Gastrointestinal Physiology Flashcards
(286 cards)
1
Q
what are the four processes of digestion?
A
- secretion
- digestion
- motility
- absorption
2
Q
what is secretion?
A
- enzymes being secreted in tubes of digestive tracts
- saliva in mouth and acid in stomach
- enzymes used to break down food
3
Q
what is amalase?
A
enzyme that breaks down carbs
4
Q
what are the two types of digestion?
A
mechanical (big to small through chewing) and chemical (uses enzymes, needed to absorbed nutrients)
5
Q
what is motility?
A
moving food from mouth to rectum (movement at a carefully controlled speed; peristalsis)
6
Q
what is absorption?
A
how to get nutrients into bloodstream (once small enough, moves through epithelial cells and becomes absorbed for nutrients)
7
Q
what are three accessory organs of the digestive system?
A
gallbladder, liver and pancreas
8
Q
what is the job of the oral cavity?
A
secretion
9
Q
what does secretion do?
A
- lubricates
- helps with ability to taste our food
- protects mouth and teeth
- aids with speech
10
Q
describe saliva composition
A
- mostly water and ions such as sodium and chlorine
11
Q
what are the three salivary glands?
A
- parotid gland
- submandibular gland
- sublingual gland
12
Q
where is the parotid gland found?
A
cheeks area
13
Q
where is the submandibular gland found?
A
under mandible
14
Q
where is the sublingual gland found?
A
under tongue
15
Q
describe the three types of salivary glands
A
parotid gland = watery
submandibular gland = music and watery saliva
sublingual gland = mostly mucus
16
Q
what is the term used to describe mechanical digestion through chewing?
A
mastication
17
Q
chemical digestion in the oral cavity is done by what salivary enzyme?
A
amylase
18
Q
is lingual lipase active when in the oral cavity?
A
NO, lingual lipase is activated in the stomach
19
Q
(oral cavity) three steps of motility :
A
- mastication (chewing); mechanical motility, movement from back to front of mouth
- swallowing (only cavity to the esophagus)
- peristalsis : top to bottom of esophagus
20
Q
“co-ordinate contraction of the muscles in the esophagus, involuntary control, propels bolus towards the stomach” is all used to describe…
A
peristalsis
21
Q
what are the two “movements” of peristalsis and what does it do”?
A
- longitudinal (push it down)
- circular (constrict)
22
Q
what is absorbed in the oral cavity (bare minimal absorption) and where does it mostly occur?
A
glucose / drugs and mostly occurs under the tongue
23
Q
what organ acts as a reservoir for bolus before it enters the intestine?
A
stomach
24
Q
what liquid/acid is found in the stomach?
A
hydrochloric acid
25
how does bile become chyme?
it mixes with the acid in stomach
26
what part of body leads into the stomach?
esophagus (through diaphragm)
27
where does the esophagus attach?
to the cardia
28
what does the lower esophageal sphincter do?
stops stomach acid from coming up?
29
which side of the stomach has a bigger curve?
left side (greater curvature)
30
what happens if too much acid is getting pushed up?
- acid reflex (sphincter isn't closed all the way)
- increase abdominal pressure
31
what part of the stomach attaches to the small intestine?
antrum
32
what is the sphincter at the end of the stomach?
pyloric sphincter
33
when does the pyloric sphincter open?
only opens when food needs to go into the intestine
34
what are the four layers of the stomach?
- muscosa
- submucosa
- smooth muscle (muscular externa)
- serosa
35
describe the mucosa?
- innermost
- protect stomach from bacteria and acid
36
describe the submucosa? (stomach)
- neural network (info being sent)
- has submucosal plexus (helps with mucous excretion)
37
describe the smooth muscle?
- muscular contractions of the stomach
- circular and longitudinal muscle to change shape of stomach
contains a neural network (myenteric plexus; peristalsis)
38
describe the serosa?
- protective layer
- dense connective tissue
- outermost
39
which layer of the stomach is responsible for muscular contractions of the stomach?
smooth muscle (muscular externa)
40
what layer protects the stomach from bacteria and acid?
mucosa
41
which layer has a submucosal plexus that is responsible for helping with mucous excretion, etc.
submucosa
42
what are the three exocrine cells of the stomach?
1. mucous neck cells
2. chief cells
3. parietal cells (oxyntic cells)
43
what is the endocrine cell of the stoamch?
G cells
44
what does mucus neck cells do?
secrets mucous and bicarbonate (to protect stomach)
45
what do chief cells do?
secretes pepsinogen and gastric lipase
46
what is pepsinogen?
the inactive version of pepsin
47
what is the endocrine cell of the stomach?
G cells
48
what do G cells do?
secrete the hormone gastrin
49
what does gastrin do?
releases HCl and stimulates gastric acid
50
what do parietal cells do?
secretes H+ and Cl - (HCl) and intrinsic factor
51
what is intrinsic factor?
helps absorb B12 and terminal ileum
52
what are the three movements of digestion in the stomach?
propulsion, grinding and retropulsion
53
describe the direction of propulsion, grinding and retropulsion ...
- propulsion = moving foward
- grinding = circular contraction
- retropulsion = pushing backwards as we let little amounts move through
54
how does bolus become chyme through chemical digestion?
- secreted gastric juices contain HCl
- secreted pepsnogen converted to pepsin
55
what does pepsin do?
pepsin is the active for of pepsinogen and it is an enzyme that aids in protein digestion in the stomach
56
name the 6 functions of acid in the stomach
1. activation of lingual lipase (lipid digestion can occur)
2. activation of pepsin (from pepsinogen)
3. inactivation of salivary amylases
4. kills microbes (with HCl)
5. denatures proteins
6. stimulates secretion of hormones
57
where does carbohydrate digestion completely stop?
in the stomach
58
what are the three parts of the small intestine?
1. duodenum
2. jejunum
3. ileum
59
where does nutrient absorption occur?
small intestine
60
what is the job of the duodenum?
decreasing acidity of chyme
61
what is the job of the jejunum?
absorption (increase SA)
62
what is the job of the ileum?
responsible for absorption and digestion of nutrients and vitamins like B12, etc and everything else not absorbed prior
63
where does most absorption in the small intestine occur?
jejunum
64
what does villi in the jejunum do?
increases surface area for optimal absorption
65
what are the four layers of the small intestine?
1. mucose
2. submucosa
3. smooth muscle (musularis)
4. serosa
66
what's the difference between layers of the stomach and the small intestine?
- the mucosa of small intestine is responsible for mucus secretion
- the mucosa of the stomach is responsible for protects the stomach from bacteria and acid
- serosa is opposite of each other (small intestine very thing and stomach thick)
67
what does the myenteric plexus do?
controls the muscles (peristalsis)
68
what are the two movements of motility of the small intestine?
segmentation and peristalsis
69
what it segmentation?
mixing back and fourth, allowing for touching (increases the interactions of particles of food in chyme with absorptive cells of the mucosa layer)
70
name the 7 cell types of the small intestine?
1. absorptive cells
2. goblet cells
3. K cells
4. intestinal gland cells
5. paneth cells
6. S cells
7. CCK cells
71
what do absorptive cells do?
helps absorption of nutrients (epithelial cells with microvilli)
72
what do goblet cells do?
secretes mucus
73
what do intestinal gland cells do?
secretes alkaline watery mucus and helps protect from acid of stomach
74
what do paneth cells do?
secretes lysozyme (helps fight against pathogens)
75
what do S cells do?
secretes secretin
76
what do CCK cells do?
secretes cholecystokinin
77
what do K cells do?
secretes (GIP)
78
what does secretin tell the liver/pancrease to do and is it a hormone/enzyme?
- hormone not an enzyme
- tells liver and pancreas to separate its enzymes
79
what does GIP do ?
stimulates insulin to be secreted
80
what does cholecystokinin (CCK) do ?
tell pancreas to secrete enzymes and gall bladder to contract
81
where is bile created and stored?
created in the liver and stored in gallbladder
82
what does microvilli do?
increases surface area for absorption of nutrients
83
what is the very last step in regards to chemical digestion?
microvilli
84
what are brush border enzymes
cells on the microvilli (which have enzymes)
85
what are the 6 brush border enzymes?
1. lactase
2. sucrase
3. malatase
4. aminopeptidase
5. dipeptidase
6. enteropeptidase
86
what is lactose broken down by?
lactose is broken down by lactase into glucose + galactose
87
what is sucrose broken down by?
sucrose is broken down by sucrase into glucose and fructose
88
what is maltose broke down by?
maltose us broken down by maltase into glucose and glucose
89
where are brush border enzymes mostly found?
in duodenum
90
what does aminopeptidase do?
removes one amino acid from the end of a protein
91
what does dipeptidase do?
cuts a dipeptide into two single amino acids
92
what does enteropeptidase do?
cuts trypsinogen into trypsin
93
what does the large intestine do?
- completes absorption (usually water)
- highly populated by bacteria
- beneficial for completing nutrient extraction
- reabsorbes water
94
what are three points of motility of the large intestine
- gastroileal reflex
- haustraul churning
- peristalsis and mass peristalsis
95
what does the gastroileal reflex do?
presence of food in the stomach stimulates the opening of the ileocecal valve (neural reflex)
96
what does haustral churning do?
responsible for mixing of elements and allows for optimal absorption of mostly water from lumen contents
97
what does peristalsis and mass peristalsis do?
unidirectional movement of lumen contents out of the large intestine (into rectum) (feeling of having to go to the washroom)
98
what organ has both endocrine and digestion function?
pancreas
99
what are the names of epithelial cell clusters and the cells that form the ducts that together make exocrine secretions ?
acinar and ductal cells
100
where does the pancreas secrete directly into?
the duodenum
101
what comes from ductal cells?
bicarbonate
102
what does bicarbonate do?
neutralizes the acid from the stomach
103
what 7 enzymes come from acinar cells ?
1. pancreatic amylase
2. pancreatic lipase
3. trypsinogen = trypsin
4. chymtrypsinogen = chymotrypsin
5. procarboxypeptidase = carboxypeptidase
5. prophospholipase = phospohlipase
6. procolipase = colipase
104
what type of carbohydrate is amalose?
complex carbohydrate
105
what is pancreatic amylase?
enzyme from pancreas breaking down
106
what is pancreatic lipase?
enzyme that breaks down lipids
107
what is trypsinogen?
inactive form that is further turned into trypsin (active form) used for the breakdown of proteins
108
what is chymotrypsinogen?
trypsin converts chymotrypsinogen into chymotrypsin which is used in the breaking down of proteins found in chyme
109
what converts procarboxypeptidase into carboxypeptidase?
trypsin converts procarboxypeptidase into carboxypeptidase
110
what is prophospholipase?
prophospholipase is the active form from procarboxypeptidase
111
what happens to the amino group during carboxypeptidase?
take off amino group @ end of carboxy
112
what does colipase do?
works as cofactor with pancreatic lipase
113
what is used to turn chymotrypsinogen, procarboxypeptidase and prophospholipse into its active form?
trypsin
114
what does trypsin do?
activates enzymes that cuts proteins
115
where do acinar cells come from?
pancreatic duct
116
what are the three islets of langehans?
1. insulin
2. glucagon
3. somatostatin
117
what type of cells does insulin come from?
beta cells
118
what type of cells does glucagon come from?
alpha cells
119
what type of cells does glucagon come from?
delta cells
120
what does insulin do?
monitors glucose levels in the blood (hyper; too much)
121
what does glucagon do?
too little glucose in bloodstream; converts into glucose (hypo; too little)
122
what does the liver do ?
- clean blood
- duo portal system
- take all bad things and excrete them
** liver can regenerate
123
what are the arteries that go to the stomach ?
digestive tract arteries
124
what is the "bed"called that has oxygen, nutrients, glucose, etc?
sinusoids (capillary bed)
125
anything leaving the liver exists through the...
hepatic vein
126
blood going towards liver that delivers lots of oxygen ...
hepatic vein
127
sinusoids join together to form what?
the central vein, and then the hepatic vein
128
where does bile get secreted by?
hypothalmus
129
what do hepatocytes do?
secrete bile into a vessel called a bile canaliculus
130
small vessels in the liver gather together and join to form the ...
bile duct
131
bile ducts come together to form ...
hepatic ducts
132
what are hepatocytes?
main liver cell that decides what goes where (makes decisions)
133
four functions of the liver...
1. synthesis of bile
2. excretion of bilirubin
3. metabolism of carbohydrates, lipids and proteins
4. processing drugs and hormones
134
what are the components of bile salts?
- bile salts
- cholesterol
- bile pigments (bilirubin)
- water and ions
135
what does bile do?
help with lipid digestion
136
what is bilirubin?
waste product that gives the colour of urine
137
bilirubin leads to the breakdown of ...
haemoglobin (red blood cells)
138
what are the two types of cholesterol ?
GOOD = HDL (high)
BAD = LDL (low)
139
what is the sphincter at the end of the gallbladder called
sphincter of oddi
140
is the sphincter of oddi usually open or closed?
closed all the time until needed to open at the right time to let things through
141
what does the gallbladder do?
stores bile
142
what happens when you eat a high fat meal?
contraction of gallbladder, pushes bile out and help with lipid digestion (CCK)
143
what does the common bile duct do ?
carries bile from liver to the pancreas and then into the small intestine
144
where does bile solution become concentrated?
gallbladder
145
what is the cystic duct?
tube that carries bile from the gallbladder
146
what two ducts come together to form the common bile duct?
cystic and hepatic duct
147
bile solution enters into the duodenum through the opening of ...
the sphincter of oddi
148
what does CCK do to the gallbladder?
causes the gallbladder to squeeze and the sphincter of oddi opening to be released into the duodenum
149
what are the three phases of coordination of the gastrointestinal tract?
- cephalic phase (brain)
- gastric phase (stomach)
- intestinal (small intestine)
150
what happens when there is a slower rate (motility) in the large intestine?
diarrhea
151
what is the stimulus of the cephalic phase
sight, smell and taste of food (anticipation of food through neural control)
152
neural control of the cephalic phase is through the ...
medulla oblongata
153
where is the medulla oblongata found ?
in the brainstem
154
(cephalic stage) increased secretions come from:
- salivary glands (saliva)
- stomach (HCI)
- small intestine (mucus)
155
what is the stimulus of the gastric phase?
presence of bolus (food) in the stomach causing stretching, presence of amino acids
156
neural control of the gastric phase is through ...
sensory information to the submucosal plexus and the myenteric plexus
157
what is the term that "helps with the emptying of the stomach into the small intestine" ?
motility
158
hormonal control of the gastric phase is ...
gastrin (G cells)
159
what type of cells are gastrin?
G cells
160
gastric phase causes increased secretions from :
- stomach (HCl)
- intestine (mucus)
161
what is the stimulus of the intestinal phase?
presence of chyme in the intestine
162
neural control of small intestine is through ...
sensory information to the submucosal plexus (secretions) and myenteric plexus (motility)
163
hormonal control of the intestinal phase is ...
secretin (S cells), CCK (CCK cells), GIP (K cells)
164
what does GIP do?
tells pancreas to release insulin (needed in blood)
165
increased motility of intestinal phase is through ...
- intestine (segmentation and peristalsis)
- gallbladder contraction
166
what phase inhibits another phase?
the intestinal phase inhibits the gastric phase
167
what are the two types of carbohydrate sources?
simple and complex
168
simple carbohydrates are either called __ or __ :
monosaccarides or disaccharides
169
what are the three monosaccharides ?
glucose, galactose and fructose
170
what are the three disaccarides ?
lactose, sucrose and maltose
171
complex carbohydrates are either called __ or __ ?
starch or glycogen
172
where does starch come from ?
plant storage of glucose
173
where does glycogen come from?
animal storage of glucose
174
where does carbohydrate digestion occur?
mouth
175
where is carbohydrate digestion completely inhibited?
stomach
176
what enzyme is inactive in the stomach due to acid in the stomach (carbohydrate digestion)
salivary amylase
177
where does carb digestion further continue after the stomach?
the pancreas (pancreatic amylase present)
178
where does chemical digestion of carbs occur?
mouth and small intestine
179
what does finer do?
help with digestion, motility and function
180
salivary amylase turns starch into what?
maltose
181
how does fructose move through cell?
fructose moves alone (symporter)
182
what cotransporter does glucose and galactose need?
sodium
183
describe the concentration gradient of sodium...
sodium is always higher on the outside and lower in the inside
184
when sodium exists the cell what enters it?
potassium
185
what is a uniporter?
transport protein that moves a single species of substrate across a membrane
186
what is needed for the exchange of Na and K ?
ATP
187
which organ in body will help with the digestion of fructose?
large intestine
188
what happens if theres too much fructose in the large intestine?
constapation / GI upset
189
what are allergies vs intolerance
- allergies = immune system will attack the good & make sick
- intolerance = not feeling great, upset & uncomfortable
190
how many amino acids are there
20
191
how many essential and nonessential amino acids are there?
9 essential & 11 nonessential
192
what is an essential amino acid?
one the body cannot create / must be consumed
193
what is a nonessential amino acid?
one the body can create naturally
194
what is a di, tri and poly - peptide?
di = 2 amino acids bonded together
tri = 3 amino acids bonded together
poly = many amino acids bonded together
195
where does protein digestion occur?
stomach
196
what enzyme is used in the stomach for protein digestion?
pepsin (active form that comes from pepsinogen)
197
aminopeptidase is in what organ?
small intestine
198
what breaks pepsin, trypsin and chymotrypsin into smaller fragments?
endopeptidase
199
what is a further break on the aminopeptidase side called?
amino terminus
200
what is a break on the carboxypeptidase side called?
carboxy terminus
201
how do we classify protein digesting enzymes that cut somewhere in the middle?
endopeptidase
202
how do di and tri-peptides enter the cell?
bring themselves in
203
how do amino acids enter the cell?
needs a co transporter (Na)
204
once di and tri-peptides enter the cell what breaks them down into amino acids?
peptidase
205
what is a tryglyceride?
type of fat
206
what is the composition of a triglyceride ?
glycerol and 3 fatty acids
207
what is the variable length in fatty acids ?
4 - 24 carbons
208
what is considered the most common number of carbons in a fatty acid?
18 carbons
209
what are saturated fats?
- more unhealthy
- no double bond present
- more solid
210
what are unsaturated fats?
- healthier
- double bond present
- more fluid (liquid)
211
in order to break more double bonds in unsaturated fats what must be present?
more energy (lose more calories)
212
what are trans fats?
found in processed food, more LDL (worst type of fat)
213
where does lipid digestion occur?
small intestine
214
what enzyme is in the mouth responsible for little bit of lipid digestion?
lingual lipase
215
where do tryglerides gets digested ?
stomach and small intestine
216
what are bile salts?
component of bile
217
where are bile salts found?
lipids (fats)
218
what is jaundice disease?
condition that involves having too much bilirubin
219
who tends to have jaundice disease?
alcoholics/drug users/babies
220
what pushes bile salts apart so that the lipase can touch the surface of the small lipid droplet ?
colipase
221
what form lipid droplets?
triglycerides
222
what part of tryclerides face the outside of lipid digestion?
hydrophobic heads
223
what is wrapped around liquid droplets?
bile salts
224
what is a diglyceride?
one fatty acid is off
225
what is a monoglyceride?
two fatty acids off
226
what is a free fatty acid?
no head present just tails
227
what is a michelle?
small fat droplet covered with bile
228
where do Michelles happen?
small intestine
229
in what situation can bile be in the stomach ?
vommiting
230
what "helps package lipids in order to move around the body"?
chylomicrons
231
what are chylomicrons ?
help pack lipids in order to move around the body
232
where does the best fat digestion occur?
small intestine
233
what are two classifications of vitamins ?
fat soluble and water soluble vitamins
234
what are examples of fat-soluble vitamins?
- vitamin A
- vitamin D
- vitamin E
- vitamin K
235
what are examples of water-soluble vitamins?
- vitamin C
- vitamin B
- B12
236
what does vitamin C do?
help with immune function
237
what occurs in the cytoplasm during digestion ?
glycolysis and pyretic acid
238
what is glycolysis?
breakdown of glycologen
239
what does pyretic acid turn into?
lactic acid
240
what does lactic acid do?
breakdown of muscles and glucose
241
what occurs in the mitochondria during digestion?
pyretic acid, acetyl CoA, CoA, citric acid cycle ... electron transport system
242
what does the citric acid cycle do?
trying to produce ATP (for aerobic respiration)
243
what is the primary source of energy ?
carbohydrates
244
what happen to carbs in our body?
- ATP production
- amino acid synthesis
- glycogen synthesis
- triglyceride synthesis
245
what is glycolysis ?
breakdown of glucose by enzymes, releasing energy and pyruvic acid
246
what is amino acid synthesis ?
converted to some amino acids if needed (protein creation)
247
what is glycogenesis ?
formation of glycogen without the use of glucose (storage of glucose)
248
what is lipogenesis ?
formation of fat
249
what does triglyceride synthesis mean in regards to glucose ?
too much glucose
250
what does glucose uptake mean?
cells of the body take glucose from the blood in order to use for the production of ATP
251
through what concentration gradient does glucose move?
region of high concentration (blood) to a region of low concentration (cell)
252
in what state does carbohydrate fates glycogenesis occur?
fed state
253
what 2 cell types have a large capacity to store glucose as glycogen?
skeletal muscle and liver
254
where does glycogenesis happen?
liver
255
how does glucose become glycogen?
glucose -> 6- phosphate (G6P) -> glycogen
256
what is added to glucose to form bonds to create glycogen?
phosphate
257
in what state of carbohydrate fates glycogenolysis occur?
fasted state
258
how does glycogen become glucose?
glycogen -> G6P -> liver -> glucose
259
how does the liver create new glucose molecules?
through non carb sources (amino acids, lactic acid and glycerol)
260
in what state does gluconeogenesis occur?
fasted state
261
what is "any fat you see on you body" ?
adipose tissue
262
_____ is the fat right under skin; used on energy storage for starvation
adipose tissue
263
what are the 4 fates (what happens in our body) of lipids ?
- stored in adipose tissue as fat deposits
- oxidizes to produce ATP
- formation of structural molecules
- triglyceride storage
264
what do myelin sheaths do?
speed up transduction
265
where is majority of our energy needed daily stored ?
trigylerides
266
what is lipolysis ?
breakdown of triglycerides into glycerol and fatty acids
267
in what state does lipolysis occur?
fed state
268
"most simple form of alpha keto acid"
pyruvic acid
269
what happens if theres too much fat in the body?
leads to weight gain
270
in what state does lipogenesis occur?
fed state
271
what is an alternate energy source in the body?
ketones
272
what is ketogenesis?
creation of ketone bodies by breaking down fatty acids and ketogenic amino acids
273
how are ketone bodies formed?
by joining two acetyl coenzyme A molecules together
274
what are liver cells called?
hepatocytes
275
can liver cells make ketone bodies ?
yes ! which later diffuse into the blood
276
in what state does ketogenesis occur?
fasted state
277
what cell types prefer ketone bodies to produce ATP?
heart and kidney cortex
278
"depleting yourself of glucose"
ketones
279
how do organisms produce ketone bodies ?
organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids
280
what is protein anabolism ?
formation of proteins from amino acids
281
what is protein catabolism?
breakdown of proteins into amino acids
282
in what state does protein anabolism occur?
fed state
283
in what state does protein catabolism occur?
fasted state
284
what components of our bodies are made up of proteins?
enzymes, hormones, structural components, transporters
285
amino acids from proteins can be converted into ...
fatty acids, glucose and ketone bodies
286
what organ coverts amino acids into fatty acids, ketone bodies and glucose?
liver
