GI Tract Flashcards

1
Q

_____ extends from oral cavity to anus

A

Alimentary canal

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2
Q

What are the 5 phases of digestion?

A

Ingestion, fragmentation, digestion, absorption, and elimination

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3
Q

____ occurs in the oral cavity and is accompanied by fragmentation

A

ingestion

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4
Q

Ingestion occurs in the oral cavity and is accompanied by _______

A

fragmentation

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5
Q

Stomach completes fragmentation and initiates _______

A

digestion

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6
Q

Contractions of smooth muscle are called

A

peristalsis

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7
Q

Peristalsis is under ____ control

A

autonomic control

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8
Q

In duodenum, pancreatic & biliary secretions lead to ______

A

emulsification of fat

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9
Q

In jejunum & ileum, 1’ function is ______

A

absorption of nutrients

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10
Q

In colon, the primary function is _____ and ______

A

resorption of water & elimination of waste

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11
Q

The GI tube is a muscular tube lined by ______

A

mucus membrane

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12
Q

____ is scattered throughout the GI tract for lymphatic function

A

GALT

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13
Q

What are the 4 distinct layers of the GI tract?

A

mucosa, submucosa, muscularis externa & adventitia

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14
Q

the ____ layer of the GI tract functions in protection, secretion, and absorption

A

mucosa

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15
Q

What are the 3 layers of the mucosa layer of the GI tract?

A

epithelium, lamina propria, and muscularis mucosae

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16
Q

secretory & absorptive functions; different modifications at different levels of GI tract

A

epithelium

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17
Q

Layer of mucosa of GI tract: underlying connective tissue; contains lymphoid nodules, glands, blood vessels & lymphatics

A

lamina propria

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18
Q

Layer of mucosa of GI tract: thin layer of smooth Mm; boundary between mucosa & submucosa

A

muscularis mucosae

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19
Q

Layer of loose to dense irregular connective tissue layer beneath muscularis mucosae

A

Submucosa

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20
Q

Layer of GI tract: Supports mucosa, contains larger blood vessels, Nn, lymphatics

A

Submucosa

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21
Q

Layer of GI tract: usually inner circular & outer longitudinal smooth Mm layers; Mm fibers oriented at right

A

Muscularis externa(= propria)

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22
Q

local contractions => mixing of foodOccur both proximally & distally, in either direction

A

Segmentation

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23
Q

Peristalsis propels food in what direction?

A

Distally (aborally)

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24
Q

What kind of epithelium makes up the adventitia layer of the GI tract?

A

simple squamous epithelium

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25
Q

Layer of GI tract: outer loose connective tissue layer, contains major Nn, vessels, & adipose tissue•Within abdominal cavity, referred to as serosa(

A

Adventitia

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26
Q

Smooth Mm of gut controlled by ______ nervous sys

A

autonomic

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27
Q

parasympathetic stimulation of GI tract is (excitatory or inhibitory)

A

excitatory

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28
Q

sympathetic stimulation of GI tract is (excitatory or inhibitory)

A

inhibitory

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29
Q

Where are parasympathetic ganglia of gut located within wall of gut?

A

within submucosa and muscularis externa

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30
Q

Clusters of parasympathetic ganglia within submucosa; called _____

A

Meissner’s plexus

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31
Q

Larger clusters of parasympathetic ganglia located between inner circular & outer longitudinal Mm layers called ______

A

myenteric or Auerbach’s plexus

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32
Q

Short, muscular tube, lined by stratified squamous nonkeratinized epithelium

A

esophagus

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33
Q

In upper third of esophagus, muscularis externa composed of _____

A

voluntary skeletal Mm

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34
Q

In middle third of esophagus, muscularis externa composed of _____

A

skeletal and smooth muscle

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35
Q

In lower third of esophagus, muscularis externa composed of _____

A

smooth muscle only

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36
Q

Gastro-esophageal junction between esophagus & stomach contains ______

A

gastroesophageal sphincter

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37
Q

_____ is due to regurgitation of stomach acid into distal esophagus from cardia of stomach

A

Pyrosis—(aka “heartburn”)

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38
Q

surrounded by smooth Mm cardiac sphincter(= gastroesophageal sphincter) adjacent to esophagus; contains predominantly mucus-secreting glands

A

cardia

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39
Q

glandular portion of stomach; secretes acid, pepsin, & some mucus

A

fundus

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40
Q

contains 1’ mucus (& gastrin) secreting glandsSmooth Mm pyloric sphincter controls outflow from stomach into duodenum

A

pylorus

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41
Q

_____ controls outflow from stomach into duodenum

A

pyloric sphincter

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42
Q

_______ is loss of stomach/duodenal epithelium/ mucosa

A

Peptic/gastric ulcer

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43
Q

_______ is damage extends below level of basement membrane (=> bleeding)

A

Ulcer

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44
Q

_____ is partial loss of epithelium (no bleeding)

A

Erosion

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45
Q

How do you treat peptic ulcers and erosion?

A

antacids

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46
Q

Ulcers frequently associated with chronic infection with _____

A

Helicobacter pylori

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47
Q

Helicobacter pylori produces _____=> ↑ gastric pH => 2’ ↑ acid production

A

urease

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48
Q

How do you treat H. pylori from producing urease?

A

triple therapy”—2 long-term abx & proton pump inhibitor

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49
Q

Distensible organ used for food storage; Single chamber in most animals

A

stomach

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50
Q

Food undergoes mechanical breakdown via muscular activity & chemical breakdown via gastric secretions to form ______

A

chyme

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51
Q

In addition to inner circular & outer longitudinal Mm layers of stomach, also third _______ layer in muscularis externa

A

inner oblique

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52
Q

T/F: There is a lot of absorption that happens in the stomach

A

False

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53
Q

What is absorbed in the stomach?

A

water, alcohol, and some drugs

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54
Q

Stomach lining contains prominent longitudinal folds that increase surface area are called _____

A

rugae

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55
Q

In glandular bodyof stomach, mucosa contains prominent _______; Form entrance to gastric glands(straight, tubular glands), secrete ~2 liters watery gastric juice/ day

A

gastric pits

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56
Q

(straight, tubular glands), secrete ~2 liters watery gastric juice/ day

A

gastric glands

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57
Q

What are the things that gastric juice contains

A

HCl, pepsinogen, gastrin, rennin, & lipase

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58
Q

inactive precursor of pepsin, hydrolyzes protein)

A

pepsinogen

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59
Q

Pepsinogen converted to pepsin by action of ____

A

HCl

60
Q

Mucosa itself protected by thick layer of _____

A

mucus

61
Q

Cover luminal surface & upper third of pit; renewed q 3-5/ 4-7 days;

A

mucus secreting cells

62
Q

secrete thick, insoluble mucus & bicarbonate ions; located on surface

A

surface mucus cells

63
Q

secrete soluble mucus; located in upper third of pit, at neck of gastric gland

A

mucus neck cells

64
Q

Secrete HCl& intrinsic factor(necessary for absorption of Vit B12 from ileum)•Most numerous in middle third of gland, stain pink to purple

A

acid secreting cells (parietal cells)

65
Q

Secrete inactive pepsinogen•Located at base of gland (bottom third); stain purple due to large #’s of ribosomes

A

pepsin secreting cells (chief cells)

66
Q

Parietal & chief cells controlled by _____ nervous system & hormones from endocrine cells in region of ______

A

autonomic; pylorus

67
Q

Paracrine cells that Secrete variety of peptide hormones in response to local factors; control GI motility, gastric secretion

A

Enteroendocrine cells (APUD)

68
Q

stimulates secretion of HCl & pepsin;

A

gastrin

69
Q

Gastrin is secreted by ____ cells

A

G cells

70
Q

Somatotropin is secreted by ____ cells

A

D cells

71
Q

____ inhibits secretion of gastrin

A

Somatotropin

72
Q

_____ inhibits gastric secretion & stimulates smooth Mm contraction

A

secretin

73
Q

Secretin is secreted by ____ cells

A

S cells

74
Q

_____ are mainly in neck of gland; Continuously divide to replace lost or damaged epithelial cells; As mature, migrate up or down gland

A

Undifferentiated stem cells

75
Q

Where are the undifferentiated stem cells located in gastric gland?

A

neck of gland

76
Q

_____ is the primary site of absorption

A

small intestine

77
Q

Mucosa & submucosa throughout small intestine arranged in valve-like folds/ rings called ______ ; ↑surface area, contain submucosalcore

A

plica circulares(= valves of Kerkring)

78
Q

Plica circulares are particularly prominent in what segment of small intestine?

A

jejunum

79
Q

Mucuosal surface of small intestine made up of ____ which contain a core of ______

A

villi; lamina propria

80
Q

____ are between villi

A

crypts of Leiberkuhn

81
Q

Causes villus blunting & atrophy => malabsorption & weight loss

A

Coeliac disease(gluten enteropathy)

82
Q

Epithelium of villi supported by ______, containing _____ and ______ for absorption of nutrients

A

connective tissue lamina propria; capillaries & lymphatics

83
Q

Intestinal villi lined by _______ epithelium

A

simple columnar epithelium

84
Q

Mucosal cells of the small intestine called ______, cover surface of villi

A

enterocytes

85
Q

Apical/ luminal surface of villi highly folded, modified into ______ that ↑surface area for absorption;

A

microvilli(= striated or brush border)

86
Q

Microvilli coated with protective ____ of disaccharides (site of membrane digestion)

A

glycocalyx

87
Q

Interspersed among enterocytes are mucus secreting _____ cells ; Synthesize mucinogen

A

goblet cells

88
Q

stored in membrane-bound granules; lubricates & protects epitheium

A

mucinogen(=> mucus)

89
Q

Actively dividing ____ located at base of crypts of villi

A

stem cells

90
Q

T/F: Cells migrate up villus, mature, & are shed

A

True

91
Q

How often is the entire epithelial lining of small intestine replaced?

A

Every 3-5 days

92
Q

_____ cells are found at base of crypts; contain large eosinophilic granules—produce antibacterial proteins called defensins, and enzymes, including lysozyme

A

Paneth cells

93
Q

“S” cells secrete _____ (stimulate release of bicarbonate from pancreas)

A

secretin

94
Q

I” cells secrete _____ (stimulates pancreatic secretion & contraction of gallbladder)

A

cholecystekinin, or CCK

95
Q

stimulates pancreatic secretion & contraction of gallbladder

A

cholecystekinin, or CCK

96
Q

“A” cells secrete _____ (↑ blood sugar)

A

glucagon

97
Q

K” cells secrete

A

GIP (gastric inhibitory peptide)

98
Q

_____ located in lamina propria & submucosa of small intestine•Contains plasma cells, sec IgA

A

MALT

99
Q

Epithelium contains enlarged _______ —squamoid enterocytes modified for Ag sampling, uptake of macromolecules

A

“M” cells(microfold)

100
Q

dome-shaped areas grossly visible on surface of mucosa, project into lumen

A

Peyer’s patches

101
Q

Characterized by presence of Brunner’s glands in submucosa

A

duodenum

102
Q

Large #’s of highly convoluted, branched, tubuloalveolar submucosal glands; Secrete mucus & zymogens; unique to duodenum

A

Brunner’s glands

103
Q

Main function of ______—neutralize gastric acid & pepsin, assisted by pancreas & gallbladder

A

duodenum

104
Q

_____ and _____ empty into duodenum at major duodenal papilla

A

Pancreatic duct & bile duct

105
Q

Chyme from stomach stimulates release of 2 hormones from APUD cells—____ and ____; Both promote section of exocrine pancreas

A

secretin & CCK

106
Q

Pancreatic secretions highly ______, due to ______ which neutralize stomach acid

A

alkaline; bicarbonate

107
Q

____ also stimulates contraction of gallbladder & release of bile acids

A

CCK

108
Q

_____ act as emulsifying agents for digestion of lipids, form micelles

A

bile acids

109
Q

Pancreatic secretions also contain proteolytic enzymes ____ and ____ for digestion of proteins

A

trypsin & chymotrypsin

110
Q

In addition to trypsin & chymotrypsin, pancreatic secretions also contain ___ and _____ (proteolytic enzymes for digestion of proteins)

A

amylase and lipase

111
Q

trypsin & chymotrypsin are secreted as ______

A

inactive precursors or zymogens

112
Q

trypsin activated by ____

A

enterokinase

113
Q

trypsin then activates ______

A

chymotrypsin

114
Q

What are the 2 steps of digestion?

A

luminal digestion and membrane digestion

115
Q

____ digestion involves mixing of chyme with pancreatic enzymes => molecular breakdown

A

luminal digestion—

116
Q

____ digestion involves enzymes of glycocalyx on plasma membrane of enterocytes

A

membrane digestion—

117
Q

______ synthesize various enzymes, (peptidases, peptide hydrolases, disaccharidases) &produce various carrier proteins for absorption of carbohydrates & AA’s

A

Enterocytes

118
Q

What enzymes do enterocytes synthesize?

A

peptidases, peptide hydrolases, disaccharidases

119
Q

____ initially denatured by HCl from parietal cells, then hydrolyzed by pepsin into polypeptide fragments•Continued by pancreatic enzymes—trypsin, chymotrypsin, elastase, & carboxypeptidase => formation of small peptide fragments, AA’s; absorbed by enterocytes via active transport by carrier proteins

A

Proteins

120
Q

______ and ______ hydrolyze starch to disaccharides (sucrose, lactose,maltose, & isomaltose); Further broken down into monosaccharides (glucose, galactose, & fructose), absorbed by facilitated diffusion

A

Salivary & pancreatic amylase

121
Q

AA’s & monosaccharides absorbed by ______ lining villi, transported across epithelium, enter capillaries within lamina propria => portal V to liver for storage

A

enterocytes

122
Q

1’ starches; poly-, oligo-, & disaccharides

A

Carbohydrates

123
Q

_____ 1’ triglycerides from diet, emulsified by action of bile acids

A

Lipids

124
Q

Lipids are Further broken down into monoglycerides & FA’s by _____, form extracellular micelles•

A

pancreatic lipase

125
Q

Micelles are absorbed by enterocytes, then re-synthesized into triglycerides within enterocytes & coated with proteins & phospholipids to form ______

A

intracellular chylomicrons

126
Q

Intracellular chylomicrons are transported across enterocytes to _____, blind-ended lymph vessels within lamina propria of villi

A

lacteals

127
Q

_____ includes cecum, apppendix; ascending, transverse, descending, & sigmoid colon, & rectum; lacks villi & plicae circulares

A

Large intestine

128
Q

small, blind-ended sac, 2-13 cm in length distal to ileo-cecal junction; Vestigial cecum; used for bacterial digestion in herbivores; Contains large amounts of submucosal MALT, active in children

A

Appendix

129
Q

1’ function, H2O & electrolyte resorption; also produces mucus for elimination of undigested food & waste; (large #’s of goblet cellsin epithelium & colonic glandsin submucosa—but no Brunner’s glands)

A

Colon

130
Q

No villi for nutrient absorption•No plicae circulares; mucosal folds contain core of lamina propria•Mucosal epithelium similar to small intestine, but Paneth cells generally absent in adults

A

Colon

131
Q

T/F: In the colon, MALT in large intestine form domed Peyer’s patches

A

False: does not form

132
Q

T/F: In the colon, No lacteals present in lamina propria

A

True

133
Q

Epithelial cell replacement of colon every ____ days from stem cells located at base of glandular crypts

A

5 days

134
Q

Outer longitudinal M layer in muscularis externa is reduced or incomplete—forms 3 longitudinal strips,______ Responsible for formation of haustra,

A

taenia coli

135
Q

sacculations of large intestine

A

haustra,

136
Q

T/F: Large #’s of commensal bacteria (“coliforms”) present in large intestine

A

True

137
Q

Any mass arising from the wall of the colon that protrudes into the lumen•Generally asymptomatic; most common sign, rectal bleeding•Tx: Sx removal

A

Polyps—adenoma

138
Q

↑ roughage & fiber in diet ↓ colon cancer by ↓ transit Fme & ↑ GI motility•Tx: Surgical removal; if extensive, may require resection of portion of colon•New test kits for early detection; detect tumor Ab; also colonoscopy screening over 50

A

Colon cancer—adenocarcinoma

139
Q

Short, dilated, terminal portion of large intestine•Contains transverse rectal folds and large #’s of mucus glands•Transition of mucosa from simple columnar epithelium to stratified squamous epithelium at anal canal

A

Rectum

140
Q

Anal canal contains longitudinal folds called ______

A

anal columns(= columns of Morgani)

141
Q

Within anal canal, _____ extend into submucosa & muscularis externa (branched, straight, tubular glands—secrete mucus)

A

anal glands

142
Q

Surrounding Mm forms ______ (external—voluntary, skeletal Mm; internal—involuntary, smooth Mm)

A

internal & external anal sphincters

143
Q

Anal sphincter that is voluntary and made up of skeletal muscle

A

external anal sphincter

144
Q

Anal sphincter that is involuntary and made up of smooth muscle

A

internal anal sphincter

145
Q

Occasional enlargement & irritation of submucosal Vv~ anal canal =>_____ (like varicose Vv)

A

hemorrhoids

146
Q

external opening; exit of GI tract

A

Anus