Gastrointestinal System

Question 1

what are the types of digestion

Answer 1

mechanical and chemical

Question 2

what are the stages of nutrient intake

Answer 2

digestion (mechanical and chemical), absorption

Question 3

what are two factors that can help with digestion and absorption

Answer 3

motility and secretion

Question 4

label the organs of the GI system

Answer 4

main points: mouth, pharynx, esophagus, stomach, small and large intestine, rectum, anus

Question 5

label the accessory glands of the GI system

Answer 5

main points: liver, salivary glands, gallbladder, pancreas

Question 6

what are the main layers of the GI tract wall

Answer 6

mucosa, submucosa, muscularis externa, serosa

Question 7

draw a diagram of the GI tract wall with the main parts

Answer 7

….

Question 8

what are the functions of the mouth

Answer 8

• chewing
• lubrication and breakdown of food with saliva
• (tongue) manipulation of food

Question 9

describe the stomach and its function

Answer 9

• swelling of esophagus
• has gastric pits with secretory cells
• acidic
• chemical and mechanical digestion (chyme)

Question 10

what are the secretory cells of stomach gastric pits

Answer 10

neck, chief, parietal, G-cells

Question 11

what is the stomach lining protected by

Answer 11

gastric mucosal barrier

Question 12

draw a diagram showing the anatomy of the stomach

Answer 12

….

Question 13

what are neck cells responsible for

Answer 13

secretion of mucus

Question 14

what are chief cells responsible for

Answer 14

secretion of pepsinogen

Question 15

what are parietal cells responsible for

Answer 15

secretion of acid

Question 16

what are the divisions of the small intestine (start to end)

Answer 16

duodenum, jejunum, ileum

Question 17

what is the purpose of the ascending, descending, transverse colon

Answer 17

absorption of water and ions from chyme

Question 18

what is the purpose of the sigmoid colon

Answer 18

storage

Question 19

what are the divisions of the colon

Answer 19

ascending, transverse, descending, and sigmoid

Question 20

antibiotics are a type of medicine that can kill harmful bacteria from infections; however, it can also kill good bacteria that is present in the body. how will this affect the body and how can this bacteria be re-accounted for?

Answer 20

• microbiome important for digesting fibre, and producing vitamin K (blood clotting; form and maintain bone structure) and B7 (body system support –> hair, skin, eyes, liver, nervous system)
• taking probiotics (yogurt, kombucha, kefir)

Question 21

describe carbohydrate digestion

Answer 21

• salivary and pancreatic amylase limitedly break down polysaccharides
• resulting products are digested by brush border enzymes in small intestine
• only monosaccharides are absorbed by body

Question 22

why are amylases limited in their ability to digest polysaccharides

Answer 22

amylases can’t break polysaccharide bonds at branch points (limit dextrins) or between glucose monomers at the very end of the chain (disaccharides)

Question 23

what are the brush border enzymes

Answer 23

• dextrinase
• glucoamylase
• sucrase
• lactase
• maltase

Question 24

what does dextrinase breakdown, and what is the resulting product

Answer 24

limit dextrins → glucose

Question 25

what does glucoamylase breakdown, and what is the resulting product

Answer 25

polysaccharides → glucose

Question 26

what does sucrase breakdown, and what is the resulting product

Answer 26

sucrose → fructose + glucose

Question 27

what does lactase breakdown, and what is the resulting product

Answer 27

lactose → galactose + glucose

Question 28

what does maltase breakdown, and what is the resulting product

Answer 28

maltose → 2 glucoses

Question 29

define absorption

Answer 29

transport of nutrients from lumen to blood

Question 30

what are the way(s) that glucose is absorbed by the body

Answer 30

- co-transport with sodium across apical membrane - facilitated diffusion across basolateral

Question 31

what are the way(s) that galactose is absorbed by the body

Answer 31

- co-transport with sodium across apical membrane - facilitated diffusion across basolateral membrane

Question 32

what are the way(s) that fructose is absorbed by the body

Answer 32

facilitated diffusion across both membranes

Question 33

draw a diagram of the brush border between the lumen and capillary that depicts how maltose is digested and absorbed

Answer 33

....

Question 34

what are the enzymes that digest proteins

Answer 34

endopeptidases and exopeptidases

Question 35

how do endopeptidases digest proteins

Answer 35

by splitting polypeptides at interior peptide bonds into small peptide fragments

Question 36

how do exopeptidases digest proteins

Answer 36

by cleaving amino acids from one end of the polypeptide

Question 37

describe protein digestion

Answer 37

- started by pepsin converted from pepsinogen and acidity in stomach - pancreatic proteases in small intestine, and brush border enzyme enterokinase complete protein digestion into amino acids, di, and tri peptides

Question 38

what is a zymogen

Answer 38

inactive form of a substance that converts into an enzyme when activated (by another enzyme)

Question 39

what does trypsinogen convert into when active and how

Answer 39

- trypsin - enterokinase

Question 40

what does chymotrypsinogen convert into and how

Answer 40

- chymotrypsin - trypsin

Question 41

what does procoarboxypeptidase convert into and how

Answer 41

- carboxypeptidase - trypsin

Question 42

draw out how small peptides and amino acids are able to absorb thru the apical membrane/basolateral membrane

Answer 42

....

Question 43

why is it more difficult to digest and absorb lipids

Answer 43

- non-water soluble - don't mix with stomach or intestinal contents - make fat large droplets

Question 44

what enzymes are able to digest lipids in small intestine

Answer 44

ligual lipase, gastric lipase, pancreatic lipase

Question 45

describe ligual lipase

Answer 45

lipase enzyme in saliva and remains active in stomach

Question 46

describe gastric lipase

Answer 46

lipase enzyme secreted into the gastric lumen

Question 47

describe pancreatic lipase

Answer 47

lipase enzyme that mixes with chyme in small intestine

Question 48

how are bile salts able to help with lipid droplet digestion

Answer 48

- surface area increases due to emulsification which helps more lipid to expose to water - exposure to water on edges makes a polar coating that helps lipid to mix better in water

Question 49

describe bile salts

Answer 49

- amphipathic molecule w hydrophilic polar groups on one side of molecule and other side is hydrophobic - synthesized in liver from cholesterol - secreted in bile to duodenum

Question 50

draw out how pancreatic lipase works to free fatty acids and monoglycerides from fat droplets

Answer 50

....

Question 51

how do free fatty acids and monoglycerides absorb into the body

Answer 51

thru simple diffusion into intestinal cells

Question 52

how are bile salts recycled

Answer 52

by liver using enterohepatic circulation

Question 53

water absorption is considered a(n) ____________ process

Answer 53

passive

Question 54

how do free fatty acids enter circulation

Answer 54

- enter smooth ER first and re-form into triglycerides and other lipids - lipids enter Golgi and become chylomicrons (enterocyte that made triglyceride-rich lipoprotein) - chylomicrons secreted by exocytosis from basolateral membrane into interstitial fluid - chylomicrons enter lymphatic system thru lacteal and eventually enter circulation

Question 55

why do fat droplets shrink as they move thru intestine

Answer 55

by action of pancreatic lipase