Nutrition Chapter 4

Question 1

What are the steps of the GI tract flow?

Answer 1

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

Question 2

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

Answer 2

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

Question 3

What role does the esophagus play in digestion?

Answer 3

lubricate with mucus

move food to stomach (peristaltic waves)

Question 4

What role does the stomach play in digestion?

Answer 4

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

Question 5

What role does the pancreas play in digestion?

Answer 5

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

Question 6

What role does the liver play in digestion?

Answer 6

produce bile to aid fat digestion and absorption

Question 7

What role does the gallbladder play in digestion?

Answer 7

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

Question 8

What role does the small intestine play in digestion?

Answer 8

mix and propel contents
lubricate
digest and absorb most substances

Question 9

What role does the large intestine play in digestion?

Answer 9

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

Question 10

What role does the rectum play in digestion?

Answer 10

hold feces and expel via the anus

Question 11

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

Answer 11

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

Question 12

What is amylase?

Answer 12

A digestive enzyme that breaks down starch into simple sugars.

Question 13

What is lipase?

Answer 13

A digestive enzyme that breaks down fat.

Question 14

What is gastrin?

Answer 14

A hormone that controls the release of HCl and pepsinogen.

Question 15

What are the accessory organs?

Answer 15

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

Question 16

Where does most digestion occur?

Answer 16

upper part of the small intestine (duodenum)

Question 17

What are the types of mechanical breakdown?

Answer 17

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

Question 18

What are the types of chemical breakdown?

Answer 18

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

Question 19

What is saliva?

Answer 19

comes from the salivary glands

lubricates and breaks down CHO (and FAT in infants)

Question 20

What are the gastric juices?

Answer 20

occur in the stomach

HCl, mucus, pepsinogen, intrinsic factor

Question 21

What are the functions of the gastric juices?

Answer 21

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

Question 22

What are the pancreatic secretions?

Answer 22

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

Question 23

What is bile?

Answer 23

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

Question 24

What is intestinal flora?

Answer 24

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

Question 25

Where does most absorption occur?

Answer 25

in the small intestine

Question 26

What are the 4 types of absorption?

Answer 26

passive diffusion
facilitated diffusion
active diffusion/transport
endocytosis

Question 27

What is the fate of the absorbed nutrients?

Answer 27

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.

Question 28

Vascular system nutrients

Answer 28

water soluble and small particles

intestines –> portal vein –> liver

Question 29

lymphatic system nutrients

Answer 29

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

Question 30

What are the hormones associated with digestion?

Answer 30

gastrin
CCK
secretin
gastric inhibitory peptide

Question 31

What is gastrin?

Answer 31

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

Question 32

What is CCK?

Answer 32

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

Question 33

What is secretin?

Answer 33

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

Question 34

What is gastric inhibitory peptide (GIP)?

Answer 34

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

Question 35

What are common digestive tract issues?

Answer 35

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

Question 36

What are digestive enzymes?

Answer 36

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