Digestive System Flashcards
1
Q
Organs of digestive system
A
alimentary canal and accessory digestive organs
2
Q
alimentary canal
A
continuous muscular digestive system
3
Q
organs of alimentary canal
A
mouth, pharynx, esophagus, stomach, small/large intestine, and anus
4
Q
accessory digestive organs
A
teeth, tongue, gallbladder, digestive glands. salivary glands, liver, pancreas
5
Q
Digestive process
A
ingestion, propulsion, digestion
6
Q
ingestion
A
taking food into digestive tract
7
Q
propulsion
A
swallowing and peristalsis
8
Q
mechanical digestion
A
chewing, churning food in stomach, segmentation, mixes food with digestive jucies
9
Q
segmentation
A
rhythmic local constrictions of intestine
10
Q
chemical digestion
A
food molecules are broken down by enzymes secreted by various glands
11
Q
where does chemical digestion begin an end
A
begin in mouth, end in SI
12
Q
absorption
A
passage of digested products into blood or lymph, small intestines
13
Q
defecation
A
elimination of indigestiable substances from the body
14
Q
membranes of organs in abdominopelvic organs
A
visceral peritoneum and parietal
15
Q
visceral peritoneum
A
covers external surface of digestive organs is continuous with the parietal peritoneum
16
Q
parietal peritoneum
A
lines abdminopelvic cavity
17
Q
peritoneal cavity
A
contains serous fluid
18
Q
messentery
A
a double layer of peritoneum, provides route for bv, lymph, nerves, holds organs in place
19
Q
largest mesentery
A
greater omentum
20
Q
retroperitoneal organs
A
SAD PUCKER
suprarenal gland
aorta/ivs
dudoenum
pancreas
ureters
colon
kidney
esophagus
rectum
21
Q
peritonitis
A
inflammation of peritoneum
22
Q
peritonitis comes from
A
wound piercing abdomen, from perforating ulcer, burst appendix
23
Q
4 layers of alimentary canal
A
mucosa, submucosa, muscularis externa, serosa
24
Q
mucosa
A
inntermost layer, lines lumen
25
functions of mucosa
secretion of mucus, enzmes, hormones, absorption, protection against infection
26
3 sublayers of mucosa
epithelial, lamina propria, muscularis mucosae
27
epithelial lining
mucus secreting
28
lamina propria
loose CT, collagen, elastin, thick, MALT
29
muscularis mucosae
thin layer of smooth muscle cells, twitches to dislodge food
30
submucosa
dense CT with blood and lymph vessels, rich supply of elastic fibers and collagen, provides vascular network
31
muscularis externa
inner cirrcular layer of smooth muscle, outer layer of longitudinal muscle, peristalisis and segmentation
32
sphincter
when smooth muscle circular thickens
33
serosa
outermost protectice layer-visceral
34
what is serosa replaced by in esophagus
adventita
35
nerve suppy
submucosal nerve plexus, myenteric nerve plexus
36
submucosal nerve plexus
submucosa, controls activity of glands and smooth muscle in mucosa
37
myenteric nerve plexus
b/w circular and longitudinal smooth msucles, controls GI tract mobility
38
how are nerve plexus linked
afferent visceral nerves, efferent sym and para ANS
39
parasympathetic nerves control what in the digestive system
peristalsis and segmentation
40
Mouth
oral cavity, lined with stratified squamous, tongue and salivary glands
41
tongue
grips food, mixes it with salivia, compacts food into bolus, pushes it into pharynx, held in place by lingual frenulum
42
salivary glands
secrete saliva, extrinsic and intrinsic glands
43
extrinsic salivary glands
produce a majority of saliva, parotid, submandibular, sublingual, located outside oral cavity
44
intrinsic salivary glands
scattered throughout mucosa
45
salivary gland cells
serous, mucous, partoid gland, submandibular, intrinsic, sublingual
46
serous gland cells
watery fluid full of enzymes
47
mucous gland cells
stringy viscous fluid
48
parotid gland cells
serous
49
submandibular gland cess
serous and mucus
50
intrinsic gland cells
serous and mucus
51
sublingual cells
mucous
52
Saliva
mostly water, slightly acidic, produce 1 liter a day
53
parts of saliva
ions, amylase, proteins, lysozymes, IgA, metabolic wastes
54
what is saliva controlled by
ANS
55
Pharynx
stratified squamous epithelium, mucus producing glands, constrictor muscles propels food into esophagus
56
esophagus
normally collapsed
57
esophagus hiatus
esophagus pierces diaphragm here
58
cardiac orifice
where esophagus joins stomach
59
cardiac sphincter
gastroesophageal sphincter
60
stages of food going down esophagus
1. Buccal Phase
2. Pharyngeal-esophageal phase begins
3. Pharyngeal phase 2
4. Pharyngeal phase 3
5. Pharyngeal phase 4
61
Buccal Phase
upper esophageal sphincter is contracted, tongue presses against the hard palate, forcing food bolus into the oropharynx
62
pharyngeal-esophageal phase begins
tongue blocks mouth, soft palate and uvula rise, epiglotitis blocks trachea, upper sphincter relaxes
63
pharyngeal-esophageal phase 2
constricter muscles of pharynx contract forcing food into the esophagus inferiorly, upper esophageal sphincter contracts after food enters
64
pharyngeal-esophageal phase 3
peristalsis moves food through esophagus to the stomach
65
pharyngeal-esophageal phase 4
spincter opens, food enters stomach, then closes again
66
stomach
temporary storage tank
67
food in stomach
creamy paste, chyme
68
stomach empty
holds 50 mls, mucosa and submucosa fold forming rugae
69
stomach at maximum
hold 4L or one gallon
70
pyloric sphincter
connects stomach to duodenum, controls stomach opening
71
lesser omentum
a mesentery connection of liver to lesser curvature
72
greater omentum
a mesentery running from greater curvature to coils of SI
73
oblique layer of stomach
allows churning and mixing of food
74
chemical digestion of proteins
by pepsin, only intiated in the stomach
75
renin in children
secreted by glands, breakdown milk protein casein
76
Gastric secretions
mucosa makes 3L of gastirc juice a day
77
increase of gland activity
vagus, parasympatheitc
78
decrease gastric gland activity
sympathetic nervous system
79
stomach lining
simple columnar epithelium-goblet cells and gastric puts
80
goblet cells of stomach
produce productive alkaline mucus
81
gastric pits
lead to glands, produce gastric juice, goblet cells
82
gastric glands
in cardiac and pylorus, secrete mucus
83
gastic glands in pyloric antrum
secrete mucus and the hormone gastrin
84
gastric glands in fundus and body secrete
mucus, HCL, enzymes, gastrin
85
cells of gastric glands
mucous neck cells, parietal cells, cheif cells, enteroendocrine cells
86
mucous neck cells
produce acidic mucus, towards bottom of upper duct
87
parietal cells
secrete HCL and intrinsic factor, responsible for extreme acidity of stomach
88
What do parietal cells do?
activates pepsin, denatures protein, breaks down wall of plant foods, kills many bacteria
89
chief cells
secrete pepsinogen
90
enteroendocrine cells
secrete downwards, gastrin, serotonin, histamine, somatostatin
91
gastrin
increases gastric gland activity, HCL production, increases motility, relaxes ileocecal valve, stimulates mass movements
92
serotonin
contraction of SM
93
histamine
activates parietal cells
94
somatostatin
inhibits gastric secretion, motility, GI blood flow and absorption, gallbladder, and pancreatic activity
95
flow of secretions from entereoendorcrine
lamina propria-blood system- digestive organs
96
3 phases of gastric secretion
cephalic reflex phase
gastric phase
intesitnal phase
97
cephalic reflex phase
lasts a few minutes, occurs before food enters stomach, trigger by aroma, taste, sight or though of food
98
steps of cephalic phase
gustatory and olfacotry receptors-impulses-hypothalamus-vagal nuclei-vagus nerve-stomach glands
99
gastric phase
lasts 3-4 hours, provides 2/3 juice peptides and low acidity activates gastric EE cells
100
stimuli of gastric phase
distension-activates stretch receptors-vagsvegal reflex-stimulares gastric glands
101
intestinal phase
excitatory and inhibitory phase
102
excitatory phase
as chime enters duodenum the intestinal mucosa releases intestinal gastrin that stimulates gastric glands
103
inhibitory phase
a duodenum distends the enterogastric reflex is trigged, this puts brakes on the system
inhibit the vagal nuclei
104
what does the inhibitory phase activates
the symphathetic nervous system that slows down digestion and release of enterogasterons from EE cells that all inhibit secretion
105
how symphatetic nervous system slows down digestion
pyloric sphincter tightens, decrease food entry into duodenum, gastric secretion decreases
106
secretin
stimulates alkaline pancreatic juice production and liver to produce bile
107
CCK
stimulate enzyme rich pancreatic juice production, contraction of the gallbladder (stores bile)
108
VIP
vasoactive intestinal peptide, dilates intestinal capillaries, inhibit HCL production
109
enterogasterones
secretin, CCK, VIP
110
where does peristalsis begin
at cardiac sphincter, as descends get more powerful
111
steps of gastric contractile activity
1. Propulsion
2.Grinding
3. Retropulsion
112
propulsion
perstalic waves move from fundus towards pylorus
113
grinding
most vigorus occur near pylorus, each wave at pylorus squirts 3 MLS of chyme into duodenum, waves occur 3 times/min
114
retropulsion
perstitaic wave closes pyloric valve forcing contents of pylorus back into the stomach
115
what is the rhythm of the stomach set by
pacemaker cells in longitudinal SM, intersital cells of Cajal
only when food in stomach, generate subthreshold depolarization waves
116
gastric emptying
empties 4 hrs after meal, fluid moves fast solid moves slower
117
small intestine
major digestive organ, longest part of canal (20 ft long)
duodenum, jejunum, ileum
118
duodenum
10 inches long, curves around head of pancreas
hepatopancreatic ampulla
hepatopancreatic sphincter
119
hepatopancreatic ampulla
bile duct and pancreatic duct unite
120
hepatopancreatic sphicter (oddi)
empty of fluids controlled by this
121
jejunum
8ft long, coiled in lower abdominal cavity, suspended by mesentery
122
ileum
12 ft long, coiled, suspended by mesenetery, joins LI at ileocecal valve
123
primary function of ileum
reabsorb bile salts
124
plicae circularis
circular folds of mucosa and submucosa
125
anatomy that increases surface area to maximize absorption
pilcae circularis, villi, microvilli, enterocytes, core of villus, lacteal
126
villi
finger like projections on mucosa
127
microvilli
tiny projections on epithelial cells of villi, brush border
128
enterocytes
absorptive columnar cells that contain digestive enzymes
129
core of villus
dense capillary bed and lacteal
130
lacteal
where the breakdown of food enters
131
5 cells on the villi and in crypts
enterocytes, goblet cells, enteroendocrine, paneth, stem cells
132
enterocytes on the epithelial
mostly secretory
133
enterocytes of the crypts
mostly secretory
134
goblet cells
villi and crypt, secrete mucos
135
enteroendocrine
entrogastrones
136
paneth
deep in crypts, release lysozyme to destroy bacteria
137
how often is the epithelium of the villi replaced
3-6 days
138
peyers patches
submucosa aggregated lymphoid tissue, ileum
139
intestinal juice
1-2 L.day, mostly water, some mucus, few enzymes
140
what is the production of intestinal juice stimulated by
distension of intestinal mucosa by acidic chyme
141
liver
largest gland, located under diaphragm
142
function of liver
make bile and export it to the duodenum via the gallbladder, detoxifies
143
how is the liver attached to the stomach
via lesser omentum
144
liver lobules
hexagonal units, made of radiating paltes of heptocytes
145
portal triad
corner of lobule, branch of hepatic artery ,portal vein, bile duct
146
liver sinusoids
between hepatocyte plates, empty into central vein, drain blood from liver into IVC
147
Kupffer cells
macrophages in sinusoids
148
hepatocytes
in liver, produce bile, process nutrients, store glycogen, stores fat-soluble vitamins, detoxifies blood
149
canaliculi
in the liver, bile flows through the small canals to bile ducts
150
bile
yellow-green alkaline sol
151
what does bile contain
bile salts. pigment, triglycerides, cholesterol, phospholipids
152
What does bile help with
fat and cholesterol absoption
153
how is bile disposed
most in the feces but bile salts are recycled via enterohepatic circulation
154
how are bile salts absorbed
through the ileum into blood and transported back to liver
155
bile pigments
yellowish bilrubin, made from degraded hemoglobin in the blood and delivered to the liver
156
bilirubin
broken down by small intestine by bacteria to urobinogen which is oxidized to stercoblin which is brown
157
gallbladder
stores bile and concetrates it, expels bile into cystic duct, flows into bile duct
158
what is the stimulus of contraction of gallbladder?
CCK, released from intestine when fatty chyme enters duodenum, CCK stimulates secretion of pancreatic juice, relaxes hepatopancreatic sphincter
159
Pancreas
located below the stomach, endocrine and exocrine function
160
endocrine pancreas function
islets/islets of langerhans release insulin and glucagons
161
exocrine pancreas function
acinar cells which produce enzymes
162
enzymes in pancreatic juice
typsinogen, procarboxypeptidase, chymotrysinogen, amylase, lipase, nucleases
163
typsinogen
enzyme activation to trypsin
164
procarboxypeptidas
to carboxypeptidase, chop carboxyl group off
165
chymotrysinogen
to chymotrypsin, for protein digestion
166
amylase
starch, small intestine
167
lipase
fats, smaller fats
168
nucleases
nucleic acids, deoxyribonuclease, ribonuclease
169
regulation of pancreatic secretion
parasympathetic, intestinal hormones
170
intestinal hormones
secretin, cck
171
secretin
targets duct cells, release of bicarbonate rich pancreatic juice
172
CCK
stimulae acini to release enzyme-rich pancreatic juice
173
segmentation
thoroughly mixes chyme with bile, pancreatic, and intestinal juices
174
pacemakers in duodenum
depolarize 12-14 times/min
175
pacemaker in ileum
depolarize 8-9 times/min
176
perstalisis
occurs only after nutrients are absorbed
177
what is intestinal contraction coordinated by?
enteric neurons
178
digestion of starch
salivary amylase, pancreatic amylase, brush border enzymes
179
salivary enzymes
splits starch into oligosaccharides, in mouth
180
pancreatic amylase
breaks down startch and oligosaccharides into oligo and disaccharides, SI
181
brush border enzymes in SI
dextrinase and glucoamylase, maltase, sucrase, lactase, glucose and galactose, fructose
182
dextrinase and glucoamylase
break down oligosaccharides and disaccharadies into mono
183
maltase, sucrase, lactase
break down maltose, sucrose, lactose
184
glucose and falactose
transported across apical surface of the enterocyte by secondary active transport using sodium
185
fructose
enters enterocytes by facilitated diffusion
186
digestion of proteins
pepsin, trypsin and chymotrypsin, carboxypeptidase, brush border enzymes, dipepridase, trypsin and chymotrysin
187
pepsin in stomach
cleaves peptide bonds when it sets into amino acid tyrosine and phenylalanine
188
trypsin and chymotrypsin in small intestine
cleave proteins into smaller peptides
189
carboxypeptisdase
cleaves off one amino acid at a time from the carboxyl end
190
brush border enzymes for proteins
cleave off one amino acid at a time from both the carboxyl end and amino end
191
dipeptidase
cleave dipetides
192
trypsin and chymotrysin
cleave internal parts of protein
193
Digestion of fats
bile salts, pancreatic lipase, lingual lipase, gastric lipase
194
bile salts for digestion of fats
amphipahtic and insert themselves into the fat globules repelling them from each other
195
pancreatic lipase
now breaks apart triglyceride molecules, producing 2 fatty acids and monogluceride
196
lingual lipase
mouth breakdown of fats
197
gastric lipase
stomach breakdown of fats
198
fat globule breakdown in small intestine
emulsification
digestion
micelle formation
diffusion
chylumicron formation
chylomicron transport
199
emulsification
bile salts in duodenum break larger fats into smaller
200
digestion
pancreatic lipase hydrolyze trigylcerides,yielding monoglycerides and free fatty acids
201
micelle formation
free farry acids and monoglycerides assble with bile salts forming micelles, ferry contents into enterocytes
202
diffusion
fatty acids and mono diffuse from micelles into enterocytes
203
chylomicron formation
fatty acids and mon are recombined and packaged with other fatty acids and proteins to form chylomicrons
204
chylomicron transported
extruded by exocytosis, enter lacteals
205
digestion of nucleic acids
ribonucleases, deoxyribonucleases, nucleotides and phosphastases
206
ribonucleases and deoxyribonucleases
in pancreatic juice that digest nucleic acids into nucleotides
207
nucleotidases and phosphates
in brush border, then break nulceotides into nitrogen containing base, pentose sugar, phosphate ion
208
absorption
almost all food and 80% of fluid is absorbed int SI
209
large intestine
ileocecal valce to anus
210
function of large intestine
absorb excess H2O and expel waste
211
antaomy of large intestine
teniae coli, haustra, epiploci appendages, cecum, colon, rectum
212
teniae coli
long. mucle of large intestine
213
haustra
long mucles is reduced to 3 bands and form this
214
cecum
blind pouch, begin to pull back H2O, attached is appendix
215
colon
ascending, transvers, descending, sigmoid
216
rectum
rectal valvse, anal canal
217
anal canal
largest part of GI tract, 3 cm long
218
interal anal sphincter
involuntary, SM
219
external anal sphincter
voluntary, skeletal muscle
220
cells of LI
simple columnar epithelia secreting a lot of mucus for lubrication
221
digestive process in LI
bacteria ferment soem indigestiable carbohydrates releasing gas, no further food breakdown
222
gases that are released
H2, N2, dimethyl, CH4, CO2
223
motility
mass movements are long powerful
224
defecation
occurs when rectal wall is stretched by fecal contents
