GI System Flashcards

1
Q

What do bile salts do?

A

Emulsify fat

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2
Q

What is blood detoxification?

A

Liver takes water insoluble compounds, adds chem groups to make them water soluble, allowing the kidneys to excrete them

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3
Q

Microsomal enzymes/P450 system refers to

A

Liver enzymes

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4
Q

What do microsomal enzymes do?

A

Inactivate compounds

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5
Q

If a person has low levels of microsomal enzymes, what effects do drugs have on them?

A

Bigger effects

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6
Q

If a person has higher levels of microsomal enzymes, what effects do drugs have on them?

A

Lower effects

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7
Q

When does jaundice occur in adults?

A

If bile secretion is blocked or liver is nonfunctional

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8
Q

What is hepatotoxicity

A

Liver disease

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9
Q

What are the 3 phases of control

A
  1. cephalic phase
  2. gastric phase
  3. intestinal phase
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10
Q

Cephalic phase

A

Vagus n. stimulates gastric secretion before food is swallowed.

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11
Q

Gastric phase

A

Food stretches stomach activating myenteric & vagovagal reflexes.
Gastric secretion stimulated.
Histamine & gastrin also stimulate acid & enzyme secretion.

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12
Q

Intestinal phase

A

Arriving of chyme into duodenum. Gastric function stopped due to inhibitory signals being sent.

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13
Q

What are enterogastrones

A

Hormones that inhibit gastric motility

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14
Q

Types of enterogastrones

A
  1. GIP (gastroinhibitory peptide)
  2. CCK (cholecystokinin)
  3. Secretin
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15
Q

GIP

A

Stimulates pancreatic insulin production from islets; secreted by duodenum in response to carbs & lipids

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16
Q

CCK

A

Secreted in response to fat & protein in chyme

Stimulates gallbladder contraction & release of pancreatic juice

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17
Q

Secretin

A

In response to acidic intestinal pH

Stimulates bicarb from panreas

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18
Q

What does the ENS control

A

Neurons & glia in gut

Interconnected by outer myenteric & inner submucosal

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19
Q

What does the outer myenteric control

A

Motor activity

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20
Q

What does the inner submucosal control

A

Secretion, absorption, local blood flow

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21
Q

Sensory Neurons

A

Extrinsic afferents: travel outside of gut

Intrinsic afferents: localized

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22
Q

Intestinal reflexes

A

Gastroileal reflex: increased motility of ileum
Ileogastric reflex: distension of ileum, decreased gastric motility
Intestino-intestinal reflex: overdistension of 1 segment - relaxation of rest of intestine

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23
Q

What is in pancreatic juice

A

Bicarb- to help neutralize acid in stomach

Enzymes

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24
Q

CCK

A

Secreted in response to protein & fat in duodenum

Stimulates release of pancreatic enzymes

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25
Q

What does secretin get produced in response to

A

Acid

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26
Q

Digestion beings in the

A

Mouth

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27
Q

Exocrine V. Endocrine secretion

A

Exocrine: secrete into duct; far reaching
Endocrine: secrete into bloodstream; work locally; hormones

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28
Q

What does digestion do?

A

Breaks food down into smaller subunits

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29
Q

Chemical breakdown

A

Breaking of CHEMICAL BONDS by small intestine

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30
Q

Mechanical breakdown

A

Chewing/ churning of stomach

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31
Q

What is absorption?

A

Going from lumen of digestive tract into bloodstream or lymph

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32
Q

What happens after absorption?

A

Delivered to tissue for energy storage

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33
Q

Lymph absorbs..

A

Fats

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34
Q

What is the problem with digestion?

A

Enzymes can digest tissue of digestive tract

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35
Q

Which get absorbed?

A

Fatty acids, monosaccharides, & amino acids

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36
Q

Peristalsis

A

Moves forward

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37
Q

Where does peristalsis occur

A

The esophagus, stomach, & intestines

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38
Q

Digestive system function

A

Motility, ingestion, secretion

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39
Q

Mastication

A

Chewing

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40
Q

Deglutition

A

Swallowing

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41
Q

What does digestion allow

A

Absorption

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42
Q

Where is food stored & why?

A

In stomach to get a continuous stream of nutrients entering blood, so that you don’t need to eat continuously

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43
Q

Purpose of HCL

A

Provides a nonspecific immune defense against ingested pathogens

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44
Q

Peyers patches

A

Area of lymphoid tissue in intestinal tract; also protect against pathogens https://image.slidesharecdn.com/lymphaticsystemnotes-120330134955-phpapp01/95/lymphatic-system-notes-14-728.jpg?cb=1333115791

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45
Q

What protects immune function?

A

Tight junctions, Hcl, Peyers patches

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46
Q

Digestive tract refers to

A

Mouth –> anus

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47
Q

GI tract refers to

A

Stomach & intestines

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48
Q

Which layer is in contact with ingested food

A

Mucosa

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49
Q

Layers of the GI tract

A

Mucosa: innermost; lines lumen
Submucosa: below mucosa
Muscularis:
Serosa: outer connective

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50
Q

Goblet cell function

A

Produce mucus; helps things move along

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51
Q

Submucosal plexus

A

Regulates secretion; located in submucosa

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52
Q

Mucosa function

A

Absorption & secretion; lines lumen; simple columnar epithelium; has goblet cells

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53
Q

Submucosa function

A

Secretion; contains glands & nerve plexuses; vascular connective tissue layer

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54
Q

ENS function

A

Detects pH, detects food ingested, has sensory neurons (brain of the GI system)

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55
Q

How is food broken down?

A

Proteins –> amino acids
Fats –> fatty acids & glycerol
Carbs –> monomeric sugars

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56
Q

What is segmentation?

A

Mixing with digestive enzymes

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57
Q

Muscularis function & components

A

Segmentation & peristalsis; Inner circular & outer longitudinal layer; smooth muscle; myenteric plexus

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58
Q

Myenteric plexus innervation & location

A

Innervation: sympathetic & parasympathetic
Location: between 2 muscle layers

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59
Q

Myenteric plexus function

A

Major nerve supply to GI tract; movement contraction or relaxation of muscle layers

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60
Q

Esophagus connects

A

Pharynx –> stomach

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61
Q

Esophagus

A

Voluntary –> Involuntary; posterior to trachea; stratified squamous

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62
Q

Peristalsis of Bolus

A

Step 1: contraction of circular muscles behind food mass
Step 2: contraction of longitudinal muscles ahead of food mass
Step 3: contraction of circular muscle layer forces mass forward

63
Q

Stomach empties into

A

Duodenum

64
Q

Stomach function

A

Food storage & elimination, begin protein digestion, bactericidal (i.e hcl), chyme production

65
Q

Purpose of layered muscles in stomach

A

Strength & support; for chyme production

66
Q

Receptive relaxation reflex

A

Stomach relaxed when you swallow food allowing stomach to distend so you can eat more

67
Q

What happens to chyme that doesn’t make it to duodenum?

A

Turned back into stomach, churned more, a bit sent to intestines

68
Q

What happens if too much chyme is sent at once?

A

Too much acidity; buffering capacity overwhelmed; pH of intestines will be acidic; enzymes won’t work; possible ulcerations of duodenum

69
Q

What if duodenum becomes overfilled?

A

Gastric motility inhibited

70
Q

When does salivary amylase stop functioning?

A

When food gets to stomach b/c saliva has a neutral-basic pH & stomach has an acidic pH

71
Q

T/F: The stomach does nutrient absorption

A

False; stomach does breakdown; mostly mechanical

72
Q

What are rugae?

A

Inner surface folds (macroscopic)

73
Q

Gastric pits

A

Openings of folds in gastric mucosa

74
Q

Chief cells produce

A

Pepsinogen

75
Q

Enterochromaffin cells secrete

A

Histamine & seratonin

76
Q

G cells produce

A

Gastrin

77
Q

D cells

A

Stomatostatin (inhibits digestive function)

78
Q

Stem cells produce

A

New epithelium

79
Q

Parietal cells

A

Hcl in stomach; intrinsic factor

80
Q

Intrinsic factor

A

Secreted by parietal cells for B12 absorption

81
Q

B12 is for

A

RBC production

82
Q

What is pernicious anemia?

A

Not enough b12 for RBC production from not producing intrinsic factor
Tx: B12 injection NOT oral

83
Q

What is gastric juice composed of?

A

Exocrine secretions, water, pepsin & hcl

84
Q

How much gastric juice produced/day

A

2-4 L/day

85
Q

What does the proton pump do?

A

Takes H ions –> stomach lumen in exchange for K; Bicarb –> blood; PUMPS PROTONS INTO STOMACH LUMEN

86
Q

What are proton pump inhibitors?

A

Reduce acidity in stomach b/c H ions don’t go out = no acid produced (i.e omeprazole)

87
Q

What stimulated hcl production strongly?

A

Histamine

88
Q

What stimulates adic production?

A

Gastrin, histamine, neurotransmitters, exercise, caffeine

89
Q

Stomach acid funciton

A

Denature proteins; activates pepsinogen –> pepsin; provides optimal pH for pepsin; kills microbes

90
Q

Most digestion & absorption occurs in the

A

S. intestine

91
Q

Peptic ulcers

A

Erosion of stomach or duodenal mucosal membranes due to hyperacidity

92
Q

Gastic ulcer cause

A

Depletion of mucous coat

93
Q

Duodenal ulcer

A

Hyper-acidic conditions

94
Q

Zollinger Ellison Syndrome

A

Gastrin secreted tumor (rare); produced by duodenal ulcers

95
Q

H. Pylori

A

Cause of most gastric & duodenal ulcers; Tx: antibiotics & proton pump inhibitor

96
Q

Small Intestinal Mucosa

A

Plicae circularis, villi, microvilli (brush border)

97
Q

Enterokinase

A

For trypsin activation (brush border enzyme)

98
Q

Segmentation

A

Muscular constrictions in lumen; churning

99
Q

Intestinal microbiota function

A

Produce vitamin K & folic acid; ferment; outcompete pathogens; anti-inflammatory actions

100
Q

If the stomach pumped it’s contents all at once into the duodenum, how would this affect the activity of the enzymes within the s. intestine?

A

Activity would decrease; enzymes would go from neutral –> basic –> acidic; they don’t work well under acidic conditions

101
Q

NSAIDS result in stomach ulcerations by…

A

Inhibition of posteglandin synthesis ( is what stimulates mucous coat formation)

102
Q

Defecation

A

Sphincters relax; rectal muscles contract

103
Q

Liver function

A

Bile production & secretion –> fat emulsification; detoxification of compounds; largest internal organ

104
Q

MMCs (migratory motor complexes)

Hint: guy in commercial

A

occurs in between meals to prevent bacterial growth; stops when eating begins

105
Q

Significance of increase S.A

A

For digestion & absorption to occur more effectively

106
Q

Gastroesophageal junction

A

Where esophagus ends & stomach begins

107
Q

Gastroesophageal sphincter

A

Thick circular muscle that prevents back flow from stomach; if doesn’t close right: acid reflux –> ulcers; not fully functional in babies hence spit up after meals; not a true sphincter

108
Q

LDL

A

Transports cholesterol to organs & vessels –> atherosclerosis

109
Q

HDL

A

Returns cholesterol to liver aka good cholesterol

110
Q

T/F: We want high ratio of LDL

A

False. HDL

111
Q

What happens when LDL circles around the body?

A

Deposits cholesterol in sub-endothelial lining of vessels –> atherosclerotic plaque formation –> coronary artery disease

112
Q

The higher the HDL is thought to be

A

Cardio protective against pulmonary artery disease & lower your risks of plaque deposit

113
Q

VLDL converted into

A

LDL

114
Q

If the liver needs cholesterol..

A

It will use LDL & convert them into bile salts

115
Q

If the liver does not need cholesterol..

A

LDL will circulate around the body (not good)

116
Q

Reverse cholesterol transport

A

HDL picks up some of LDL brings it back to liver; protective

117
Q

Myenteric plexus regulates

A

Motility

118
Q

Submucosal plexus regulates

A

Secretion

119
Q

Smooth muscle is under what control

A

Involuntary

120
Q

The parasympathetic innervation of the myenteric plexus stimulates what?

A

Motility

121
Q

Swallowing is under what control?

A

Voluntary

122
Q

Peristalsis is under what control?

A

Involuntary; by smooth muscle

123
Q

Esophagus is found in areas subject to what?

A

Abrasion

124
Q

Peristalsis moves what?

A

Bolus

125
Q

What begins the digestion & absorption phase?

A

Salivary & gastric enzymes

126
Q

What do tight junctions do?

A

Keep acid & pepsin within lumen

127
Q

New stomach lining every ___ days

A

3

128
Q

Why do people with hyper-acidic conditions present with duodenal ulcers instead of stomach ulcers?

A

Because the stomach is really well protected by mucous coat

129
Q

Chronic use of NSAIDs does what

A

Corrodes mucous coat

130
Q

What can h. pilori lead to?

A

Produces mucinase which degrades mucous coat –> stomach exposed –> stomach ulcers

131
Q

Mucous production is stimulated by

A

Prostaglandins

132
Q

T/F: ASA & NSAIDS inhibit prostaglandin synthesis

A

True

133
Q

What are peptic ulcers?

A

Erosions of stomach or duodenal mucous membranes

134
Q

Cause of a gastric ulcer

A

Depletion of mucous coat

135
Q

Cause of a duodenal ulcer

A

Hyperacidity

136
Q

What happens when more gastrin is produced than should

A

Stomach acid increases –> duodenal ulcer

137
Q

Mucinase V . Urease

A

Mucinase erodes mucous lining of stomach, urease neutralizes gastric acid

138
Q

Why is a proton pump inhibitor used to treat h. pylori?

A

To heal area & stop acid production

139
Q

What is gastritis?

A

Inflammation of stomach mucosa caused by a breakdown of protective barriers

140
Q

Gastritis: What is released due to inflammation?

A

Histamine –> acid production

141
Q

Tx : gastritis

A

H2 blockers (i.e zantac)

142
Q

What protects the duodenum?

A

Bicarb

143
Q

What do mucosal cells & brunner’s glands release?

A

Bicard

144
Q

Pancreatic & bile secretions are..

A

Alkaline

145
Q

Enterokinase is required for

A

Trypsin activation

146
Q

Which intestine absorbs more water?

A

S. intestine

147
Q

Causes of diarrhea

A

Enterotoxin & lactose intolerence

148
Q

Why is enterotoxin a cause of diarrhea?

A

Keeps sodium & water in lumen

149
Q

Causes of cirrhosis

A

chronic alcohol use, biliary obstruction, viral hepatitis, hepatotoxic chemicals

150
Q

What gives feces its brown color & urine its amber color?

A

Bile pigments

151
Q

What is the result of bile pigments accumulating due to a nonfunctioning liver?

A

Jaundice

152
Q

What does the blue lamp do for babies with jaundice?

A

Converts bilirubin –> water soluble form

153
Q

What shuts off acid production?

A

Negative feedback