Download PHYSIOLOGY OF DIGESTIVE SYSTEM

STATE GOVERNMENT-FUNDED EDUCATIONAL INSTITUTION
OF HIGHER PROFESSIONAL TRAINING
UNDER THE MINISTRY OF HEALTH OF THE RUSSIAN FEDERATION
“VOLGOGRAD STATE MEDICAL UNIVERSITY”
DEPARTMENT OF NORMAL PHYSIOLOGY
GUIDE BOOK
PRACTICAL MANUAL IN NORMAL PHYSIOLOGY
PHYSIOLOGY OF DIGESTIVE SYSTEM
For 2nd year students of MD-programme
Name:
Group:
Volgograd, 2012
УДК
Physiology of digestive system. Guide book. Practical manual in normal physiology.
– Volgograd: VolgSMU, 2012. – 12 p.
Compiled by: Klauchek S. V., Lifanova E. V., Khvastunova I. V., Kudrin R. A.,
Akhundova R. E., Doletsky A. N., Schmidt S. A.
Approved by the Central Methodology Board of the Volgograd State Medical University.
This manual summarizes the practical tasks of human physiology of digestive system.
It caters for teachers and students in the English-speaking medium of higher medical
educational institutions.
© Volgograd State Medical University, 2012.
2
CONTENT
Practical class 1. Principles of alimentary processes regulation. Digestion in
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the mouth and in the stomach. Regulation of these processes
Practical class 2. Digestion in the small intestine. Bile, its composition and
9
participation in digestion. Digestion in the large intestine. Intestinal motility
and its regulation. Physiology of the liver. Antitoxic function of the liver.
Gastrointestinal hormones
Practical class 3. Concluding class devoted to the themes “Metabolic rate and
energy expenditure. Thermoregulation” “Food and nutrition. Vitamins”,
“Physiology of the digestive system” (intermediate oral examination).
3
11
Practical class 1. Principles of alimentary processes regulation. Digestion in the mouth and in
the stomach. Regulation of these processes.
15.
16.
17.
Questions for discussion
Physiological basis of hunger and satiety. Physiology of digestion.
Elementary functional anatomic considerations. The main items in the study of the physiology of the digestive system.
Functional anatomy of the digestive system. The essence of digestion and classification of
digestive processes.
Nerve supply of the gastrointestinal tract (GIT). Gastrointestinal tract reflexes.
Principles of regulation of alimentary processes.
Digestion in the mouth. Functional anatomy of the salivary glands.
Mouth and its role in digestion. Esophagus. Mastication.
Salivary glands. Composition and functions of saliva.
Mechanism and control of salivary secretion. Deglutition.
Swallowing. Lower esophageal sphincter.
Motor disorders of the esophagus (achalasia, aerophagia, intestinal gas).
Functional anatomy of stomach. Digestion in stomach.
Functions of stomach. Some important cells in the gastric glands.
Composition and functions of gastric juice and mechanism of secretion. Control of gastric
secretion.
Four phases of gastric secretion. Emotion and gastric secretion.
Gastric motility and emptying.
Regulation of gastric motility and emptying.
1.
2.
3.
Practical works
Studying of operations on the animals used for researches of digestive functions.
Splitting of starch by enzyme of the saliva.
Studying of secretion of gastric juice on bread, meat and milk.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Books recommended
Ganong W. F. Review of Medical Physiology. 20th ed; McGraw-Hill Companies, Inc.,
2001. – P. 453-462, 472-480.
2.
Guyton A. C., Hall J. E. Textbook of Medical Physiology, 12th ed; W. B Saunders, 2005. –
P. 718-737.
1.
Practical work 1. Studying of operations on the animals used for researches of
digestive functions.
Objective: studying of advantages and disadvantages of some well known and traditional
operations in digestive physiology.
Technique.
1. Sham feeding . The esophagus is divided in the neck and the two ends are brought to the
surface of the neck. Now, when the animal feeds, food comes out through the wound and does not
reach the stomach.
In this animal, if a concomitant gastric fistula (which is a permanent hole made through the
anterior abdominal wall and anterior wall of the stomach, so that the cavity of the stomach
communicates with the exterior through the hole) be made various studies can be made. For
example, during sham feeding the secretion of the stomach (psychic juice) can be collected through
the fistula. That, in this animal, vagotomy abolishes the psychic phase of gastric secretion can be
shown, proving, that the psychic juice depends upon the presence of intact vagus nerves.
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Figure 1. Sham feeding.
Result:
Conclusion:
2. Pavlov pouch . This was devised by the great Russian physiologist Ivan Pavlov in 1898.
This is a pouch, cut out from the body of the stomach (fig.) in such a way that the cavity of the
pouch is separated from the main cavity of the stomach by double layers of mucous membrane. The
pouch however retains its nerve and blood supply intact. The pouch communicates with the exterior
by a permanent fistula made through the anterior abdominal wall.
Food may be eaten and it will be seen now that the pouch is also secreting. Thus, gastric
juice which is secreted as a result of stimulus by food and yet is not contaminated by food, can be
collected.
Figure 2. Pavlov pouch.
Result:
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Conclusion:
3. Heidenhein pouch is a denerved pouch, the pouch having no communication with the
parent cavity. Heidenhain pouch also communicates with the exterior by fistula and gastric
secretions collected from it.
Presence of food, particularly the partially digested protein in the original portion of
stomach, evokes secretion from this (Heidenhein) pouch, (which has no neural or direct
communication with the original part) proving that the stimulus to the pouch cannot be mediated by
nerves but must be mediated via blood, i. e., it is a chemical (gastrin) coming via the arterial supply
to the Heidenhain pouch. Similarly, histamine or pentagastrin can evoke secretion in a Heidenhain
pouch. The secretion of the pouch is uncontaminated by the food.
Figure 3. Heidenhain pouch.
Figure 4. Comparative characteristic of Pavlov pouch and Heidenhein pouch. (A) –
Innervated Pavlov pouch. (B) Vagally denervated Heidenhein pouch. (C) This shows Heidenhein
pouch during operation. (D) – This shows cannula position at the end of operation.
Result:
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Conclusion:
Practical work 2. Amylolysis by the enzyme of saliva.
Objective: prove that amylase of saliva split the starch to saccharides (dextrins and maltose)
under body temperature. Remember that amylase of saliva acts only on boiled starch.
Technique. Take 4 test-tubes; put 6 ml of 1 % boiled starch into 3 of them, put 6 ml of raw
starch into the fourth test-tube. Put 1 ml of distilled water into the first test-tube; put 1 ml of saliva
into the second and fourth; put 1 ml of well boiled saliva into the third one.
Put the test-tubes into the thermostat with the temperature 37-38° for 5-10 min. Divide the
contents of test-tubes into two portions; make qualitative reactions on starch and saccharides.
Qualitative reaction on starch: put 1-2 drops of fluid iodine solution into the examined
liquid. You can see blue staining in the first, third and fourth test-tubes; it indicates the existence of
the starch. There is no staining in the second test-tube.
Qualitative reactions on saccharides: put 3 ml 10 % NaOH and 1 ml 1% CuS0 4 into the
test-tubes with the examined liquid; heat it and indicate brown staining in the second test-tube (reaction on saccharides). Write down the results and make a conclusion.
Result:
№ of
Mixed components
testtube
1.
6 ml of boiled 1 ml of distilled
starch
water
2.
6 ml of boiled 1 ml of saliva
starch
3.
6 ml of boiled 1 ml of boiled
starch
saliva
4.
6 ml of
1 ml of saliva
unboiled starch
1. Qualitative reaction on starch
2. Qualitative reactions on glucose
Conclusion
1.
2.
1.
2.
1.
2.
1.
2.
1.
2.
1.
2.
1.
2.
1.
2.
Conclusion:
Practical work 3. Studying the gastric juice secretion on bread, meat and milk.
Objective: convince of the adaptive nature of the gastric gland secretion.
Technique: using tables and 3 crayons make 2 graphs: curves of the gastric juice secretion
and its digestion volume using equal quantity of meat, bread and milk.
Determine what are the differences between the gastric juice secretion and its digestion
volume using meat, bread and milk for food (quantity, duration, acidity, maximum secretion by the
hour).
Analysis of curves of the gastric juice secretion on meat, bread and milk.
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Food is an adequate stimulus for gastric secretion. The secretion reaction of the stomach
becomes apparent in the functional adaptation of gastric glands to various foods. Individual
adaptation of the secretory apparatus of the stomach to different food depends on the quality of food
product, its quantity and dietary habits.
Albuminous food is the most effective secretion agent. Proteins and products of their
digestion have the most strong secretion effect. The strong secretion of the gastric juice starts by the
second hour after eating meat. Prolonged meat diet leads to the increase of the gastric secretion on
all food stimuli, increase of acidity and digestion volume of the gastric juice.
Carbohydrate food (bread) – is the most weak secretion agent. There are a few chemical
agents of secretion in the bread; that is why the peak of gastric secretion is seen by the first hour
(reflex secretion), then it decreases steeply and then it keeps at the same level for a long time.
Prolonged carbohydrate diet decrease acidity and digestion volume of the gastric juice.
The action of the fats of milk on the gastric secretion consists of two stages:
braking and existent. That is why the peak of gastric secretion is seen just by the end of the third
hour. Prolonged fat diet increases the gastric secretion on food stimulus due to the second stage.
The digestion volume of the gastric juice after the fat diet is lower then after the meat diet but is
higher then after the carbohydrate food. Thus you can see the indexes of gastric juice secretion on
meat, bread and milk.
INDEX/LEVEL
MAXIMUM
MEDIUM
MINIMUM
Quantity of the gastric
juice
Meat
Bread
Milk
Prolongation of
secretion
Bread
Meat
Milk
Acidity of the gastric
juice
Meat
Milk
Bread
Digestion volume
Bread
Meat
Milk
Write down the results and make a conclusion about the dependence of the quantity of the
gastric juice, its acidity and proteolytic activity on quantity and consistence of eaten food.
Result:
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Conclusion:
Practical class 2. Digestion in the small intestine. Bile, its composition and participation in digestion. Digestion in the large intestine. Intestinal motility and its regulation. Physiology of the
liver. Antitoxic function of the liver. Gastrointestinal hormones.
25.
26.
27.
28.
Questions for discussion
Composition and function of pancreatic juice.
Mechanism of secretion of pancreatic juice.
Control of secretion of pancreatic juice.
Anatomic considerations of the liver. Functions of the liver.
Functional anatomy of the liver and the biliary tract.
Functions of the liver. Antitoxic function of the liver.
Composition of liver bile and gall bladder bile.
Functions of gall bladder. Functions of bile.
Secretion and excretion of bile. Control of secretion and control of excretion.
Synthesis of plasma proteins. Bile.
Bilirubin metabolism and excretion. Jaundice. Other substances conjugated by glucuronyl
transferase. Other substances excreted via bile.
Composition and properties of bile. Functions of the gallbladder. Regulation of biliary secretion.
The effects of cholecystectomy. Visualizing the gallbladder. Gallstones.
Digestive and absorptive functions of the small intestine.
Anatomic considerations of the small intestine.
Succus entericus: (i) composition and its functions; (ii) control of succus entericus secretion.
Cavital and membrane hydrolysis of nutrients in the small intestine.
Digestion and absorption of carbohydrate, protein and fat. Absorption of water, minerals and
vitamins.
Movements of the small intestine.
Digestion in the large intestine. Microflora of the large intestine.
Anatomic considerations of the colon.
Motility and secretion of the colon. Movements of the large intestine. Defecation.
Small intestinal and colon transit time. Mechanisms of absorption of proteins, carbohydrates, lipids in the colon. Absorption in the colon.
Feces. Intestinal bacteria.
Blind loop syndrome.
Dietary fiber.
Defecation.
The effects of colectomy. Constipation. Megacolon. Diarrhea.
1.
2.
Practical works
Digestion of protein by gastric juice.
Bile action on the fats.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
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Books recommended
Ganong W. F. Review of Medical Physiology. 20th ed; McGraw-Hill Companies, Inc.,
2001. – P. 481-496.
2.
Guyton, A. C., Hall, J. E. Textbook of Medical Physiology, 12th ed; W.B Saunders, 2005. –
P. 738-769.
1.
Practical work 1. Digestion of protein by the gastric juice.
Objective: determine the optimality conditions of pepsin action.
Technique. put into 6 test-tubes equal quantity of cut frog's muscle (fibm). Then put the
gastric juice in the first and in the second test-tubes; boiled gastric juice – into the third test-tube;
the solution of pepsin in water – into the fourth test-tube; the solution of pepsin in soda – into the
fifth test-tube; weak hydrochloric acid (0,5 %) - int the sixth test-tube. Put the second test-tube into
the bottle with ice, and the others – into thermostat with the temperature 37-40° C for 40 min. Then
take out the test-tubes and carry out the Biuret test. Put 10 drops of caustic soda and 5 drops of
blue vitriol to the solution.
You'll see blue and violet staining if there are proteins in the solution. Products of protein
digestion – albumose and peptones – give red staining. Complete the table.
Write down the results and make a conclusion about the optimally conditions of pepsin
action.
Result:
№ of
Mixed compounds
test-tube
1.
Protein; 2 ml of the
gastric juice
2.
Protein; 2 ml of the
gastric juice
3.
Protein; 2 ml of the
boiled gastric juice
4.
Protein; 2 ml of the
solution of pepsin in
water
5.
Protein; 2 ml of the
solution of pepsin in
soda
6.
Protein; 2 ml of 0,5
% hydrochloric acid
Conditions of carrying
out the experiment
37-40° C, 40 min.
(thermostat)
-1-0° C, 40 min. (bottle
with ice)
37-40° C, 40 min.
(thermostat)
37-40° C, 40 min.
(thermostat)
Biuret test
Conclusion
37-40° C, 40 min.
(thermostat)
37-40° C, 40 min.
(thermostat)
Conclusion:
Practical work 2. Bile action on the fats.
Objective: get acquainted with the bile action on fat filtration and emulsification.
Technique: filters, put in the funnels, moisten with bile (the first one) and with water (the
second filter). Put the funnels into the vials and pour fats into them.
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Fat filtrates rather quickly through the filter moisten with bile, and doesn't go through the
second filter.
Put 3 ml of bile, 0,5 ml of soft oil and 1 ml of water into the third vial, shake it up
thoroughly. You'll get trice emulsion.
Write down the results and make a conclusion.
Results:
Conclusion:
Practical class 3. Concluding class devoted to the themes “Metabolic rate and energy expenditure. Thermoregulation”, “Food and nutrition. Vitamins”, “Physiology of the digestive system” (intermediate oral examination).
1.
2.
3.
4.
5.
6.
1.
2.
3.
1.
2.
3.
4.
5.
6.
7.
8.
Questions for discussion
(Metabolic rate and energy expenditure. Thermoregulation)
Bomb calorimeter and calorific values of different items of food. Methods for determining
metabolic rate: (a) direct calorimetry; (b) indirect calorimetry: (i) respiratory quotient; (ii)
energy equivalent of utilized oxygen; (iii) Benedict-Roth spirometer (close circuit method);
(iv) open circuit method.
Values of metabolic rate. Basal metabolic rate: (i) definition; (ii) normal values; (iii) factors
determining metabolic rate; (iv) applied physiology.
Importance of thermoregulation. Normal body temperature. Sources of heat & channels of heat
loss.
Mechanism of thermoregulation in exposure to cold.
Mechanism of thermoregulation in a hot environment.
Applied physiology: fever, antipyretics, pyrogens, heat stroke, heat exhaustion, hypothermia.
Questions for discussion
(Food and nutrition. Vitamins)
Importance of food. Principles of dietetics.
Balanced diet. Some common foods. Applied physiology. Dietary standards for man.
Vitamins and its significance in nutrition. Vitamins. Classification. role of vitamins.
Questions for discussion
(Physiology of the digestive system)
Study of the physiology of the digestive system. Nerve supply of the gastrointestinal tract
(GIT). Gastrointestinal reflexes.
Functional anatomy of the salivary glands.
Composition and functions of saliva.
Mechanism and control of salivary secretion. Applied physiology.
Functional anatomy of the stomach.
Composition and functions of gastric juice and mechanism of gastric secretion.
Control of gastric secretion.
Functional anatomy of the digestive system. Gastrointestinal hormones.
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9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
Mouth and its role in digestion. Esophagus. Mastication.
Salivary glands. Composition and functions of saliva.
Mechanism and control of salivary secretion.
Swallowing. Lower esophageal sphincter. Motor disorders of the esophagus (achalasia,
aerophagia, intestinal gas).
Functional anatomy of the stomach. Digestion in the stomach. Functions of the stomach.
Some important cells in the gastric glands.
Composition and functions of gastric juice and mechanism of secretion.
Control of gastric secretion. Four phases of gastric secretion. Emotion and gastric secretion.
Pepsinogen secretion. HCl secretion. Functions of HCl. Regulation of gastric secretion.
Gastric motility and emptying. Regulation of gastric motility and emptying.
Peptic ulcer. Other functions of the stomach.
Composition and function of pancreatic juice.
Mechanism of pancreatic juice secretion.
Control of pancreatic juice secretion.
Functional anatomy of the liver and the biliary tract.
Composition of liver bile and gall bladder bile. Functions of the gall bladder.
Functions of bile. Secretion and excretion of bile. Control of secretion and control of excretion.
Digestive and absorptive functions of the small intestine. Duccus entericus: (i) composition
and its functions; (ii) control of succus entericus secretion. digestion and absorption of carbohydrates, proteins and fats. Absorption of water, minerals and vitamins.
Mastication. Deglutition. Movements of the stomach.
Movements of the small intestine. Movements of the large intestine. Defecation.
Anatomic considerations of the pancreas. Composition and properties of pancreatic juice.
Regulation of pancreatic juice secretion.
Anatomic considerations and functions of the liver. Synthesis of plasma proteins. Bile.
Composition and properties of bile. Functions of the gallbladder. Regulation of biliary secretion. Effects of cholecystectomy. Visualizing the gallbladder. Gallstones.
Anatomic considerations of intestinal mucus. Intestinal motility (characteristics of the types
of contraction).
Regulation of intestinal secretion. Malabsorption syndrome.
Adynamic ileus. Mechanical obstruction of the small intestine.
Anatomic considerations of the colon.
Motility and secretion of the colon.
Small intestinal and colon transit time. Mechanisms of absorption of proteins, carbohydrates, lipids. Absorption in the colon. Feces. Intestinal bacteria.
Blind loop syndrome. Dietary fiber. Defecation.
Effects of colectomy. Constipation. Megacolon. Diarrhea.
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