Hormones of GI Tract (Quiz) Flashcards

1
Q

which type of glands release their contents onto an epithelial surface directly or via a duct

A
  • exocrine
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2
Q

which glands have lost contact with the epithelial cell surface completely and release secretions into the blood stream

A
  • endocrine
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3
Q

what is the largest endocrine organ in the body based on surface area

A
  • GI tract
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4
Q

regulation of GI secretions through three mechanisms

A
  • direct stimulation when food enters GI tract
  • autonomic stimulation from sympathetic or parasympathetic system
  • influence of hormones in the blood
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5
Q

exocrine secretions of the salivary glands

A
  • salivary amylase

- lingual lipase

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6
Q

the three glands that produce saliva

A
  • sublingual
  • submandibular
  • parotid
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7
Q

saliva production controlled by ______ nervous system

A
  • autonomic (both sympathetic and parasympathetic)
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8
Q

parotid glands secrete more ______ saliva and the sublingual glands secrete more ________ saliva

A
  • parotid - serous

- sublingual - mucinous

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9
Q

components of saliva

A
  • mucous
  • lysozyme
  • lactoferrin
  • secretory IgA
  • amylase
  • lingual lipase
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10
Q

function of mucous

A
  • lubricates oral cavity and food
  • buffer for acid in stomach
  • forms protective film on teeth
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11
Q

function of lysozyme

A
  • attacks bacterial cell walls
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12
Q

function of lactoferrin

A
  • chelates iron and prevents growth of organisms that use iron for growth
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13
Q

function of secretory IgA

A
  • immune active against bacteria and viruses
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14
Q

function of salivary amylase

A
  • initial breakdown of starch in mouth and first part of stomach
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15
Q

how can salivary amylase survive a bit in the stomach

A
  • saliva provides some buffer with bicarb
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16
Q

function of lingual lipase

A
  • fat digestion
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17
Q

function of parietal cells

A
  • secrete acid and intrinsic factor
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18
Q

function of intrinsic factor

A
  • required for vitamin B12 absorption
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19
Q

where are parietal cells located

A
  • in body and fundus of stomach
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20
Q

location of enterochromaffin-like cells

A
  • middle of gastric pits
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21
Q

function of enterochromaffin-like cells

A
  • histamine secretion which leads to acid stimulation
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22
Q

location of chief cells

A
  • deep in gastric pits
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23
Q

function of chief cells

A
  • secrete pepsinogen which is converted to pepsin and starts protein breakdown
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24
Q

location of G and D cells

A
  • pylorus and antrum
25
Q

function of G cells

A
  • secrete gastrin for acid production

gastrin acts on parietal cells

26
Q

function of D cells

where are D cells located

A
  • secrete somatostatin to inhibit gastrin and acid production
  • stomach, intestine and pancreas
27
Q

what is the pH of the stomach in the interdigestive phase

why

A
  • low

- large amount of acid

28
Q

result of low pH in interdigestive phase

A
  • stimulates release of somatostatin from D cells
  • suppression gastrin release from G cells
  • decreases acid production
29
Q

what happens when food in introduced to the stomach

A
  • buffers in food raise intragastric pH

- food directly leads to stimulation of the vagus nerve

30
Q

what happens when food directly raises the intragastric pH

A
  • decrease stimulation of D cells
  • inhibits release of somatostatin
  • increases gastrin production and acid secretion
31
Q

what happens when food directly leads to stimulation fo the vagus nerve

A
  • secretes gastrin releasing peptide
  • GRP stimulates G cells to release gastrin into the blood stream
  • gastrin stimulates enterochromaffin-like cells, parietal cells, and chief cells to induce acid and pepsinogen secretion
32
Q

what is the neurotransmitter that stimulates G-cells

A
  • GRP NOT ACETYLCHOLINE
33
Q

what is cholecystokinin secreted by

A
  • I cells in duodenum and jejunum
34
Q

three functions of CCK

A
  • gallbladder contraction
  • stimulation of pancreatic enzymes
  • relaxation of sphincter of Oddi so pancreatic enzymes and bile can digest food
35
Q

CCK production is stimulated by

what kind of feedback loop is this

A
  • broken down food products like peptides and fatty acid chains
  • positive feedback loop
36
Q

when is CCK production terminated

A
  • when food moves to lower portions of the GI tract
37
Q

what is secretin made by

A
  • S cells deep in the duodenum
38
Q

function of secretin

A
  • stimulates bicarb secretion by the pancreas
  • increases action of CCK in producing pancreatic enzymes
  • decreases gastric acid secretion
39
Q

secretin stimulated by

A
  • protein digestion and acid
40
Q

negative feedback loop of secretin

A
  • stimulates bicarb rich secretions which buffers out the acidic food
  • decreases secretin production
41
Q

what do acinar cells contain

A
  • digestive enzyme
42
Q

function of centroacinar or ductal cells

A
  • secrete bicarbonate

- help deliver pancreatic enzymes into duodenum

43
Q

process of an acinar cells in the pancreas secreting an enzyme

A
  • CCK and Ach stimulate receptors to release digestive enzymes
  • movement of chloride across membrane along with passive transport of sodium
  • water follows eventually
44
Q

prime hormone to help with bicarb secretion in the centroacinar/duct cells in the pancreas

A
  • secretin
45
Q

process of centroacinar/duct cells in pancreas

A
  • secretin activates cAMP
  • cAMP activates CFTR chloride channel to pump chloride ions into duct lumen
  • chloride exchanged for bicarb
  • sodium and water follow to increase amount of fluid created
46
Q

prime inhibitor of centroacinar/duct process

A
  • somatostatin
47
Q

vasoactive intestinal peptide (VIP) is made by the

A
  • enteric nervous system
48
Q

function of vasoactive intestinal peptide (VIP)

A
  • stimulate intestinal secretion of electrolytes and water
  • inhibits gastric acid secretion
  • stimulates nitric oxide formation to relax sphincter
49
Q

vasoactive intestinal peptide (VIP) stimulated by

A
  • local distention

- vagal stimulation

50
Q

motilin secreted by

A
  • enterochromaffin likes and Mo cells in the stomach, small intestine, and colon
51
Q

function of motilin

A
  • produce migrating motor complexes
52
Q

gastric inhibitory polypeptide (GIP) secreted by

A
  • K cells in duodenum
53
Q

functions of gastric inhibitory polypeptide (GIP)

A
  • decrease gastric acid secretion
  • increase insulin release
  • slows gastric emptying
54
Q

gastric inhibitory polypeptide (GIP) also known as

A
  • glucose-dependent insulinotropic peptide
55
Q

gastric inhibitory polypeptide (GIP) simulated by

A
  • glucose

- fatty acids

56
Q

alpha cells of pancreas secrete ________ which _______ serum glucose

A
  • glucagon

- increases

57
Q

beta cells of pancreas secrete ______ which ______ serum glucose

A
  • insulin

- decrease serum glucose

58
Q

function of somatostatin

A
  • inhibits secretion of hormones

- decrease rate of gastric emptying and reduces smooth muscle contractions in intestine

59
Q

somatostatin stimulated by

A
  • acid in the lumen