GI tract

Question 1

Somatostatin

Answer 1

secreted by D cells found in the duodenum and the pancreas (stimulated by bile acid secretion and decreased by the vagal nerve)

Question 2

A major producer of somatostatin

Answer 2

Pancreas

Question 3

Action of somatostatin

Answer 3

Controls acid/pepsinogen secretion through a negative feed back loop and inhibits the release of glucagon/insulin by the pancreas (also decreases gallbladder contraction)

Question 4

Pancreatic amylase

Answer 4

Breaks down carbohydrates into simple sugars

Question 5

Brush border enzymes

Answer 5

Assist in digestion and nutrient absorption

Question 6

Pancreas secretes

Answer 6

Bicarbonate (to neutralize stomach acid)

Question 7

Brush border activates

Answer 7

Pancreatic trypsin via enterokinase which activates the rest of the digestive enzymes

Question 8

Digestion primarily occurs in the….

Answer 8

duodenum

Question 9

Pancreatic lipase

Answer 9

Breaks down lipids

Question 10

Gallbladder releases…

Answer 10

Bile that has been synthesized in the liver. Bile is useful in emulsifying fats.

Question 11

Trypsin

Answer 11

activates chymotrypsin and other pancreatic enzymes

Question 12

Trypsin and chymotrypsin digest

Answer 12

proteins into amino acids

Question 13

Secretin

Answer 13

Released from S cells in the duodenum and is stimulated by fatty acid presence in the duodenum

Question 14

Secretin stimulates

Answer 14

bicarbonate secretions from ductal cells in the pancreas (buffers chyme) and bile acid secretions from the liver (helps emulsify fats for digestion). Also decreases gastric acid secretion from the stomach to prevent an excess of acid.

Question 15

Salivating amylase

Answer 15

breaks down carbs

Question 16

Lingual lipase

Answer 16

breaks down fats (triglycerides)

Question 17

Major site of alcohol absorption

Answer 17

Stomach

Question 18

Folate absorption occurs in

Answer 18

both duodenum and proximal jujenum (primary site)

Question 19

Bile reabsorption occurs in

Answer 19

terminal ileum

Question 20

B12 (cobalamin) is absorbed in the

Answer 20

terminal ileum

Question 21

Iron is primarily absorbed in the

Answer 21

duodenum

Question 22

Chief cells secrete

Answer 22

pepsinogen (inactive)

Question 23

Pepsinogen is activated by

Answer 23

H+ ions in the stomach

Question 24

Pepsin

Answer 24

breaks down proteins into small polypeptide chains

Question 25

Gastrin

Answer 25

is secreted by G cells and stimulates stomach into mixing its contents and also stimulates parietal cells to secrete HCl release (H+ ions)

Question 26

Parietal cells

Answer 26

secrete HCl and intrinsic factor which helps in Vitamin B12 absorption

Question 27

Mucous cells in the stomach

Answer 27

Release both mucous and bicarbonate to protect stomach lining

Question 28

Large lipids are transported to the liver through

Answer 28

the hepatic portal as chylomicrons

Question 29

Lacteals

Answer 29

transport chylomicrons through the lymphatic system

Question 30

Carbohydrates and .. are absorbed through

Answer 30

active transport in the duodenum

Question 31

The hepatic portal transports

Answer 31

nutrients to the liver for processing

Question 32

Most fats

Answer 32

bypass first-pass metabolism in the liver and go straight to circulation through the lymphatic system

Question 33

The colon is responsible for

Answer 33

electrolyte/water/bile reabsorption

Question 34

Na+/K+ are absorbed in

Answer 34

transverse colon

Question 35

I cells

Answer 35

release CCK in duodenum/jejunum which stimulates contraction of the gallbladder (release of bile)

Question 36

CCK

Answer 36

released by I cells in the presence of amino acids and fatty acids in the duodenum and stimulates the contraction of the gallbladder, induces relaxation of the sphincter of oddi, & decreases gastric acid emptying.

Question 37

chemical digestion that begins in the mouth involves

Answer 37

amylase (starch ---> maltose) and lysozyme (antibacterial)

Question 38

salivary glands

Answer 38

parietal, submandibular, sublingual made up of: serous/mucous cells intercalated ducts: may secrete lysozyme striated ducts: modify primary saliva with electrolytes

Question 39

saliva consist of

Answer 39

99.5% water, 0.5% electrolytes/proteins

Question 40

serous cells

Answer 40

contain zymogen granules that contain amylase and lysozyme (enzymes that are present at all times) which is secreted through exocytosis

Question 41

Initial salivary secretion are

Answer 41

isotonic with plasma

Question 42

Final salivary secretion is

Answer 42

hypotonic with plasma (NaCl is only 1/7th of plasma)

Question 43

Chief cells

Answer 43

are stimulated to secrete ACh and gastrin to produce pepsinogen for protein digestion

Question 44

Parietal cells

Answer 44

are stimulated to secrete ACh and gastrin to produce HCl and intrinsic factor

Question 45

Enterochromaffin cells (ECF)

Answer 45

stimulated by ACh and gastrin to release histamine which in turn stimulate parietal cells

Question 46

Cephalic phase

Answer 46

seeing, smelling, tasting, chewing, swallowing stimuli

Question 47

Pancreatic juice is

Answer 47

``` isotonic with extracellular fluid: NaCl @ low rates NaCl & HCO3- @ high rates K+ present at all rates Na & K concentrations are approx to plasma ```

Question 48

Bile salts are synthesized from

Answer 48

cholesterol in the liver by Cyp7A1

Question 49

cholangiocytes secrete

Answer 49

bicarb rich fluid under the regulation of secretin

Question 50

Secretin targets the CFTR

Answer 50

regulates the Cl-/HCO3 exchanger to work