A hormone that controls the release of HCl and pepsinogen.

15

What are the accessory organs?

salivary glands, liver, bile duct, gallbladder, pancreatic duct, pancreas

16

Where does most digestion occur?

upper part of the small intestine (duodenum)

17

What are the types of mechanical breakdown?

mastication (mouth)
peristalsis (esophagus)
segmentation (small intestine)
mass movement (large intestine)
sphincters
crushing into liquid (stomach)

18

What are the types of chemical breakdown?

digestive enzymes, saliva, gastric juice, pancreatic secretions, bile, intestinal flora

19

What is saliva?

comes from the salivary glands
lubricates and breaks down CHO (and FAT in infants)

20

What are the gastric juices?

occur in the stomach
HCl, mucus, pepsinogen, intrinsic factor

21

What are the functions of the gastric juices?

partially digests protein
destroys salivary amalyase
converts pepsinogen to pepsin
assists in calcium absorption
destroys bacteria

22

What are the pancreatic secretions?

sodium bicarbonate (neutralizes stomach acid)
enzymes (proteases, lipases, carbohydrases)

23

What is bile?

made in the liver, stored in the gallbladder, released in the small intestine
emulsifies fat
*recycled (enterohepatic circulation)

24

What is intestinal flora?

occurs in the colon
produces vitamins (K and biotin), metabolizes fiber, produces SCFAs, maintains a healthy colon, prevents colonization of harmful bacteria

25

Where does most absorption occur?

in the small intestine

26

What are the 4 types of absorption?

passive diffusion
facilitated diffusion
active diffusion/transport
endocytosis

27

What is the fate of the absorbed nutrients?

They enter either the vascular system or the lymphatic system and are eventually brought to the liver where they are packaged and distributed to cells.

28

Vascular system nutrients

water soluble and small particles
intestines --> portal vein --> liver

29

lymphatic system nutrients

fat soluble and large particles
intestines --> thoracic duct --> subclavian vein
enter the bloodstream

30

What are the hormones associated with digestion?

gastrin
CCK
secretin
gastric inhibitory peptide

31

What is gastrin?

stimulates the secretion of stomach acid and pepsinogen, stimulated by food entering the stomach or thoughts of food

32

What is CCK?

stimulates gallbladder to release bile, stimulates release of pancreatic enzymes, stimulated by food, presence of fat and protein in duodenum

33

What is secretin?

stimulates the pancreas to secrete bicarbonate, maintains proper pH in small intestine, stimulated by the presence of acidic chyme and peptones

34

What is gastric inhibitory peptide (GIP)?

inhibits secretion of stomach acid and enzymes, slows gastric emptying, stimulated by fat and protein in chyme

35

What are common digestive tract issues?

heartburn, GERD, ulcers, constipation, diverticular disease, diarrhea, vomiting, gas, IBS, IBD

36

What are digestive enzymes?

proteins that speed up chemical reactions, lower energy needed, act on a specific substrate and convert substrates into products