GIT physiology Flashcards

1
Q

what are migrating myoelectric complex stimulated by?
1. _____ (increase/decrease) in chyme pH
2. _____ (increase/decrease) in plasma [motilin]

A
  1. increase in chyme pH
  2. increase plasma [motilin]
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2
Q

what is migrating myoelectric complex replaced by when a meal enters the stomach?

A

segmenting/mixing contractions

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3
Q

what are the 3 phases of swallowing?

A
  1. buccal (voluntary)
  2. pharyngeal (involuntary)
  3. oesophageal (involuntary)
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4
Q

which part of the brain controls the buccal phase of swallowing?

A

cerebral cortex

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5
Q

which part of the brain controls the pharyngeal and oesophageal phases of swallowing?

A

medulla (brainstem)

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6
Q

what are the functions of migrating myoelectric complex?

A
  1. move undigested remains to large intestine
  2. prevent overgrowth of bacteria
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7
Q

what are the 3 extrinsic salivary glands?

A
  1. parotid gland (largest)
  2. submandibular gland
  3. sublingual gland (smallest)
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8
Q

what is the function of mucin in the saliva?

A

lubrication of food

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9
Q

what is the enzyme present in saliva for carbohydrate digestion?

A

amylase (ptyalin)

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10
Q

what is ptyalism?

A

excessive salivation

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11
Q

what is xerostomia?

A

dry mouth (insufficient salivation)

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12
Q

what is the function of pepsin?

A

initiate protein digestion in stomach

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13
Q

what is the function of intrinsic factor?

A

allows absorption of vitamin B12

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14
Q

what do parietal cells secrete?

A

HCl and intrinsic factor

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15
Q

what do chief cells secrete?

A

pepsinogen

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16
Q

what do enterochromaffin-like cells secrete?

17
Q

what do G cells secrete?

18
Q

what do D cells secrete?

A

somatostatin

19
Q

what are the 4 types of secretory cells in gastric glands?

A
  1. mucus cells
  2. parietal cells
  3. chief cells
  4. enteroendocrine cells
20
Q

why can’t unconjugated bilirubin be renally excreted?

A

it is not water soluble; fat soluble

21
Q

what is the function of bile salts?

A

emulsify fats in small intestine

22
Q

what is lecithin?

A

phospholipid that combines with bile salts to emulsify fats

23
Q

what do acinar cells of the pancreas secrete?

A

pancreatic enzymes (synthesised in zymogen granules)

24
Q

which enzyme initiates activation of pancreatic enzymes?

A

membrane-bound enterokinase

25
what enzyme converts trypsinogen to trypsin?
enterokinase
26
what hormone is released in response to fat and protein in the duodenum?
cholecystokinin
27
what do acinar cells secrete in response to increase cholecystokinin?
digestive pancreatic enzymes
28
what stimulates ductal cells of the pancreas to increase bicarbonate secretion?
increase secretin in response to acidic chyme
29
what type of jaundice would have normal urine and stool colour?
pre-hepatic jaundice
30
what type of jaundice presents with dark urine and pale stools?
cholestatic/post-hepatic jaundice
31
what type of jaundice presents with dark urine and normal stools?
mixed/intra-hepatic jaundice
32
which part of the hypothalamus controls appetite?
arcuate nucleus
33
does ghrelin promote or inhibit hunger?
promote
34
which hormone inhibits hunger?
leptin
35
what is required for the activation of pepsin from pepsinogen?
HCl to achieve optimal pH2
36
what types of contractions are triggered by the filling of your stomach?
segmenting contractions (small intestine) mass movements (large intestine)
37
what are the main substances absorbed in the duodenum, jejunum and ileum?
duodenum: iron jejunum: folate ileum: vitamin b12
38
Which of the following mediators can suppress gastrin/histamine regulation of gastric acid secretion? a. prostaglandin b. dopamine c. ACh d. amoxicillin
prostaglandin prostaglandin and somatostatin inhibits gastric acid secretion
39
Which of the following enzymes does the pancreas secrete in its inactive (precursor) state? a. cholesterol elastase b. chymotrypsin c. lipase d. amylase
b. chymotrypsin