MINISTRY OF PUBLIC HEALTH OF UKRAINE
BUKOVINIAN STATE MEDICAL UNIVERSITY
Approval on methodological meeting
of the department of pathophisiology
Protocol №
Chief of department of the pathophysiology,
professor
Yu.Ye.Rohovyy
“___” ___________ 2008 year.
Methodological Instruction
to Practical Lesson
Мodule 1 : GENERAL PATHOLOGY.
Contenting module 1. General nosology.
Theme2: Etiology. Pathogenesis.
Chernivtsi – 2008
1.Actuality of the theme. Due to continuous evolution organism has
adapted to normal atmosphere pressure. But in conditions of modern life man
more often encounters with action of changed atmosphere pressure. This is related
to production activity (fliers, spacemen, divers), sport (mountaineering). Action of
changed atmosphere pressure on organism is used in medicine for treatment
(barotherapy). It is important to know rapid change of atmosphere pressure causes
of the symptoms, which is called barotrauma. In modern of contemporary war
barotrauma can have wide spread owing to influence of shock wave.
2.Length of the employment – 2 hours.
3.Aim:
To khow external and internal causes of disease.
To be able: To analyse three variants interconnection of the cause and
pathogenesis:
1) Etiological factor initiates the pathologic process and then disappears, so
the pathogenesis develops without etiological factor (trauma, radiation).
2) The cause continues its action throughout all the period of the
development of the disease (infectious disease), as consequence the etiological
factor penetrates into pathogenesis, exist in it and influence it.
3) Persistence of the cause agent, which causes the disease, is delayed in
organism (healthy bacilli-carrier).
To perform practical work: To analyse the “vicious circle” in the
pathogenesis. Causes and consequences constantly change their places. The cause
(etiological factors) causes the pathologic reactions (process) and then these
reactions return to the first agent (etiological factor) and intensify it. So “vicious
circle” is formed in pathogenesis.
For example, if arterial pressure decrease it causes hypoxia and then vasomotor center depresses. It leads to the prolonged decrease of arterial pressure.
To analyse “the main stage” in pathogenesis.
The main stage of pathogenesis is the process, which initiates the
development of others. The time of elimination of the main stage of elimination of
the whole process. So, in diabetes mellitus “ the main stage “ of pathogenesis is
lack of insulin. Its elimination (introduction of the hormones) leads to the
disappearance of other manifestation of the disease (hyperglycemia, ketosis,
coma).
4. Basic level.
The name of the previous disciplines The receiving of the skills
1. histology
Gas composition of air and partial pressure
2. biochemistry
of oxygen. Functional units structure of
3. physiology
respiratory system, blood, blood circulation
system.Physical and chemical indexes of
gases
interchange
in
organism.
Neurohumoral regulation of breathing and
blood circulation.
5. The advices for students.
1.What is the general etiology?
Etiology is a study of the causes and conditions of the disease which provoke the
disease and determine its specific features.
2. Etiological factors: 1.biological (microbes, viruses, parasites); mechanical
(trauma); physical (atmosphere pressure, electric current, ionizing radiation, xrays, space flight factors ); chemical (drugs, narcotics, alcohol, acids and others);
psychical (emotional stress). The external groups of etiologic factors: Viruses,
Microorganisms, Alcohol, Trauma, Temperature, Medicines The internal groups
of etiologic factors: Heredity, Sex, Constitution
3. What is pathogenesis? Pathogenesis (from Greek "pathos" - suffering,
genesis — origin) is a study on mechanisms of the development and outcome of
the disease. Pathogenesis of every disease depends on the cause and resistance
(reactivity) of the human organism.
4.How does pathogenesis divide? (four periods of pathogenesis) . The
pathogenesis is a new complicated process in the organism with the two quite
opposite processes: 1) "the measure against the disease" (by I.Pavlov) — it means
the compensatory and protective reactions 2) "pathologic process proper"
So, the pathogenesis is a unity of opposites, which always fight (law of dialectics).
The doctor must find out pathologic process the proper and stimulate the
protection. There are four stages of pathogenesis: 1) latent period (incubation
period of the infectious diseases) 2) prodromal one 3) the period of expressed
manifestations 4) the outcome of the disease.
5. What is the connection between the cause and the pathogenesis?
There are three variants interconnection of the cause and pathogenesis: 1)
Etiological factor initiates the pathologic process and then disappears, so the
pathogenesis develops without etiological factor (trauma, radiation). 2) The cause
continues its action throughout all the period of the development of the disease
(infectious disease), as consequence the etiological factor penetrates into
pathogenesis, exist in it and influence it. 3) Persistence of the cause agent, which
causes the disease, is delayed in organism (healthy bacilli-carrier).
6. Vicious circle.
Causes and consequences constantly change their places. The cause (etiological
factor) causes the pathologic reactions (process) and than these reactions return to
the first agent (etiological factor) and intensify it. So "vicious circle" is formed m
pathogenesis For example, if arterial pressure decrease it causes the hypoxia and
than vasomotor center depresses. It leads to the prolonged decrease of arterial
pressure.
"VICIOUS CIRCLE"
7. What is the main stage in pathogenesis?
The main stage of pathogenesis is the process which initiates the development of
others. The time of elimination of the main stage is the time of elimination of the
whole process.
So, in diabetes mellitus the main stage of pathogenesis is lack of insulin. Its
elimination (introduction of the hormone) leads to the disappearance of other
manifestations of the disease (hyperglycemia, ketosis, coma).
8. Negative effect of changes of atmospheric pressure. A man feels the effect
of decreased atmospheric pressure during ascent on plane or in mountains, or the
pilots flying in nonhermetically sealed cabin.
The pathologic changes, occurring in it, are caused by two main factors:
a) decrease of partial pressure of oxygen in inspired air;
b) decrease of atmospheric pressure (decompression).
The clinical signs of decompression syndrome are: pain in the ears and frontal
sinuses because of expansion of air in these cavities, nasal bleeding, because of
bursts of small vessels. Bursting of alveoli and vessels causes the gas bubbles to
into the blood circulatory system (gas embolism, hypoxia, boiling of blood and
other liquids, especially at the height of 1900 m).
A man feels the effect of increased atmospheric pressure in water during diver’s
or caisson works.
The most important is the fact if of quick increase of atmospheric pressure
(hyperbaria) so the rupture of lung alveoli occurs and additional quantity of gases
dissolves in blood and tissues (saturation). Nitrogen plays a key-role in breathing
with the compressed air. The quantity of nitrogen in the body can sometimes
increase, especially in the organs, which contain a lot of lipids (nervous system).
The first manifestation is a light excitement, like euphoria, the next are the
phenomena of narcosis and intoxication.
Not only nitrogen is toxic, but also oxygen (hyperoxia) realizes its toxic effect a
little later. The hemoglobin molecule is blocked by oxygen and loses its ability to
carry out carbon dioxide. The result is that oxygemoglobin practically does not
dissociate and carbon dioxide is not removed.
Toxic effect of high concentration of oxygen is similar to the effect of radiation.
In both cases the formation of free radicals and peroxides with strong exudative
abilities causes affection of DNA and tissue enzymes.
The antioxidant therapy must be used, such as tocopherols, glutathione,
ubiquinone and others, which suppress free radical oxidation. Decompression can
be used which is a method of returning of the man into the conditions of normal
atmospheric pressure and the excretion of the excess quantity of dissolved gases
via blood and lungs (desaturation).
9. Pathogenic influence of electric current.
Mechanism: Electric energy is transformed into:
1. Mechanical tearing off tissues and bones and even part of the body
2. Thermal – temperature in place of penetration may be 120 °C and more –
than burns arise
3. Chemical – electrolysis may cause changes of biological potential of the
different cells.
10. The effect of ionizing radiation.
The rays of high energy (X- and g rays), a and b- particles, proton possesses the
ability to penetrate into the radiated environment and produce ionization.
5.1. Content of the theme. What is the general etiology? Etiological factors:
1.biological (microbes, viruses, parasites); mechanical (trauma); physical
(atmosphere pressure, electric current, ionizing radiation, x-rays, space flight
factors ); chemical (drugs, narcotics, alcohol, acids and others); psychical
(emotional stress). What is pathogenesis? How does pathogenesis divide? (four
periods of pathogenesis. What is the connection between the cause and the
pathogenesis? Vicious circle. What is “the main stage” in pathogenesis? Negative
effect of changes of atmospheric pressure. Pathogenic influence of electric current.
The effect of ionizing radiation.
5.2. Control questions of the theme:
1. What is the general etiology?
2. Etiological factors: biological (microbes, viruses, parasites); mechanical
(trauma); physical (atmosphere pressure, electric current, ionizing radiation, xrays, space flight factors ); chemical (drugs, narcotics, alcohol, acids and others);
psychical (emotional stress).
3. What is pathogenesis?
4. How does pathogenesis divide? (four periods of pathogenesis.
5. What is the connection between the cause and the pathogenesis?
6. Vicious circle
7. What is “the main stage” in pathogenesis?
8. Negative effect of changes of atmospheric pressure.
9. Pathogenic influence of electric current.
10. The effect of ionizing radiation.
5.3. Practice Examination.
Practice examination N 1-2 (1)
1. Find the faulty answer to the following: Pathogenic effect of natural
(lightning) electricity depends on: A. Permanency (constant, variable)B. Strength
C. Tension D. Direction E. Duration of penetration through the body F. Reactivity
of organism G. Heredity
2. What direction of electricity through the human body is the most
dangerous? A. Head B. Kidney C. Heart D. Liver
3. When the man is less sensitive to the electric current?
A. Under narcosis B. Tiredness C. Hypoxia D. Alcohol intoxication
4. The most resistant to electric current are all the below mentioned except:
A. External epidermal layer B.Tendons and bones C.Nerves D.Muscles E. Blood
F. Cerebrospinal fluid
The immediate cause of death in electrotrauma is respiratory standstill (5) and
cardiac arrest (6). Match the definition with its term.
A. Injury of the respiratory center B. Ventricle fibrillation C. Spasm of
coronary vessels D. Spasm of vertebral arteries, bringing blood to the respiratory
center E. Injury of the vasomotor center F. Increase of the nervous vagus tension
G. Laryngospasm H. Spasm of the respiratory musculature
Practice examination N 1-2 (2)
I. Give the description of each form of radiation disease:
A.The disturbance of hemopoiesis and blood system (lymphopenia,
thrombocytopenia) B. Anemia
C. Immune reactivity decrease D. Dysfunction of the alimentary tract, vomiting,
anorexia, diarrhea
E.Necrotic tonsillitis F.Hemorrhagic syndrome G.Sexual dysfunction H.Spasm
paralytic syndrome J. Shock K. Asthenia L. Trophic disorders
1. Acute form 2. Chronic form
II. What organs and systems are the most sensitive to the ionizing radiation?
A. Blood B. Brain C. Hemopoietic tissue D. Heart
III. The effect of ionizing radiation may lead to:
A. Tumors B. Leukosis C. Hereditary diseases D. Aging E. All of the above
are correct
IV. For each statement choose T (true) or F (false) in the list provided.
3. The first period of acute radiation disease (ARD) with duration from several
hours to 1-2 days is characterized by excitation, headache, instability of the
vegetative functions, lability of the arterial pressure and pulse.
4. Latent period (one week) is accompanied by leukopenia (progressing of
lymphocytopenia, development of granulocytopenia)
5. The third period is characterized by progressing leukopenia, anemia.
Hemorrhagic syndrome develops. Decrease of immunologic reactivity
6. Outcome of the ARD are multiple inflammatory processes (necrotic angina,
pneumonia, frontitis and others).
Practice examination N 1-2 (3)
For each statement concerning the influence of space flights on the human
body write T (true) or F (false) in the list provided.
1. The possibility of the human organism to adapt to this condition is absent.
2. The adaptation to weightlessness is based on active reorganization of some
systems on the new level of functioning.
3. The significant changes can be noted in the system of blood circulation. This
is load reorganization.
4. In weightlessness the locomotor apparatus is in the condition of functional
deafferentation.
5. The appearing changes of the muscles present not only atrophy without action
but also neurogenic dystrophy.
6. In weightlessness we can see intensified excretion of K+, ClЇ, Fe 2+, Na+, H2O,
Ca2+
7. Osteoporosis appears.
8. The mass of the skeleton and muscular tissue decreases, the signs of atrophy
appear.
9. The changes in muscles and bones are caused by hypokinesia.
10. After returning to the Earth the consequences of the weightlessness
disappear.
11. After returning to the Earth we can see the decrease of functional
possibilities of the systems counteracting gravity.
Literature:
1. Gozhenko A.I., Makulkin R.F., Gurcalova I.P. at al. General and clinical
pathophysiology/ Workbook for medical students and practitioners.-Odessa, 2001.P.11-27.
2. Gozhenko A.I., Gurcalova I.P. General and clinical pathophysiology/ Study
guide for medical students and practitioners.-Odessa, 2003.- P.5-26.
3. Robbins Pathologic basis of disease.-6th ed./Ramzi S.Cotnar, Vinay Kumar,
Tucker Collins.-Philadelphia, London, Toronto, Montreal, Sydney, Tokyo.-1999.