Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HUBS192 Lectures 1-38 > HUBS192 Lecture 25 - GI Secretion > Flashcards

HUBS192 Lecture 25 - GI Secretion Flashcards

1
Q

what are exocrine secretions?

A

secretions into the lumen of the GI tract

-secreted outside onto the body surface (therefore it is referred to as exo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are endocrine secretions?

A

secretions into the blood, into the body or secreted into the interstitial fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are exocrine secretions produced by?

A

produced by epithelia that line the surface of the GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the components and functions of these components of exocrine secretions?

A

1) mucous
- protection and lubrication
- aids mechanical digestion
2) electrolyte solution
- dilutes food & provides optimal pH
- essential for chemical digestion of food
3) digestive enzymes
- essential for chemical digestion of food
- aids absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the 2 functions of electrolyte solution?

A

1) dilutes food
2) provides optimal pH
- which is essential for chemical digestion of food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what are the 2 functions of digestive enzymes?

A

1) essential for chemical digestion of food

2) aids absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the 3 pairs of salivary glands?

A

1) parotid glands
2) submandibular glands
3) sublingual glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which gland produces the largest proportion of salivary secretion?

A

the submandibular glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how many litres do the salivary glands produce per day?

A

1.5 L of fluid per day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the basal secretion of salivary glands?

A

0.3 mL/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the stimulated secretion of salivary glands?

A

1.5 mL/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the composition of the salivary glands?

A

1) mucous
- lubrication
2) dilute solution of NAHCO3/NaCI
- dilution of food
- optimal pH for digestive enzymes
3) digestive enzymes
- lingual lipase
- alpha amylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the functions of salivary secretion?

A

1) aids in
- talking
- chewing
- swallowing
- dissolves food
- lubricates
2) hygiene
- irrigation
3) digestion
- dissolves food to allow tasting
- lingual lipase (fats)
- alpha amylase (starch)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

are salivary secretions essential?

A

no they are not essential but are preferred

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 2 regulators of salivary secretion?

A

1) nervous control

2) autonomic nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how does the nervous control regulate salivary secretion?

A

by the thought, smell, sight of food and the presence of food in the mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the 2 nervous systems that control the salivary secretion from the autonomic nervous system?

A

1) parasympathetic nervous system

2) sympathetic nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the function of the parasympathetic nervous system in terms of salivary secretion?

A

stimulates the secretion of copious quantities of fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the function of the sympathetic nervous system in terms of salivary secretion?

A

stimulates the secretion of small volumes of viscous fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the volume of gastric secretion per day?

A

2-3 L per day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the volume of gastric secretion between meals?

A

slow rate of 15-30 mL/hour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the cells of gastric secretion secretion between meals?

A

surface cells secrete mucous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the gastric secretion when eating?

A

superimposed on basal rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the 3 cells involved in gastric secretion when eating?

A

1) mucous cells
2) parietal cells
3) chief cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what do parietal cells secrete?

A

150 mLs/hour of HCI acid (pH=1) and intrinsic factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what do chief cells secrete?

A

pepsinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the function of intrinsic factor?

A

the absorption of vitamin B12 in the small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is pepsinogen?

A

the inactive form of pepsin that is a gastric proteolytic enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is the largest component of gastric secretions?

A

gastric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is the function of pepsinogen?

A

starts the digestion of proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are the 5 functions of gastric acid?

A

1) dilutes food
2) denotes proteins
3) activates pepsinogen to pepsin
4) creates optimum pH for pepsin action
5) protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the active form of pepsinogen and how is this converted?

A

converted to the active form of pepsin by acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is the source of HCI acid for gastric secretion?

A

the parietal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

how is the source of H+ for HCI acid generated?

A

source of H+

  • comes from the formation of H2CO3 by carbonic anhydrase (CO2 + H2O H2CO3)
  • dissociation of H2CO3 HCO3- + H+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how is the secretion of H+ for HCI acid generated?

A

ATP drives the pumping of H+ across the apical membrane of parietal cells into the lumen of the stomach in exchange for K+ (potassium ions)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

how is the source of CI- for HCI acid generated?

A

through an anion counter transporter on the serosal membrane of parietal cells by ejecting HCO3- into the interstitial fluid and importing CI- ions into the cell

37
Q

how is the secretion of CI- for HCI acid generated?

A

CI- ions diffuse across the cells and enter the lumen via a CI- channel in the apical membrane

38
Q

how is the regulation of gastric secretion co-ordinated by?

A

co-ordinated with eating and the arrival of food

39
Q

what are the 3 phases of gastric secretion?

A

1) cephalic phase
2) gastric phase
3) intestinal phase

40
Q

what controls the cephalic phase of gastric secretion?

A

head controls secretion

41
Q

what controls the gastric phase of gastric secretion?

A

stomach controls secretion

42
Q

what controls the intestinal phase of gastric secretion?

A

intestine controls secretion

43
Q

what is the purpose of cephalic phase?

A

prepares for the arrival of food

44
Q

how is the parasympathetic nervous system via the enteric nervous system stimulated by?

A

stimulation of higher centres by the thought, smell, sight of food, chewing and taste

45
Q

what does the parasympathetic nervous system via the enteric nervous system stimulate?

A
  • stimulates parietal cells, chief cells and goblet cells
  • stimulates the secretion of the hormone gastrin that are released into the blood and stimulates parietal cells and chief cells
46
Q

what is the purpose of the gastric phase?

A

ensures sufficient secretion to handle ingested food

47
Q

what does the stimuli in the stomach detect?

A

1) stretch/distention of the stomach wall
2) products of digestion stomach lumen
3) elevated pH

48
Q

what are the 2 nervous and hormonal regulation reflexes?

A

1) local nervous reflex

2) external nervous reflex

49
Q

what nervous system does the local nervous reflex innervate?

A

the enteric nervous system

50
Q

what nervous system does the external nervous reflex innervate?

A

the parasympathetic nervous system

51
Q

what do the local nervous reflex and the external nervous reflex stimulate?

A
  • secretion
  • motility
  • gastrin secretion (further simulation of secretion and motility)
52
Q

what 3 hormones inhibit gastric secretion and motility?

A

1) GIP
2) CCK
3) Secretin

53
Q

what is the purpose of the intestinal phase?

A

controls the delivery to the small intestine

54
Q

what does the stimuli in the small intestine detect?

A
  • distention of the duodenum

- arrival in the duodenum of acid chyme, lipids ad carbohydrates

55
Q

what are the 2 nervous and hormonal regulation components that inhibit secretion and motility?

A

1) hormones

2) nerves

56
Q

what is the nerve that inhibits gastric secretion and motility?

A

enterogastric relex nerve

57
Q

how much fluid volume does the pancreas secrete per day?

A

1-1.5 L/per day

58
Q

what are the 2 components of pancreatic secretion?

A

1) enzymes which secrete acing cells for chemical digestion

2) alkaline fluid produced in duct cells that neutralise acid to make an optimum pH for the digestive enzymes

59
Q

what are the lipolytic enzymes?

A

lipase and phospholipase

60
Q

what are the amylytic enzymes?

A

pancreatic amylase

61
Q

what are proteolytic enzymes?

A

trypsin, chymotrypsin and carboxypeptidase

62
Q

what are nucleolytic enzymes?

A

ribonuclease and deoxyribonuclease

63
Q

what are the pancreatic enzymes secreted by?

A

secreted by acinar cells

64
Q

what do pancreatic enzymes stimulate the secretion of?

A

secretion of digestive enzymes by acinar cells stimulated by the cholecystokinin hormone (CCK)

65
Q

what stimulates cholecystokinin secretion?

A

arrival of lipids and carbohydrates into the duodenum

66
Q

what is the function of digestive enzymes?

A

luminal chemical digestion of food

67
Q

what are proteolytic enzymes secrete as and what are they activated by?

A

secreted as inactive precursors and activated in the duodenum

68
Q

what is the inactivate precursor of trypsin?

A

trypsinogen

69
Q

what is the inactive precursor of chymotrypsin?

A

chymotrypsinogen

70
Q

what is the inactive precursor of carboxypeptidase?

A

procarboxypeptidase

71
Q

what does activation in the small intestine involve?

A

enterokinase (or enteropetidase) bound to the duodenal membrane that converts trypsinogen trypsin

72
Q

what is the function of trypsin?

A

trypsin converts other enzymes the active form

73
Q

where is the secretion of alkaline (HCO3 rich) fluid produced by?

A

produced by duct cells in the pancreas

74
Q

what is the secretion of alkaline (HCO3 rich) fluid?

A

stimulated by hormone secretion

-secretion of secretin by the arrival of acidic chyme in the duodenum

75
Q

what is the function of alkaline (HCO3 rich) fluid?

A

-neutralises acid chyme delivered to the stomach creating the optimum pH (6.7-9.0) for pancreatic and intestinal digestive enzymes

76
Q

how much bile fluid is secreted by the liver per day?

A

0.5 L/per day

77
Q

what are the products associated with digestion of bile secretion?

A
  • bile salts

- HCO3- rich fluid from ducts

78
Q

what are the excretory products of bile secretion?

A
  • bile pigments (waste products)

- cholesterol

79
Q

what is the function of bile salts?

A

fat digestion

80
Q

what is the function of HCO3- rich fluid?

A

-neutralises acid

81
Q

what is the function of bile pigments?

A

excretion of the liver

82
Q

what stimulates bile secretion?

A

bile stimulates its own secretion by enterohepatic circulation

83
Q

where is bile stored and concentrated?

A

in the gallbladder

84
Q

where is bile delivered to with the arrival of food?

A

delivered to the duodenum

85
Q

what does the hormone cholecystokinin (CCK) do in relation to the initial delivery of bile that is under hormonal control?

A
  • produced in response to products of digestion in the duodenum
  • contracts the gallbladder
  • relaxes the hepatopancreatic ampulla
86
Q

what is the hormone secretin mildly stimulated by?

A

mild stimulation of bile by the liver

87
Q

what percentage of enterohepatic circulation is reabsorbed into the ileum?

A

95%

88
Q

what does GIP stand for?

A

gastro inhibitory peptide

HUBS192 Lectures 1-38 (38 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions