Unit 6: Digestive System Flashcards
1
Q
2 major divisions
A
- digestive tract
- accessory glands and structures
2
Q
digestie system length
A
15 ft but 30 when dissected
3
Q
general functions
A
- motility
- secretion
- digestion
- absorption
- immunological
4
Q
the digestive system is ?
A
unidirectional
5
Q
volume absorbed by the small intestine per day
A
9000 mL
6
Q
sources of volume absorbed by the small intestine per day
A
- ingested
- secreted from plasma
7
Q
volume of food eaten per day
A
1250 g
8
Q
volume of fluid drank per day
A
1250 mL
9
Q
sources secreted from the plasma
A
- saliva
- gastric juice
- pancreatic juice
- bile
- intestinal juice
10
Q
tissue types in the digestive tract wall
A
- epithelium
- lymphoid tissue
- connective tissue
- nerve plexuses
- smooth muscle
11
Q
digestive tract wall
A
- mesentery
- serosa
- submucosa
- muscularis externa
- mucosa
- myenteric plexus
- submucosal plexus
12
Q
digestive tract wall nerves
A
- myenteric plexus
- submucosal plexus
13
Q
mesentery
A
14
Q
serosa
A
15
Q
submucosa
A
16
Q
muscularis externa layers
A
- outer longitudinal muscle
- inner circular muscle
17
Q
mucosa
A
18
Q
myenteric plexus
A
19
Q
submucosal plexus
A
20
Q
outer longitudinal muscle
A
21
Q
inner circular muscle
A
22
Q
the serosa is continuous with the ?
A
mesentery
23
Q
outer longitudinal muscle versus inner circular muscle
A
- outer muscle shortens lengthens
- inner circular muscle contracts
24
Q
stomach anatomy
A
- abdominal esophagus
- cardia
- cardial notch
- fundus
- lesser curvature
- pyloric orifice
- duodenum
- pyloric constriction
- pyloric sphincter
- pyloric canal
- pyloric antrum
- body
- greater curvature
- fundus
25
stomach cardia
26
stomach fundus
27
stomach pyloric orifice
28
stomach pyloric constriction
29
stomach pyloric sphincter
30
stomach pyloric canal
31
stomach pyloric antrum
32
stomach body
33
stomach functions
- storage
- mixing
- digestion
34
where are interstitial cells of cajal located
fundus
35
interstitial cells of cajal
- pacemaker cells
- 3 per minute
36
in which region does major mixing in the stomach happen
pyloric
37
mucosal linings of the stomach
- oxyntic mucosa
- pyloric gland area
38
gastric gland definition
cells for gastric secretion
39
how much gastric juice is produced per day
2 liters
40
oxyntic mucosa
41
pyloric gland area
42
gastric pit
43
gastric glands
44
types of exocrine secretory cells
- exocrine cells
- mucous cells
- chief cells
- parietal cells
45
types of endocrine/paracrine secretory cells
- enterochromaffin-like (ECL) cells
- G cells
- D cells
46
mucous cell purpose
- produce alkaline mucus
- protects against enzymes
- neutralizes acidic content
47
chief cell purpose
- produce pepsinogen (enzyme precursor)
- protein digestion
48
parietal cell purpose
- hydrochloric acid
- activates pepsinogen for protein digestion
- produce intrinsic factor
- absorbs vitamins (mainly B12)
49
enterochromaffin-like (ECL) cell purpose
produce histamines that produce HCl for parietal cells
50
G cell purpose
- produce gastrin
- stimulate chief, parietal, and ECL cells
51
D cell purpose
- produce somatostatin
- inhibits parietal, ECL, and G cells
52
G cell location
pyloric gland area
53
D cell location
pyloric gland area
54
parietal cell location
oxyntic mucosa
55
chief cell location
oxyntic mucosa
56
mucous cell location
oxyntic mucosa
57
mucosal barrier function
protection of gastric mucosa
58
mucosal barrier
secretion of mucous and HCO3 by epithelial cells to form a barrier that protects stomach from low pH and digestion by pepsin
59
gastric mucosal barrier lines of defense to protect from self-injury
60
3 parts of the small intestine
- duodenum
- jejenum
- ileum
61
primary site of absorption
small intestine
62
villi definition and function
- tiny hair-like projections that line the inside of the small intestine
- increase surface area 10x to increase absorption
63
microvilli increase surface area by __x
20
64
duodenum
65
jejenum
66
ileum
67
types and function of membrane bound enzymes in villi
types:
- enteropeptidase
- disaccharidases
- aminopeptidases
function:
- carbohydrate and protein digestion
68
villi epithelial cell
69
villi central lacteal location and function
70
villi capillaries
71
large intestine parts
- appendix
- cecum
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
72
(large intestine) appendix
73
(large intestine) cecum
74
(large intestine) ascending colon
75
(large intestine) transverse colon
76
(large intestine) descending colon
77
(large intestine) sigmoid colon
78
(large intestine) rectum
79
gastrointestinal accessory glands
- salivary glands
- submandibular glands
- sublingual glands
- pancreatic secretions
80
salivary glands
- parotid gland
- parotid duct pierces buccinator and secretes a serous secretion
- produce amylase
81
where does the parotid duct drain
into cheek opposite maxillary 2nd molar (parotid papilla)
82
amylase
digestive enzyme
83
submandibular glands
- hook shaped with superficial and deep arms
- submandibular duct
- merges from deep part to open on sublingual papilla
- runs over lingual nerve
84
lingual frenum
85
sublingual fold
86
sublingual papilla
87
submandibular duct
88
submandibular gland
89
sublingual glands
- almond-shaped glands lateral to the submandibular duct
- sublingual duct drains into oral cavity via several minor ducts
90
sublingual gland
91
small ducts of sublingual gland
92
type of secretion produced by submandibular glands
mixed mucous and serous secretion
93
type of secretion produced by sublingual glands
mixed mucous and serous secretion (predominantly mucous)
94
pancreatic gland types
- exocrine
- endocrine
95
exocrine pancreatic secretions
- enzymes (proteolytic enzymes, pancreatic amylase, pancreatic lipase)
- bicarbonate
96
endocrine pancreatic secretions
- insulin
- glucagon
- hormones
97
exocrine pancreatic cells
- duct cells
- acinar cells
98
pancreas duct cell purpose
neutralize acid
99
pancreas acinar cell purpose
enzymes assist in digestion
100
liver is the ...
destination of absorbed materials
101
absorbed nutrient path
nutrients absorbed into blood --> hepatic portal vein --> liver
102
peristalsis definition
wave of contraction
103
basic electrical rhythm (peristalsis) definition
sets up a wave of contraction in the muscularis externa
104
segmentation
muscular activity that divides and mixes the chyme by alternating between backward and forward movement of the gastrointestinal tract (GI) contents
105
pacemaker cells of the stomach
interstitial cells of cajal
106
teniae coli
- 3 longitudinal bands of muscle
- scrunch to form haustra
107
haustra
pouches or sacs
108
what is mainly responsible for colonic motility
haustral contractions
109
haustral contraction characteristics
- slow
- nonpropulsive
110
what initiates haustral contractions
basic electrical rhythym
111
defecation reflex
1. feces move into and distend rectum, stimulating stretch receptors. receptors transmit signals along afferent fibers to spinal cord neurons
2. spinal reflex initiated (parasympathetic motor fibers stimulate contraction of the rectum and sigmoid colon and relaxation of the internal anal sphincter)
3. voluntary motor neurons inhibited when it is convenient to defecate allowing external anal sphincter to relax for feces to pass
*voluntary raising intra-abdominal pressure and relaxing external sphincter permits defecation
112
continence
defecation delayed by contraction of external sphincter
113
water movement across intestinal epithelium is ? to ions and solutes
secondary
114
transcellular
transportation of solutes by a cell through a cell
115
paracellular
transport of solutes that occurs in an intercellular pathway
116
transcellular and paracellular pathway function
transport mechanism for carbohydrates and protein across luminal and basolateral membranes
117
basolateral membrane
- the cell membrane at the basolateral (cell base) side of the cell
- faces adjacent cells and the underlying connective tissue
118
luminal membrane
the cell membrane which is oriented towards the lumen
119
apical membrane
the plasma membrane located at the apex of the epithelial cell
120
epithelial tight junctions
intercellular space that forms the continuous intercellular barrier between epithelial cells (separates tissue spaces and regulates selective movement of solutes across the epithelium)
121
where does the most absorption occur
duodenum and jejunum
122
for what material is absorption adjusted and why
- iron and calcium
- body only takes in what it needs
123
carbohydrate digestion goal
break down all disaccharides and complex carbohydrates into monosaccharides for absorption
124
carbohydrate polysaccharide composition
125
how are carbohydrate polysaccharides digested
- initially digested by amylase
- secondary digested at the brush border/microvilli on intestinal epithelial cells
126
amylase function
break carbohydrate polysaccharides into disaccharides
127
polysaccharide examples
- starch
- glycogen
128
disaccharide examples
- lactose
- maltose
- sucrose
129
monosaccharides examples
- galactose
- glucose
- fructose
130
from where is amylase secreted
- salivary glands
- pancreas
131
dietary carbohydrate examples
- lactose
- starch
- glycogen
- sucrose
132
how is lactose digested
- lactose is a disaccharide
- no amylase used, only brush border
- not digested in mouth or digestive tract lumen, only small intestine
133
how is sucrose digested
- sucrose is a disaccharide
- no amylase used, only brush border
- not digested in mouth or digestive tract lumen, only small intestine
134
how is starch digested
- starch is a polysaccharide
- with amylase and brush border
- digested in mouth, digestive tract lumen, and small intestine
135
how is glycogen digested
- glycogen is a polysaccharide
- with amylase and brush border
- digested in mouth, digestive tract lumen, and small intestine
136
SGLT1
- sodium-glucose cotransporter (SGLT)
- secondary active transport (against the concentration gradient but no ATP used since glucose/galactose cotransports with Na+)
- apical sodium and glucose/galactose move across cell membranes
137
how does glucose enter the luminal membrane
secondary active transport via SGLT1
138
how does galactose enter the luminal membrane
secondary active transport via SGLT1
139
how does fructose enter the luminal membrane
simple diffusion via GLUT-5
140
how does Na+ enter the luminal membrane
simple diffusion via SGLT1
141
GLUT-2
- facilitative diffusion
- transports dietary sugars, glucose, fructose and galactose across the basolateral membrane
142
how does glucose exit the basolateral membrane
facilitative diffusion via GLUT-2
143
how does galactose exit the basolateral membrane
facilitative diffusion via GLUT-2
144
how does fructose exit the basolateral membrane
facilitative diffusion via GLUT-2
145
diarrhea definition
passage of a highly fluid fecal matter
146
what does diarrhea cause
- dehydration
- loss of nutrient material (small intestine unable to absorb fluid extensively)
- metabolic acidosis
147
metabolic acidosis
buildup of acid in the body due to kidney disease or kidney failure
148
causes of diarrhea
- excessive small-intestinal mobility
- toxins of the bacterium vibrio cholera
- excess osmotically active particles
(eg lactase deficiency)
- anxiety
- illness
149
where does protein digestion begin
pyloric antrum
150
in which environment does pepsin work most effectively
an acidic one
151
HCl importance
converts pepsinogen into pepsin
152
what secretes pepsinogen
chief cells
153
what secretes HCl
parietal cells
154
pepsin function
breaks down dietary protein into large peptides and free amino acids
155
types of protein
- exogenous
- endogenous
156
exogenous protein
dietary protein
157
endogenous protein
- digestive enzymes
- sloughed epithelial cells
- leaked plasma proteins
158
how/where is protein digested
- digestive tract lumen (exogenous and endogenous proteins broken into small peptides and amino acids by pepsin and pancreatic proteolytic enzymes)
- brush border of small intestine epithelial cells and cytosol of epithelial cells (small peptides broken into amino acids by aminopeptidases and intracellular peptidases)
159
how do amino acids enter the luminal membrane
secondary active transport with Na+
160
how does Na+ enter the luminal membrane
facilitative diffusion
161
how does H+ exit the luminal membrane
secondary active transport with Na+ (H+ exits cell white Na+ enters cell)
162
how does H+ enter the luminal membrane
facilitated diffusion
163
how do small peptides enter the luminal membrane
tertiary active transport with H+
164
how do small peptides leave the basolateral membrane
- they don't
- small peptides are broken down into amino acids via intracellular peptidases
165
how do amino acids exit the basolateral membrane
facilitated diffusion
166
3 inactive proteolytic enzymes in the duodenum for protein digestion
- trypsinogen
- chymotrypsinogen
- procarboxypeptidase
167
how do inactive proteolytic enzymes for protein digestion enter the small intestine lumen
via the pancreatic duct
168
what does trypsinogen convert to
trypsin
169
what does chymptrypsinogen convert to
chymotrypsin
170
what does preocarboxypeptidase convert to
carboxypeptidase
171
what converts trypsinogen into trypsin
enterokinase
172
what secretes inactive proteolytic enzymes for protein digestion
acinar cells
173
what converts chymotrypsinogen into chymotrypsin
trypsin
174
what converts procarboxypeptidase into carboxypeptidase
chymotrypsin
175
trypsinogen must remain inactive within the ?
pancreas
176
mucus secretion function
protection
177
trypsin, chymotrypsin, carbozypeptidase function
attack active peptide and break them down into amino acids
178
what are triglycerides broken down into
- monoglyceride
- free fatty acids
179
what is a triglyceride
a type of fat
180
what breaks triglycerides down
lingual, gastric, and pancreatic lipases
181
lipase definition
a type of digestive enzyme that helps your body digest fats
182
how is fat absorption different from carbohydrate and protein absorption
fat is insoluble in water
183
micelle definition
- water-soluble particles
that can carry the end products of fat digestion within their lipid-soluble
interiors
- vehicle for carrying water-insoluble stances through watery luminal contents
184
fat digestion process (triglyceride droplet to central lacteal)
1. triglyceride droplet emulsified by bile salts
2. pancreatic lipase breaks droplet into monoglyceride and free fatty acids (insoluble in water)
3. bile salts envelop the fatty acids and monoglycerides to form micelles
4. micelles enter the luminal membrane
5. monoglycerides and fatty acids resynthesize in the cell to form triglycerides
6. triglycerides aggregate and are coated with lipoprotein to form chylomicrons (water soluble)
7. chylomicrons exit the basolateral membrane and enter the central lacteal via exocytosis
185
exocytosis
-the fusion of secretory vesicles with the plasma membrane
- results in the discharge of vesicle content into the extracellular space and the incorporation of new proteins and lipids into the plasma membrane
186
why do chylomicrons enter the central lacteal instead of capillaries
chylomicrons too big
187
central lacteal
- blood capillaries and special lymph capillaries, called lacteals, in the center of each villus
- fats and fat-soluble vitamins are absorbed by the lacteals
- filled with chyle
188
chyle
- a milky fluid consisting of fat droplets and lymph
- drains from the lacteals of the small intestine into the lymphatic system during digestion
189
how does the fat go from the central lacteal into the bloodstream
lacteal --> lymph vessel --> duct --> subclavian veins
190
how do micelles enter the luminal membrane
passive absorption
191
how are micelles water soluble
- have hydrophilic shells
- can dissolve water-insoluble (lipid-soluble) substances in their lipid-soluble cores
192
do micelles have a hydrophillic/phoblic core and shell?
193
cholecystokinin (CCK) function
stimulates contraction of gallbladder and relaxation of the sphincter of oddi
194
feedback loop of cholecystokinin (CCK) in digestion
195
?% of bile salts are reabsorbed by the terminal ileum
95
196
?% of bile salts are lost in feces
5
197
how are reabsorbed bile salts recycled
via enterohepatic circulation
198
enterohepatic circulation
movement of bile acid molecules from the liver to the small intestine and back to the liver
199
sphincter of oddi
- the muscular valve surrounding the exit of the bile duct and pancreatic duct into the duodenum
- sphincter is normally closed, opening only in response to a meal so that digestive juices can enter the duodenum and mix with food for digestion
200
gallbladder
stores and concentrates bile from the liver
201
where does bile go if the gallbladder is removed
common bile duct stores and expands to compensate
202
digestive system malabsorption and deficiencies
- gallstones
- IBD (UC and Crohns)
203
gallstones
- hard, pebble-like pieces of material, usually made of cholesterol or bilirubin, that develop in the gallbladder
- bile in gallbladder can precipitate out to form gallstones
- when gallstones block bile ducts, they can cause sudden pain
204
ulcerative collitis (UC)
- a chronic inflammatory bowel disease (IBD)
- abnormal reactions of the immune system cause inflammation and ulcers on the inner lining of your large intestine
205
inflammatory bowel disease (IBD)
- chronic digestive system inflammation
- ideopathic but suspected that immune system dysfunction is the cause
206
crohns
- a chronic disease that causes inflammation in your digestive tract
- usually affects your small intestine and the beginning of your large intestine
- an inflammatory bowel disease (IBD)
207
IBD treatment
- anti-inflammatories
- suppress abnormal immune system function
208
ileus definition
- a temporary lack of the normal muscle contractions of the intestines
- lack of peristalsis, not caused by a physical block
209
ileus causes
- injury
- inactivity
- infection
- cancer
- medication (morphine)
- volvulus
- surgery
210
volvulus definition
when a loop of intestine twists around itself and the mesentery that supports it, causing bowel obstruction
211
ileus symptoms
- abdominal discomfort
- bloating
- diarrhea
- nausea
- vomiting
- constipation
212
ileus treatment
- electrolytes
- laxatives
- physical activity
213
4 important factors of motility and secretion control
- autonomous smooth muscle function
- intrinsic nerves
- extrinsic nerves
- gastrointestinal hormones
214
how is autonomous smooth muscle function important in motility and secretion
responsible for basic electrical rhythm (BER) that creates peristalsis
215
how are intrinsic nerves important in motility and secretion
- controls local (intrinsic) submucosal and myenteric nerve plexuses
- respond locally to chemical gut changes, mechanical distention
- regulate secretory elements and contractility
216
how are extrinsic nerves important in motility and secretion
control glandular secretion via extrinsic visceral (autonomic) efferents (sight, smell, hearing input) via CNX or vagus
217
how are gastrointestinal hormones important in motility and secretion
controls GI hormones like CCK
218
types of reflexes
- short
- long
219
short reflex triggers
local chemical or mechanical changes
220
long reflex triggers
- external input (5 special senses)
- nerve impulse to digest
221
which pathway does intrinsic nerve plexus use
short reflex
222
which pathway does extrinsic autonomic nerve use
long reflex
223
which pathway do gastrointestinal hormones use
hormonal pathway
224
what kind of pathways are triggered by external influences
long reflex
225
what kind of pathways are triggered by local changes in digestive tract
short reflex, long reflex, hormonal pathway
226
what detects local changes in digestive tract
receptors in digestive tract
227
smooth muscle function
- contraction for motility
- self-excitable
228
exocrine gland function
secrete digestive juices
229
endocrine gland function
secrete gastrointestinal and pancreatic hormones
230
CNS
- brain
- spinal cord
231
PNS
nerve fibers carry info between CNS and body
232
PNS divisions
- afferent
- efferent
233
afferent PNS division
sensory and visceral stimuli input
234
efferent PNS division
- voluntary somatic nervous system (motor neurons and skeletal muscle)
- involuntary autonomic nervous system
235
autonomic nervous system (PNS)
- sympathetic and parasympathetic nervous system trigger smooth/cardiac muscle, exocrine/endocrine glands
- enteric submucosal and myenteric plexus nervous system trigger digestive organs
236
stimuli in digestive tract triggers ?
enteric nervous system (digestive organs)
237
sympathetic nervous system
- inhibit GI tract contraction and secretion
- main function: inhibitory
238
parasympathetic nervous system
- increase GI motility and secretion of digestive enzymes and hormones via vagus nerve
- main function: stimulatory
239
salivary secretion process
- inputs stimulate cerebral cortex
- cerebral cortex and pressure/chemoreceptors stimulate salivary center in medulla
- medulla stimulates autonomic nerves
- nerves stimulate salivary glands which increase secretion
240
types of salivary secretion reflexes
- conditioned
- simple
241
salivary reflexes function
increase salivary secretion
242
oral chemoreceptors
taste buds
243
normal amount of saliva produced per day
1-2 liters
244
simple salivary reflex triggers
- pressure receptors
- chemoreceptors
245
conditioned salivary reflex triggers
- cerebral cortex
- sight, smell, etc.
246
gastric secretion phases
1. cephalic phase
2. gastric phase
3. intestinal phase
247
gastric secretion - cephalic phase (when, why, how it is intensified)
- occurs before food enters the stomach, especially while it is being eaten
- results from sight, smell, thought, or taste of food
- greater the appetite, the more intense is the stimulation
248
end goal of cephalic phase
parietal and chief cells secrete pepsinogen and increase acid
249
excitatory mechanism of cephalic phase
- stimuli: sight, smell, taste, chewing, swallowing
- stimuli excites vagus nerve which stimulates intrinsic nerves and G cells
- intrinsic nerves increase Ach which stimulates chief and parietal cells that secrete gastric secretions
- G cells secrete gastrin which stimulate chief, parietal, and ECL cells which secrete histamine (and further stimulate chief and parietal cells)
250
where does vagus nerve arise
medulla
251
from where does the vagus nerve exit
jugular foramen
252
grp function
release of gastrointestinal hormones to trigger G-cells
253
what is gastrin released into
blood
254
what is histamine released into
lamina propia
255
what is pepsinogen released into
lumen
256
what is Hcl released into
lumen
257
gastric secretion - gastric phase (when, how much of gastric secretion occurs here, and what does it stimulate)
- swallowed food and semi-digested protein (peptides and amino acids) activate gastric activity
- two-thirds of gastric secretion occurs during this phase
- stimulates gastric activity in two ways: by stretching the stomach and by raising the pH of its contents
258
end goal of gastric phase
parietal and chief cells stimulate pepsinogen secretion and increase acid
259
excitatory mechanism of gastric phase
- stimuli: protein (peptide fragments), distension, caffeine, alcohol
- stimuli excites vagus nerve, intrinsic nerves, and G cells
- vagus nerve stimulates intrinsic nerves and G cells
- intrinsic nerves stimulate Ach and G cells increase gastrin secretion
- Ach stimulates chief and parietal cells
- gastrin stimulates chief, parietal, and ECL cells
- chief and parietal cells increase gastric secretion
- ECL cells secrete histamine which stimulates chief and parietal cells
260
gastric secretion - intestinal phase regions
- body and atrum
- antrum and duodenum
- duodenum
261
intestinal phase body and antrum stimuli
removal of protein and distension as the stomach empties
262
intestinal phase antrum and duodenum stimuli
- triggered by an accumulation of acid
- acid secretions mopped up by food and fluid
- when food is gone, acid builds up
263
intestinal phase duodenum stimuli
- fat
- acid
- hypertonicity
- distension
264
inhibitory mechanism of intestinal phase body and antrum
- stimuli: removal of protein and distension as the stomach empties
- stimuli inhibits intrinsic nerves, vagus nerve, and G cells
- G cells decrease gastrin which decreases histamine
- intrinsic nerves, vagus nerve, and decreased histamine inhibit gastric secretion
265
inhibitory mechanism of intestinal phase antrum and duodenum
- stimuli: accumulation of acid
- stimuli excites D cells
- D cells increase somatostatin secretion
- somatostatin inhibits parietal, G, and ECL cells
- these cells being inhibited decreases gastric secretion
266
in gastric secretion, in which phase are the D cells used
intestinal phase
267
inhibitory mechanism of intestinal phase duodenum
- stimuli: fat, acid, hypertonicity, and distension
- stimuli exhibits enterogastric reflex and increases enterogastrones (cholecystokinin and secretin)
- these inhibit parietal, chief, and smooth muscle cells
- these cells inhibit gastric secretion and motility
268
intestinal phase goal
reduce the strength of antral peristalsis
269
enterogastric reflex
- nervous reflex
- duodenum wall stretching decreases gastric motility
- feedback mechanism that regulates how fast we digest food into the small intestine
- enterogastrones hormones released on mucosa
270
stimulation of HCl secretion
- acetylcholine, gastrin, and histamine stimulate HCl secretion by parietal cells
- gastrin-releasing peptide (GRP) increases gastrin release
- gastrin released from G cells increases histamine release from ECL cells
- Ach released by neurons increase histamine release
271
negative feedback control of gastric secretion
- decrease in pH stimulates somatostating secretion by D cells
- somatostatin inhibits secretion by G, ECL, parietal, and chief cells
272
pancreas location
under stomach
273
acinar cells
secretory vesicles released by exocytosis
274
pancreatic secretion occurs ?
at intestinal phase when chyme is in the small intestine
275
control of pancreatic aqueous NaHCO3 secretion
- acid duodenal lumen
- acid stimulates an increase in secretin release from duodenal mucosa
- secretin carried via blood and excites pancreatic duct cells
- increases secretion of aqueous NaHCO3 solution into duodenal lumen
- solution neutralizes acid in duodenal lumen
276
control of pancreatic digestive enzyme secretion
- fat and protein products in duodenal lumen
- increase cholecystokinin (CCK) release from duodenal mucosa
- CCK carried via blood and excites pancreatic acinar cells
- increases secretion of pancreatic digestive enzymes (proteolytic enzymes, pancreatic amylase, pancreatic lipase) from duodenal lumen
- enzymes digest fat and protein products in duodenal lumen
277
secretin purpose
neutralize acid
278
cholecystokinin purpose
digests acid
279
bile salts purpose
- absorb fat produced in liver
- pancreatic duct into duodenum
280
gallbladder fundus
281
gallbladder body
282
gallbladder neck
