Download 16 GI Physio flashcards

Digestive (GI) Physiology
1. What are the three main simple sugars?
Glucose, fructose, and galactose
2. What is maltose made of?
Glucose + glucose
3. What is lactose made of?
Glucose + galactose
4. What is sucrose made of?
Glucose + fructose
5. What is a polysaccharide (complex
carbohydrate) made of?
The joining of many monosaccharides and
disaccharides.
6. Where are complex carbohydrates
stored, and in what form?
They are stored as glycogen in the liver
7. What do complex carbohydrates break
down into?
Glucose
8. What is the storage form of
carbohydrates in plants called?
Starch
9. Can we use starch?
Not directly. We convert it to glucose, which
is the form we can use.
10. What Organ secretes Glucagon?
Pancreas
11. What organ secretes insulin
Pancreas
12. What does Glucagon do to blood
glucose levels?
Raises blood glucose
13. What does insulin do to blood glucose
levels?
Lowers blood glucose levels
14. When does the pancreas release
glucagon?
When blood sugar levels fall too low,
especially between meals
15. When does the pancreas release
insulin?
When blood sugar levels are too high,
especially after meals
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16. What is glycogenolysis?
The breakdown of glycogen into glucose
17. What is glycolysis?
The breakdown of glucose to pyruvic acid,
and ATP is formed.
18. What is the difference between
glycogenolysis and glycolysis?
Glycogenolysis is the breakdown of glycogen
into glucose.
Glycolysis is the breakdown of glucose into
ATP
19. When is Insulin released?
When there are high blood glucose levels
20. What does insulin do to decrease
blood glucose levels?
Insulin takes the glucose into cells that need
it for glycolysis to produce ATP
21. How do glucagon and insulin work
together?
To keep blood glucose levels at a stable
level.
22. What other two simple sugars can be
broken down into pyruvate and ATP?
Fructose and galactose
23. During glycolysis, what energy
molecule is used up, which needs to be
replaced, and how do we do that?
NAD is used up because it is reduced to
NADH. We need to oxidize it back into NAD
by anaerobic or aerobic respiration.
24. How many molecules of ATP are used
during glycosis?
2 ATP molecules
25. How many ATP are made during
glucolysis?
4 are made
26. What is the net gain of ATP in glycosis?
2 ATP molecules
27. What does a cell do immediately after
finishing glycolysis?
Aerobic or anaerobic respiration, depending
on the availability of oxygen.
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28. In what part of a cell is aerobic
respiration performed?
In the mitochondria
29. In what part of a cell is anaerobic
respiration performed?
In the cytoplasm
30. How many ATP result from Aerobic
Respiration?
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31. How many ATP result from anaerobic
respiration?
2
32. What molecule is regenerated during
respiration, and what is it used for?
NADH is oxidized to NAD, so glycolysis can
continue.
33. Where is Aerobic Respiration
performed?
Mitochondria
34. Positives of making ATP this way:
35. Negatives of making ATP this way:
 Can make a lot of ATP
 Takes a long time to Make ATP because
we need oxygen to make it.
36. What are the waste products of
aerobic respiration?
 Waste products are CO2 and H2O (we
exhale them)
37. Where is Anaerobic Respiration
performed?
Cytoplasm
38. Positives of making ATP this way:
39. Negatives of making ATP this way:
40. What is the waste product of
anaerobic respiration?
41. Under what conditions will pyruvate
use anaerobic respiration?
 We can make it FAST.
 That it does not make much ATP, and we
deplete the reserves quickly.
 Waste product is lactic acid
In muscle during strenuous workouts when
oxygen becomes deficient.
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42. What enzyme takes the hydrogen from
NADH during anaerobic respiration?
Lactate dehydrogenase
43. Where does the hydrogen ion go after
it is removed from NADH?
It is placed on pyruvate, which turns it into
lactate.
44. How is lactic acid formed?
From lactate
45. What does lactic acid build-up in
muscles do to the body?
Causes muscle aches and fatigue
46. How do you deactivate lactic acid?
48. Can we store ATP?
Add oxygen to it. It goes back to being
pyruvate plus water.
Soak them in warm water or use ultrasound
to increase circulation. Oxygen will be able
to turn the lactic acid into pyruvate and
water.
 No
49. What can muscles do to store energy
for future periods of activity?
Muscles convert excess ATP to creatinine
phosphate, which can be stored.
50. When is creatinine phosphate broken
down to produce ATP?
When the small reserves of ATP existing in a
cell are used first.
51. When do we use aerobic respiration?
Resting and running a marathon (whenever
we can breathe easily enough to talk).
52. How a marathon runner would make
sure he or she would enough readily
available energy for the muscles?
By eating a lot of carbohydrates over a twoday period before the marathon
(carbohydrate loading).
53. When do we use anaerobic
respiration?
Sprint running (whenever we cannot
breathe easily enough to talk).
54. What is gluconeogenesis?
generation of new glucose from lactate,
glycerol or amino acids
47. What can you do to make muscle
aches go away?
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55. If we do not have enough glucose
in our body, what do we break down to
make glucose?
-Proteins (muscles)
56. What are the two main mechanisms to
keep blood glucose levels from dropping
too low?
-Gluconeogenesis
57. What is the function of saliva?
To clean the oral cavity and moisten the
food.
58. What enzyme does saliva have?
Amylase
59. What two things does amylase break
down?
polysaccharides and disaccharides
60. Give an example of a polysaccharide
Starch
61. What is the function of mucous in the
saliva?
Helps soften the food and form it into a
bolus
62. What coordinates the mechanism for
swallowing?
medulla oblongata and pons
63. What initiates the swallowing reflex?
touch receptors in the pharynx are
stimulated when the bolus of food is pushed
to the back of the mouth
64. Where does protein digestion begin?
In the stomach
65. Where are mucous cells located?
In the stomach
66. What do they secrete?
Mucous
67. What is the function of this secretion?
Protect the stomach lining from being
digested
68. What two things do the parietal cells
of the stomach secrete?
Hydrochloric acid (HCl) and intrinsic factor
- Breakdown of glycogen (glycogenolysis)
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69. What is the function of intrinsic factor?
Enables the absorption of vitamin B-12
70. What is vitamin B12 used for?
To make RBC’s (red blood cells)
71. What are the three functions of HCl?
1) Cuts pepsinogen into pepsin, which
digests proteins
2) Kills many microorganisms that are
ingested with the food.
3) Denatures proteins.
It does not break down food.
72. Does it break down food?
73. What do the chief cells secrete?
Pepsinogen
74. What does pepsin do?
Breaks down proteins to the individual
amino acids
75. What do G cells secrete?
Gastrin
76. What three things protect the stomach
lining?
Mucous, bicarbonate, prostaglandins
77. What is the term used to describe low
gastric acidity?
Hypochlorhydria
78. Name 5 diseases associated with
Hypochlorhydria
Asthma, coeliac disease, eczema,
osteoporosis, and pernicious anaemia
79. What is the term used to describe high
gastric acidity?
Hypochlorhydria
80. Name 3 conditions associated with
hypochlorhydria
Heartburn, gas, ulcers
81. What are the symptoms of
hypochlorhydria?
Causes malabsorption and related
symptoms (gas, diarrhea, anemia)
82. Why does anemia result from
malabsorption problems?
Folic acid, vitamin B12 and iron will not be
absorbed if there is too little acid
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83. What is the function of the
Duodenum?
84. What are four hormones that the
Duodenum secretes and what are their
functions?
 Absorption of minerals
 Receives pancreatic digestive enzymes
 Secretes hormones
 Secretes enzymes
Secretin
Tells pancreas to secrete bicarbonate
Tells liver to make bile
Cholecystokinin (CCK)
Tells pancreas to release protein-digesting
enzymes
Tells the gallbladder to release stored bile
Therefore, it stimulates digestion of fat and
protein
GIP
stimulates insulin secretion
85. What are the three enzymes secreted
by the duodenum, and their functions?
Motilin
Initiates peristalsis (increases GI motility)
Tells the Chief cells to secrete pepsinogen
Maltase (breaks down maltose into glucose)
Lactase (breaks down lactose into galactose
and glucose
86. What is produced when amylase
breaks down starch?
87. What breaks down maltose?
88. What does it break down into?
89. Where is maltose found in nature?
Sucrase (breaks sucrose down into fructose
and glucose)
Maltose
Maltase
Two glucose molecules
-Barley, caramelized glucose, malted milk
shakes, malt liquor and beer
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90. What sugar is needed for milk
production?
91. How is lactose made?
Lactose
92. What enzyme breaks down lactose?
Lactase
93. What ethnic groups often lack lactase?
Asians and Hispanic
94. What symptoms are produced in a
lactose intolerant person who consumes
dairy products?
95. What is an example of sucrose?
96. What is an example of Fructose?
97. Polysaccharide sugars and starches are
broken down into what?
Diarrhea and gas
98. Where are K cells found?
In the duodenum and jejunum
99. What do K cells secrete?
Glucose-dependent insulinotropic peptide
(GIP)
100. What does GIP do?
Stimulates insulin and lipase secretion from
the pancreas
101. When do K cells secrete GIP?
When there is no more chime entering the
duodenum
102. What does insulin do with glucose in
the blood?
103. What does lipase do?
It pulls them into cells that need it.
104. What does bile do? Is it an enzyme?
It emulsifies fat (breaks large drops into
small droplets). It is a soap, not an enzyme.
105. What type of complex is formed from
bile salts?
Micelles
Glucose + galactose
Table sugar
Fruit
Glucose
Breaks fat down into fatty acids and
monoglycerides
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106. What are micelles?
small spherical globules of fat surrounded by
bile salts
107. How do fatty acids and
monoglycerides enter intestinal cells?
108. What is used to transport the
monoglycerides into the intestinal cells?
What happens after this substance drops
off the monoglycerides?
109. What happens to the monoglycerides
when it enters the intestinal cell?
By diffusion.
110. After chylomicrons are produced,
where are they transported to?
They are transported to a lacteal (lymph
capillary) within the villus of the small
intestine.
111. Once in the lacteal, where is the
chylomicron’s next location?
They will travel in the lymph until they reach
the thoracic lymph duct, which dumps into
the subclavian artery
112. What is absorbed in the jejunum?
Water-soluble vitamins, protein and
carbohydrates.
113. Where in the body do proteins begin
to break down?
Proteins began to be break down into amino
acids in the stomach by pepsin and acid.
114. In what part of the digestive tract are
proteins broken down into amino acids?
What enzymes do this?
115. Where is trypsin and chymotrypsin
made and secreted from?
They are broken down in the duodenum.
Protein enzymes are trypsin and
chymotrypsin
Made by the pancreas and secreted into the
duodenum.
116. Carbohydrates, nucleic acids, and
proteins are broken down by enzymes that
are made where?
They are broken down in the duodenum by
enzymes mainly from the pancreas and
small intestine.
Bile salts. They are reused.
It is combined with proteins to form a
chylomicron
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117. Lipids are broken down by enzymes
that are made where?
118. What 4 things does the ileum absorb?
The liver
119. In what part of the digestive tract are
fats broken down? What are they broken
down into?
120. How are fats broken down?
Fats are broken down into fatty acids in the
duodenum
121. Which 2 hormones regulate the
secretion of pancreatic juice?
122. Where are secretin and
cholecystokinin produced?
123. What stimulates the secretion of
secretin and cholecystokinin?
secretin and cholecystokinin
124. What enzymes does the pancreas
produce to break down fats, starches, and
proteins?
Lipases (fats)
125. What are the functions of Lipases?
Fat-soluble vitamins, fat, cholesterol and bile
salts
First, bile emulsifies the fat (breaks it down
into droplets)
Then lipase breaks the fat into fatty acids
produced by walls of the duodenum
The presence of acidic food, proteins and
fats in the duodenum
Amylases (starches)
Proteases (proteins)
Digestion of fats, oils, and fat-soluble
vitamins.
126. What are the functions of Amylases?
Breaks down starch molecules into smaller
sugars and breaks down carbohydrates into
maltose, and then into glucose.
127. What are the 2 functions of Proteases?
Breaks down protein into amino acids and
keeps the small intestine free from parasites
(worms, yeast, bacteria).
128. Name three Protease enzymes
Trypsin, Chromotrypsin, and
Carboxypeptidase.
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129. What happens when someone lacks
Proteases?
Incomplete digestion that can lead to
allergies and the formation of toxins.
130. When are Secretin and Cholecystokinin
(CCK) secreted from the duodenum into the
bloodstream?
When fatty or acidic chyme enters the
duodenum.
131. Once Secretin and CCK enter the
bloodstream, where do they go?
To the pancreas.
132. Upon reaching the pancreas, what
does…
a. Secretin do?
a. causes secretion of bicarbonate to
neutralize stomach acids.
b. CCK do?
b. induces the secretion of digestive
enzymes that can digest lipids, proteins, and
carbohydrates.
133. Which nerve also stimulates the
secretion of pancreatic juices?
Vagus nerve (CN X).
134. 98% of the function of the pancreas is
what?
Exocrine function; secretes digestive
enzymes
135. What cells in the pancreas secrete the
digestive enzymes?
Acinar cells
136. 2% of the function of the pancreas is
what?
Endocrine function; secretes insulin,
glucagon, digestive enzymes, somatostatin
137. What cells in the pancreas secrete
somatostatin?
-cells (delta cells)
138. What cells in the pancreas secrete
insulin?
β-cells (beta cells)
139. What cells in the pancreas secrete
glucagon?
α-cells (alpha cells)
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140. What is the main function of insulin?
Lowers blood sugar
141. What is the function of glucagon?
Raises blood sugar
142. What is the function of gastrin?
Increases HCl secretion in the stomach
143. What is the function of somatostatin?
inhibitory to gastrin, insulin, and glucagon
(inhibits the digestive system)
144. What three processes are inhibited by
insulin?
Fat breakdown (lipolysis)
Glycogen breakdown (glycogenolysis)
Formation of new glucose (gluconeogenesis)
145. How are proteins and fats influenced
by insulin?
Insulin promotes fat storage and protein
synthesis
146. What effect does epinephrine have on
insulin, and why?
It inhibits insulin so blood sugars can remain
high during stress, and fat can be broken
down to make more glucose if needed.
- Water and electrolytes
147. What are the two main things that are
absorbed by the large intestine?
148. What allows for fermentation/break
down of substances that remain after
processing in the small intestine?
- Gut bacteria
149. What is the main substance broken
down by intestinal bacteria? Why is this
important?
- Complex polysaccharides. This is
important because we can only digest three
disaccharides at the most
150. What substance cannot go through the
villi?
- Cellulose (dietary fiber)
151. What happens to the food products
that cannot go through the villi?
- They are mixed with other waste products
from the body, become hard and
concentrated feces.
152. Why are coliform bacteria necessary?
- They make vitamins that we need:
- Vitamin K, biotin, and B5
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153. Examples of organic wastes that are
left in the lumen are…?
- Urobilinogens and sterobilinogens
154. What is defecation reflex?
- Mass movements of material through
colon and rectum
155. What triggers the movement?
- Mass movement is triggered by distention
of the rectal walls.
156. What are coliforms?
Bacteria that normally inhabit the large
intestine.
157. Give example of one species of
coliform?
E. coli.
158. What is GALT?
Gut-associated lymphoid tissue which keep
harmful microorganism within the intestine
at a minimum level
159. What are the three phases of gastric
secretion?
160. When does the cephalic phase of
gastric secretion occur? What is the
purpose of the cephalic phase?
- Cephalic phase
- Gastric phase
- Intestinal phase
- Occurs before food enters the stomach. It
prepares the body for ingestion and
digestion.
161. What initiates the cephalic phase of
gastric secretion?
- Sight and thought of food, taste and smell
of food.
162. What part of the brain is stimulated by
the sight and thought of food?
- Cerebral cortex
163. What part of the brain is stimulated by
the taste and smell of food?
- Hypothalamus and medulla oblongata
164. What happens after the brain is
stimulated by sight, thought, taste, and
smell of food?
- The Vagus nerve (CN X) is stimulated, and
it releases acetylcholine (Ach).
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165. What happens to the acidity of the
stomach during the cephalic phase of
gastric secretion?
- Since the acidity is not reduced by food
yet, the high acid levels cause the D cells to
secrete somatostation.
166. What effect does somatostatin have
when the stomach has excess acidity?
- Somatostatin tells the G cells to stop
secreting gastrin.
167. What happens when the G cells stop
secreting gastrin?
- The parietal cells stop secreting HCl.
168. Where are G cells found?
In the stomach
169. What neurotransmitter does the vagus
nerve release when food arrives in the
stomach?
Gastrin-releasing peptide
170. What does gastrin-releasing peptide
do?
Activates G cells
171. What else activates G cells?
The presence of proteins in the stomach
172. What do G cells secrete?
G cells secrete the hormone, gastrin
173. What effect does gastrin have?
Gastrin makes the parietal cells secrete HCl
and the chief cells to secrete pepsinogen
174. What turns off gastrin secretion?
When there is enough acid in the stomach
175. What three things stimulate the
release of gastrin?
Stomach distension, Vagus nerve
stimulation, and the presence of proteins in
the stomach.
176. What two things inhibit the release of
gastrin?
Enough HCl in the stomach, and
somatostatin (growth hormone- inhibiting
hormone)
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177. Where are D cells located?
In the stomach, intestine, and Islets of
Langerhans in the pancreas
178. What is the function of D cells?
They either increase or decrease
somatostatin output
179. What causes the D cells to increase
somatostatin output?
Gastrin (from G-cells in the stomach)
180. What causes the D cells to decrease
somatostatin output?
Stimulation from the neurotransmitter, Ach
181. What is another name for
Somatostatin?
Growth hormone-inhibiting hormone.
182. What 4 gastrointestinal hormones does
it suppress?
Gastrin
Chylecystokinin (CCK)
Secretin
GIP
183. Does it suppress or increase the
release of pancreatic hormones?
Suppress
184. What hormones does it inhibit in the
pancreas?
Insulin and Glucagon
185. Does somatostatin slow down or speed
up the digestive process?
Slow down
186. How is the gastric phase stimulated?
By distension of the stomach, presence of
food in stomach and decrease in pH.
187. How long does the gastric phase last?
3-4 Hours
188. What two reflexes are stimulated by
gastric distention?
The long reflex and the myenteric reflexes.
189. What do the long and myenteric
reflexes activate?
The release of acetylcholine which
stimulates the release of more gastric juices.
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190. As proteins enter the stomach, what
do they bind to? What effect does this have
on pH in the stomach?
Hydrogen Ions, which raises the pH of the
stomach.
191. As the pH in the stomach rises, what
starts secreting?
G cells in the stomach secrete the hormone
gastrin, which stimulates parietal cells to
secrete gastric acid (HCl).
192. What other substances trigger the
release of gastric acid?
Acetylcholine and histamine.
193. The intestinal phase of gastric section
has what 2 opposing actions?
EXCITATORY and INHIBITORY.
194. When partially digested foods fill the
duodenum, what hormone is released by
the stomach?
GASTRIN
195. What reflex inhibits the Vagus nerve?
ENTEROYGASTRIC REFLEX
196. What is the direct effect of the
Enterogastric reflex?
makes the pyloric sphincter tighten
197. When the pyloric sphincter tightens,
what effect does it have?
prevents more food from entering the
duodenum
198. In what two ways are peptic ulcers
classified?
By region and by type
199. What are three types of peptic ulcers
as classified by region?
Duodenal, esophageal, and gastric ulcers.
200. Duodenal ulcers and gastric ulcers in
the body of the stomach are what type
classification?
TYPE 2
201. Which ulcer type is In the pyloric
region?
TYPE 3
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202. Which ulcer type is associated with
chronic aspirin use?
Type 5
203. What type of diabetes is called “adult
onset”? At what age does it occur
Type II usually occurs after age 40
204. What is the problem in people with
Type II diabetes?
All the cells in the body have a lowered
sensitivity to insulin; the insulin receptors on
the cell membranes are not working
properly, and the glucose is not transported
into the cell.
205. What causes Type II diabetes?
Obesity. A person who has extra energy
stored in their body will stop producing
insulin receptors on their cell membranes
because their cells do not need glucose.
206. How is Type 2 diabetes controlled?
Dietary changes and regular exercise
207. What are two pancreatic disorders?
Pancreatitis and pancreatic cancer
208. How is absorption of fat, proteins, and
carbohydrates affected without pancreatic
enzymes?
 60% fat not absorbed, causing steatorrhea
(fatty stools)
 30-40% protein and carbohydrates not
absorbed
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Organ
Pancreas
Region of the Organ
Acinar cells
Acinar cells
Substances
Amylase (enzyme)
Lipase (enzyme)
Function
Breaks down starch and carbohydrates into glucose
Breaks down fat into fatty acids
Acinar cells
Acinar cells
Protease enzymes (trypsin,
chymotrypsin,
carboxypeptidase)
Bicarbonate (not an enzyme)
Breaks down proteins into amino acids and also kills
intestinal parasites and bacteria
Raises pH in duodenum
Islet of Langerhans;
Alpha cells
glucagon (hormone)
Causes glycogenolysis, the process which breaks down
glycogen into glucose to raise blood glucose. Also causes
gluconeogenesis to make new glucose molecules
Islet of Langerhans;
Beta cells
insulin (hormone)
Removes glucose in bloodstream and brings it into cells.
Lowers blood glucose levels.
Islet of Langerhans;
Delta cells
Somatostatin (hormone)
Inhibits gastrin, insulin, and glucagon (inhibits digestive
system)
Liver
Bile (a detergent)
Salivary glands
Amylase (enzyme)
Stomach
Mucous (not an enzyme)
Protect the stomach lining
Prostaglandins (not an
enzyme)
Protect the stomach lining
Breaks down starch and carbohydrates into glucose
HCl (not an enzyme)
Allows Pepsinogen to be converted to pepsin, and it also
kills bacteria
Parietal cells
Intrinsic factor (not an
enzyme)
Allows Vit B12 to be absorbed, which is needed to make
RBCs. Without it, you get megaloblastic (pernicous)
anemia.
Chief cells
G cells
Pepsinogen --> pepsin
(enzyme)
Gastrin (hormone)
Breaks proteins into amino acids
Tells parietal cells to secrete HCl
Parietal cells
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Organ
Duodenum
Region of the Organ
K cells
Substances
Secretin (hormone)
Function
Tells pancreas to secrete bicarbonate
CCK (hormone)
Tells pancrease to secrete proteases, and tells gallbladder
to release stored bile (stimulates fat and protein
digestion)
GIP (hormone)
Tells pancreas to release insulin and also causes fat to be
broken down into fatty acids
Motilin (hormone)
Initiates perstalsis and tells Chief cells to secrete
pepsinogen
Maltase, Lactase, Sucrase
(enzymes)
Break down complex carbohydrates into glucose
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