Digestive System Flashcards

1
Q

Organs of digestive system

A

alimentary canal and accessory digestive organs

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2
Q

alimentary canal

A

continuous muscular digestive system

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3
Q

organs of alimentary canal

A

mouth, pharynx, esophagus, stomach, small/large intestine, and anus

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4
Q

accessory digestive organs

A

teeth, tongue, gallbladder, digestive glands. salivary glands, liver, pancreas

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5
Q

Digestive process

A

ingestion, propulsion, digestion

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6
Q

ingestion

A

taking food into digestive tract

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7
Q

propulsion

A

swallowing and peristalsis

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8
Q

mechanical digestion

A

chewing, churning food in stomach, segmentation, mixes food with digestive jucies

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9
Q

segmentation

A

rhythmic local constrictions of intestine

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10
Q

chemical digestion

A

food molecules are broken down by enzymes secreted by various glands

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11
Q

where does chemical digestion begin an end

A

begin in mouth, end in SI

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12
Q

absorption

A

passage of digested products into blood or lymph, small intestines

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13
Q

defecation

A

elimination of indigestiable substances from the body

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14
Q

membranes of organs in abdominopelvic organs

A

visceral peritoneum and parietal

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15
Q

visceral peritoneum

A

covers external surface of digestive organs is continuous with the parietal peritoneum

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16
Q

parietal peritoneum

A

lines abdminopelvic cavity

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17
Q

peritoneal cavity

A

contains serous fluid

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18
Q

messentery

A

a double layer of peritoneum, provides route for bv, lymph, nerves, holds organs in place

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19
Q

largest mesentery

A

greater omentum

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20
Q

retroperitoneal organs

A

SAD PUCKER
suprarenal gland
aorta/ivs
dudoenum
pancreas
ureters
colon
kidney
esophagus
rectum

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21
Q

peritonitis

A

inflammation of peritoneum

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22
Q

peritonitis comes from

A

wound piercing abdomen, from perforating ulcer, burst appendix

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23
Q

4 layers of alimentary canal

A

mucosa, submucosa, muscularis externa, serosa

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24
Q

mucosa

A

inntermost layer, lines lumen

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25
Q

functions of mucosa

A

secretion of mucus, enzmes, hormones, absorption, protection against infection

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26
Q

3 sublayers of mucosa

A

epithelial, lamina propria, muscularis mucosae

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27
Q

epithelial lining

A

mucus secreting

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28
Q

lamina propria

A

loose CT, collagen, elastin, thick, MALT

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29
Q

muscularis mucosae

A

thin layer of smooth muscle cells, twitches to dislodge food

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30
Q

submucosa

A

dense CT with blood and lymph vessels, rich supply of elastic fibers and collagen, provides vascular network

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31
Q

muscularis externa

A

inner cirrcular layer of smooth muscle, outer layer of longitudinal muscle, peristalisis and segmentation

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32
Q

sphincter

A

when smooth muscle circular thickens

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33
Q

serosa

A

outermost protectice layer-visceral

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34
Q

what is serosa replaced by in esophagus

A

adventita

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35
Q

nerve suppy

A

submucosal nerve plexus, myenteric nerve plexus

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36
Q

submucosal nerve plexus

A

submucosa, controls activity of glands and smooth muscle in mucosa

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37
Q

myenteric nerve plexus

A

b/w circular and longitudinal smooth msucles, controls GI tract mobility

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38
Q

how are nerve plexus linked

A

afferent visceral nerves, efferent sym and para ANS

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39
Q

parasympathetic nerves control what in the digestive system

A

peristalsis and segmentation

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40
Q

Mouth

A

oral cavity, lined with stratified squamous, tongue and salivary glands

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41
Q

tongue

A

grips food, mixes it with salivia, compacts food into bolus, pushes it into pharynx, held in place by lingual frenulum

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42
Q

salivary glands

A

secrete saliva, extrinsic and intrinsic glands

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43
Q

extrinsic salivary glands

A

produce a majority of saliva, parotid, submandibular, sublingual, located outside oral cavity

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44
Q

intrinsic salivary glands

A

scattered throughout mucosa

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45
Q

salivary gland cells

A

serous, mucous, partoid gland, submandibular, intrinsic, sublingual

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46
Q

serous gland cells

A

watery fluid full of enzymes

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47
Q

mucous gland cells

A

stringy viscous fluid

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48
Q

parotid gland cells

A

serous

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49
Q

submandibular gland cess

A

serous and mucus

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50
Q

intrinsic gland cells

A

serous and mucus

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51
Q

sublingual cells

A

mucous

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52
Q

Saliva

A

mostly water, slightly acidic, produce 1 liter a day

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53
Q

parts of saliva

A

ions, amylase, proteins, lysozymes, IgA, metabolic wastes

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54
Q

what is saliva controlled by

A

ANS

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55
Q

Pharynx

A

stratified squamous epithelium, mucus producing glands, constrictor muscles propels food into esophagus

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56
Q

esophagus

A

normally collapsed

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57
Q

esophagus hiatus

A

esophagus pierces diaphragm here

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58
Q

cardiac orifice

A

where esophagus joins stomach

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59
Q

cardiac sphincter

A

gastroesophageal sphincter

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60
Q

stages of food going down esophagus

A
  1. Buccal Phase
  2. Pharyngeal-esophageal phase begins
  3. Pharyngeal phase 2
  4. Pharyngeal phase 3
  5. Pharyngeal phase 4
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61
Q

Buccal Phase

A

upper esophageal sphincter is contracted, tongue presses against the hard palate, forcing food bolus into the oropharynx

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62
Q

pharyngeal-esophageal phase begins

A

tongue blocks mouth, soft palate and uvula rise, epiglotitis blocks trachea, upper sphincter relaxes

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63
Q

pharyngeal-esophageal phase 2

A

constricter muscles of pharynx contract forcing food into the esophagus inferiorly, upper esophageal sphincter contracts after food enters

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64
Q

pharyngeal-esophageal phase 3

A

peristalsis moves food through esophagus to the stomach

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65
Q

pharyngeal-esophageal phase 4

A

spincter opens, food enters stomach, then closes again

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66
Q

stomach

A

temporary storage tank

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67
Q

food in stomach

A

creamy paste, chyme

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68
Q

stomach empty

A

holds 50 mls, mucosa and submucosa fold forming rugae

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69
Q

stomach at maximum

A

hold 4L or one gallon

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70
Q

pyloric sphincter

A

connects stomach to duodenum, controls stomach opening

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71
Q

lesser omentum

A

a mesentery connection of liver to lesser curvature

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72
Q

greater omentum

A

a mesentery running from greater curvature to coils of SI

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73
Q

oblique layer of stomach

A

allows churning and mixing of food

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74
Q

chemical digestion of proteins

A

by pepsin, only intiated in the stomach

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75
Q

renin in children

A

secreted by glands, breakdown milk protein casein

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76
Q

Gastric secretions

A

mucosa makes 3L of gastirc juice a day

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77
Q

increase of gland activity

A

vagus, parasympatheitc

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78
Q

decrease gastric gland activity

A

sympathetic nervous system

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79
Q

stomach lining

A

simple columnar epithelium-goblet cells and gastric puts

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80
Q

goblet cells of stomach

A

produce productive alkaline mucus

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81
Q

gastric pits

A

lead to glands, produce gastric juice, goblet cells

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82
Q

gastric glands

A

in cardiac and pylorus, secrete mucus

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83
Q

gastic glands in pyloric antrum

A

secrete mucus and the hormone gastrin

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84
Q

gastric glands in fundus and body secrete

A

mucus, HCL, enzymes, gastrin

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85
Q

cells of gastric glands

A

mucous neck cells, parietal cells, cheif cells, enteroendocrine cells

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86
Q

mucous neck cells

A

produce acidic mucus, towards bottom of upper duct

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87
Q

parietal cells

A

secrete HCL and intrinsic factor, responsible for extreme acidity of stomach

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88
Q

What do parietal cells do?

A

activates pepsin, denatures protein, breaks down wall of plant foods, kills many bacteria

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89
Q

chief cells

A

secrete pepsinogen

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90
Q

enteroendocrine cells

A

secrete downwards, gastrin, serotonin, histamine, somatostatin

91
Q

gastrin

A

increases gastric gland activity, HCL production, increases motility, relaxes ileocecal valve, stimulates mass movements

92
Q

serotonin

A

contraction of SM

93
Q

histamine

A

activates parietal cells

94
Q

somatostatin

A

inhibits gastric secretion, motility, GI blood flow and absorption, gallbladder, and pancreatic activity

95
Q

flow of secretions from entereoendorcrine

A

lamina propria-blood system- digestive organs

96
Q

3 phases of gastric secretion

A

cephalic reflex phase
gastric phase
intesitnal phase

97
Q

cephalic reflex phase

A

lasts a few minutes, occurs before food enters stomach, trigger by aroma, taste, sight or though of food

98
Q

steps of cephalic phase

A

gustatory and olfacotry receptors-impulses-hypothalamus-vagal nuclei-vagus nerve-stomach glands

99
Q

gastric phase

A

lasts 3-4 hours, provides 2/3 juice peptides and low acidity activates gastric EE cells

100
Q

stimuli of gastric phase

A

distension-activates stretch receptors-vagsvegal reflex-stimulares gastric glands

101
Q

intestinal phase

A

excitatory and inhibitory phase

102
Q

excitatory phase

A

as chime enters duodenum the intestinal mucosa releases intestinal gastrin that stimulates gastric glands

103
Q

inhibitory phase

A

a duodenum distends the enterogastric reflex is trigged, this puts brakes on the system
inhibit the vagal nuclei

104
Q

what does the inhibitory phase activates

A

the symphathetic nervous system that slows down digestion and release of enterogasterons from EE cells that all inhibit secretion

105
Q

how symphatetic nervous system slows down digestion

A

pyloric sphincter tightens, decrease food entry into duodenum, gastric secretion decreases

106
Q

secretin

A

stimulates alkaline pancreatic juice production and liver to produce bile

107
Q

CCK

A

stimulate enzyme rich pancreatic juice production, contraction of the gallbladder (stores bile)

108
Q

VIP

A

vasoactive intestinal peptide, dilates intestinal capillaries, inhibit HCL production

109
Q

enterogasterones

A

secretin, CCK, VIP

110
Q

where does peristalsis begin

A

at cardiac sphincter, as descends get more powerful

111
Q

steps of gastric contractile activity

A
  1. Propulsion
    2.Grinding
  2. Retropulsion
112
Q

propulsion

A

perstalic waves move from fundus towards pylorus

113
Q

grinding

A

most vigorus occur near pylorus, each wave at pylorus squirts 3 MLS of chyme into duodenum, waves occur 3 times/min

114
Q

retropulsion

A

perstitaic wave closes pyloric valve forcing contents of pylorus back into the stomach

115
Q

what is the rhythm of the stomach set by

A

pacemaker cells in longitudinal SM, intersital cells of Cajal
only when food in stomach, generate subthreshold depolarization waves

116
Q

gastric emptying

A

empties 4 hrs after meal, fluid moves fast solid moves slower

117
Q

small intestine

A

major digestive organ, longest part of canal (20 ft long)
duodenum, jejunum, ileum

118
Q

duodenum

A

10 inches long, curves around head of pancreas
hepatopancreatic ampulla
hepatopancreatic sphincter

119
Q

hepatopancreatic ampulla

A

bile duct and pancreatic duct unite

120
Q

hepatopancreatic sphicter (oddi)

A

empty of fluids controlled by this

121
Q

jejunum

A

8ft long, coiled in lower abdominal cavity, suspended by mesentery

122
Q

ileum

A

12 ft long, coiled, suspended by mesenetery, joins LI at ileocecal valve

123
Q

primary function of ileum

A

reabsorb bile salts

124
Q

plicae circularis

A

circular folds of mucosa and submucosa

125
Q

anatomy that increases surface area to maximize absorption

A

pilcae circularis, villi, microvilli, enterocytes, core of villus, lacteal

126
Q

villi

A

finger like projections on mucosa

127
Q

microvilli

A

tiny projections on epithelial cells of villi, brush border

128
Q

enterocytes

A

absorptive columnar cells that contain digestive enzymes

129
Q

core of villus

A

dense capillary bed and lacteal

130
Q

lacteal

A

where the breakdown of food enters

131
Q

5 cells on the villi and in crypts

A

enterocytes, goblet cells, enteroendocrine, paneth, stem cells

132
Q

enterocytes on the epithelial

A

mostly secretory

133
Q

enterocytes of the crypts

A

mostly secretory

134
Q

goblet cells

A

villi and crypt, secrete mucos

135
Q

enteroendocrine

A

entrogastrones

136
Q

paneth

A

deep in crypts, release lysozyme to destroy bacteria

137
Q

how often is the epithelium of the villi replaced

A

3-6 days

138
Q

peyers patches

A

submucosa aggregated lymphoid tissue, ileum

139
Q

intestinal juice

A

1-2 L.day, mostly water, some mucus, few enzymes

140
Q

what is the production of intestinal juice stimulated by

A

distension of intestinal mucosa by acidic chyme

141
Q

liver

A

largest gland, located under diaphragm

142
Q

function of liver

A

make bile and export it to the duodenum via the gallbladder, detoxifies

143
Q

how is the liver attached to the stomach

A

via lesser omentum

144
Q

liver lobules

A

hexagonal units, made of radiating paltes of heptocytes

145
Q

portal triad

A

corner of lobule, branch of hepatic artery ,portal vein, bile duct

146
Q

liver sinusoids

A

between hepatocyte plates, empty into central vein, drain blood from liver into IVC

147
Q

Kupffer cells

A

macrophages in sinusoids

148
Q

hepatocytes

A

in liver, produce bile, process nutrients, store glycogen, stores fat-soluble vitamins, detoxifies blood

149
Q

canaliculi

A

in the liver, bile flows through the small canals to bile ducts

150
Q

bile

A

yellow-green alkaline sol

151
Q

what does bile contain

A

bile salts. pigment, triglycerides, cholesterol, phospholipids

152
Q

What does bile help with

A

fat and cholesterol absoption

153
Q

how is bile disposed

A

most in the feces but bile salts are recycled via enterohepatic circulation

154
Q

how are bile salts absorbed

A

through the ileum into blood and transported back to liver

155
Q

bile pigments

A

yellowish bilrubin, made from degraded hemoglobin in the blood and delivered to the liver

156
Q

bilirubin

A

broken down by small intestine by bacteria to urobinogen which is oxidized to stercoblin which is brown

157
Q

gallbladder

A

stores bile and concetrates it, expels bile into cystic duct, flows into bile duct

158
Q

what is the stimulus of contraction of gallbladder?

A

CCK, released from intestine when fatty chyme enters duodenum, CCK stimulates secretion of pancreatic juice, relaxes hepatopancreatic sphincter

159
Q

Pancreas

A

located below the stomach, endocrine and exocrine function

160
Q

endocrine pancreas function

A

islets/islets of langerhans release insulin and glucagons

161
Q

exocrine pancreas function

A

acinar cells which produce enzymes

162
Q

enzymes in pancreatic juice

A

typsinogen, procarboxypeptidase, chymotrysinogen, amylase, lipase, nucleases

163
Q

typsinogen

A

enzyme activation to trypsin

164
Q

procarboxypeptidas

A

to carboxypeptidase, chop carboxyl group off

165
Q

chymotrysinogen

A

to chymotrypsin, for protein digestion

166
Q

amylase

A

starch, small intestine

167
Q

lipase

A

fats, smaller fats

168
Q

nucleases

A

nucleic acids, deoxyribonuclease, ribonuclease

169
Q

regulation of pancreatic secretion

A

parasympathetic, intestinal hormones

170
Q

intestinal hormones

A

secretin, cck

171
Q

secretin

A

targets duct cells, release of bicarbonate rich pancreatic juice

172
Q

CCK

A

stimulae acini to release enzyme-rich pancreatic juice

173
Q

segmentation

A

thoroughly mixes chyme with bile, pancreatic, and intestinal juices

174
Q

pacemakers in duodenum

A

depolarize 12-14 times/min

175
Q

pacemaker in ileum

A

depolarize 8-9 times/min

176
Q

perstalisis

A

occurs only after nutrients are absorbed

177
Q

what is intestinal contraction coordinated by?

A

enteric neurons

178
Q

digestion of starch

A

salivary amylase, pancreatic amylase, brush border enzymes

179
Q

salivary enzymes

A

splits starch into oligosaccharides, in mouth

180
Q

pancreatic amylase

A

breaks down startch and oligosaccharides into oligo and disaccharides, SI

181
Q

brush border enzymes in SI

A

dextrinase and glucoamylase, maltase, sucrase, lactase, glucose and galactose, fructose

182
Q

dextrinase and glucoamylase

A

break down oligosaccharides and disaccharadies into mono

183
Q

maltase, sucrase, lactase

A

break down maltose, sucrose, lactose

184
Q

glucose and falactose

A

transported across apical surface of the enterocyte by secondary active transport using sodium

185
Q

fructose

A

enters enterocytes by facilitated diffusion

186
Q

digestion of proteins

A

pepsin, trypsin and chymotrypsin, carboxypeptidase, brush border enzymes, dipepridase, trypsin and chymotrysin

187
Q

pepsin in stomach

A

cleaves peptide bonds when it sets into amino acid tyrosine and phenylalanine

188
Q

trypsin and chymotrypsin in small intestine

A

cleave proteins into smaller peptides

189
Q

carboxypeptisdase

A

cleaves off one amino acid at a time from the carboxyl end

190
Q

brush border enzymes for proteins

A

cleave off one amino acid at a time from both the carboxyl end and amino end

191
Q

dipeptidase

A

cleave dipetides

192
Q

trypsin and chymotrysin

A

cleave internal parts of protein

193
Q

Digestion of fats

A

bile salts, pancreatic lipase, lingual lipase, gastric lipase

194
Q

bile salts for digestion of fats

A

amphipahtic and insert themselves into the fat globules repelling them from each other

195
Q

pancreatic lipase

A

now breaks apart triglyceride molecules, producing 2 fatty acids and monogluceride

196
Q

lingual lipase

A

mouth breakdown of fats

197
Q

gastric lipase

A

stomach breakdown of fats

198
Q

fat globule breakdown in small intestine

A

emulsification
digestion
micelle formation
diffusion
chylumicron formation
chylomicron transport

199
Q

emulsification

A

bile salts in duodenum break larger fats into smaller

200
Q

digestion

A

pancreatic lipase hydrolyze trigylcerides,yielding monoglycerides and free fatty acids

201
Q

micelle formation

A

free farry acids and monoglycerides assble with bile salts forming micelles, ferry contents into enterocytes

202
Q

diffusion

A

fatty acids and mono diffuse from micelles into enterocytes

203
Q

chylomicron formation

A

fatty acids and mon are recombined and packaged with other fatty acids and proteins to form chylomicrons

204
Q

chylomicron transported

A

extruded by exocytosis, enter lacteals

205
Q

digestion of nucleic acids

A

ribonucleases, deoxyribonucleases, nucleotides and phosphastases

206
Q

ribonucleases and deoxyribonucleases

A

in pancreatic juice that digest nucleic acids into nucleotides

207
Q

nucleotidases and phosphates

A

in brush border, then break nulceotides into nitrogen containing base, pentose sugar, phosphate ion

208
Q

absorption

A

almost all food and 80% of fluid is absorbed int SI

209
Q

large intestine

A

ileocecal valce to anus

210
Q

function of large intestine

A

absorb excess H2O and expel waste

211
Q

antaomy of large intestine

A

teniae coli, haustra, epiploci appendages, cecum, colon, rectum

212
Q

teniae coli

A

long. mucle of large intestine

213
Q

haustra

A

long mucles is reduced to 3 bands and form this

214
Q

cecum

A

blind pouch, begin to pull back H2O, attached is appendix

215
Q

colon

A

ascending, transvers, descending, sigmoid

216
Q

rectum

A

rectal valvse, anal canal

217
Q

anal canal

A

largest part of GI tract, 3 cm long

218
Q

interal anal sphincter

A

involuntary, SM

219
Q

external anal sphincter

A

voluntary, skeletal muscle

220
Q

cells of LI

A

simple columnar epithelia secreting a lot of mucus for lubrication

221
Q

digestive process in LI

A

bacteria ferment soem indigestiable carbohydrates releasing gas, no further food breakdown

222
Q

gases that are released

A

H2, N2, dimethyl, CH4, CO2

223
Q

motility

A

mass movements are long powerful

224
Q

defecation

A

occurs when rectal wall is stretched by fecal contents