Hormones of GI Tract (Quiz) Flashcards
(59 cards)
1
Q
which type of glands release their contents onto an epithelial surface directly or via a duct
A
- exocrine
2
Q
which glands have lost contact with the epithelial cell surface completely and release secretions into the blood stream
A
- endocrine
3
Q
what is the largest endocrine organ in the body based on surface area
A
- GI tract
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
5
Q
exocrine secretions of the salivary glands
A
- salivary amylase
- lingual lipase
6
Q
the three glands that produce saliva
A
- sublingual
- submandibular
- parotid
7
Q
saliva production controlled by ______ nervous system
A
- autonomic (both sympathetic and parasympathetic)
8
Q
parotid glands secrete more ______ saliva and the sublingual glands secrete more ________ saliva
A
- parotid - serous
- sublingual - mucinous
9
Q
components of saliva
A
- mucous
- lysozyme
- lactoferrin
- secretory IgA
- amylase
- lingual lipase
10
Q
function of mucous
A
- lubricates oral cavity and food
- buffer for acid in stomach
- forms protective film on teeth
11
Q
function of lysozyme
A
- attacks bacterial cell walls
12
Q
function of lactoferrin
A
- chelates iron and prevents growth of organisms that use iron for growth
13
Q
function of secretory IgA
A
- immune active against bacteria and viruses
14
Q
function of salivary amylase
A
- initial breakdown of starch in mouth and first part of stomach
15
Q
how can salivary amylase survive a bit in the stomach
A
- saliva provides some buffer with bicarb
16
Q
function of lingual lipase
A
- fat digestion
17
Q
function of parietal cells
A
- secrete acid and intrinsic factor
18
Q
function of intrinsic factor
A
- required for vitamin B12 absorption
19
Q
where are parietal cells located
A
- in body and fundus of stomach
20
Q
location of enterochromaffin-like cells
A
- middle of gastric pits
21
Q
function of enterochromaffin-like cells
A
- histamine secretion which leads to acid stimulation
22
Q
location of chief cells
A
- deep in gastric pits
23
Q
function of chief cells
A
- secrete pepsinogen which is converted to pepsin and starts protein breakdown
24
Q
location of G and D cells
A
- pylorus and antrum
25
function of G cells
- secrete gastrin for acid production
gastrin acts on parietal cells
26
function of D cells
where are D cells located
- secrete somatostatin to inhibit gastrin and acid production
- stomach, intestine and pancreas
27
what is the pH of the stomach in the interdigestive phase
why
- low
| - large amount of acid
28
result of low pH in interdigestive phase
- stimulates release of somatostatin from D cells
- suppression gastrin release from G cells
- decreases acid production
29
what happens when food in introduced to the stomach
- buffers in food raise intragastric pH
| - food directly leads to stimulation of the vagus nerve
30
what happens when food directly raises the intragastric pH
- decrease stimulation of D cells
- inhibits release of somatostatin
- increases gastrin production and acid secretion
31
what happens when food directly leads to stimulation fo the vagus nerve
- 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
what is the neurotransmitter that stimulates G-cells
- GRP NOT ACETYLCHOLINE
33
what is cholecystokinin secreted by
- I cells in duodenum and jejunum
34
three functions of CCK
- gallbladder contraction
- stimulation of pancreatic enzymes
- relaxation of sphincter of Oddi so pancreatic enzymes and bile can digest food
35
CCK production is stimulated by
what kind of feedback loop is this
- broken down food products like peptides and fatty acid chains
- positive feedback loop
36
when is CCK production terminated
- when food moves to lower portions of the GI tract
37
what is secretin made by
- S cells deep in the duodenum
38
function of secretin
- stimulates bicarb secretion by the pancreas
- increases action of CCK in producing pancreatic enzymes
- decreases gastric acid secretion
39
secretin stimulated by
- protein digestion and acid
40
negative feedback loop of secretin
- stimulates bicarb rich secretions which buffers out the acidic food
- decreases secretin production
41
what do acinar cells contain
- digestive enzyme
42
function of centroacinar or ductal cells
- secrete bicarbonate
| - help deliver pancreatic enzymes into duodenum
43
process of an acinar cells in the pancreas secreting an enzyme
- CCK and Ach stimulate receptors to release digestive enzymes
- movement of chloride across membrane along with passive transport of sodium
- water follows eventually
44
prime hormone to help with bicarb secretion in the centroacinar/duct cells in the pancreas
- secretin
45
process of centroacinar/duct cells in pancreas
- 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
prime inhibitor of centroacinar/duct process
- somatostatin
47
vasoactive intestinal peptide (VIP) is made by the
- enteric nervous system
48
function of vasoactive intestinal peptide (VIP)
- stimulate intestinal secretion of electrolytes and water
- inhibits gastric acid secretion
- stimulates nitric oxide formation to relax sphincter
49
vasoactive intestinal peptide (VIP) stimulated by
- local distention
| - vagal stimulation
50
motilin secreted by
- enterochromaffin likes and Mo cells in the stomach, small intestine, and colon
51
function of motilin
- produce migrating motor complexes
52
gastric inhibitory polypeptide (GIP) secreted by
- K cells in duodenum
53
functions of gastric inhibitory polypeptide (GIP)
- decrease gastric acid secretion
- increase insulin release
- slows gastric emptying
54
gastric inhibitory polypeptide (GIP) also known as
- glucose-dependent insulinotropic peptide
55
gastric inhibitory polypeptide (GIP) simulated by
- glucose
| - fatty acids
56
alpha cells of pancreas secrete ________ which _______ serum glucose
- glucagon
| - increases
57
beta cells of pancreas secrete ______ which ______ serum glucose
- insulin
| - decrease serum glucose
58
function of somatostatin
- inhibits secretion of hormones
| - decrease rate of gastric emptying and reduces smooth muscle contractions in intestine
59
somatostatin stimulated by
- acid in the lumen
