Hypoxia. (Subject 7)
1. HypoxiaJanuary 20, 2017
2. Hypoxia classificationExogenous
3. Hypoxia classificationDue to time of development
– Fulminant (immediate) –several seconds
– Acute – several minutes (cardiac arrest).
– Subacute – several hours or days
– Chronic – months and years.
4. Hypoxia classificationDue to prevalence of clinical symptoms:
– local and general.
Due to the severity of pathological process:
critical (lethal) hypoxia.
5. Exogenous (hypoxic) hypoxia hypobaric typeatmospheric pressure+ partial oxygen
pressure in the air
Mountain sickness factors: low partial
pressure of oxygen, low barometric
pressure, physical loading, cooling,
increased exposure to UV rays.
Altitude sickness factors: low barometric
pressure and low partial pressure of oxygen
6. Exogenous (hypoxic) hypoxia normobaric typeNormal atmospheric pressure +
oxygen % in the air:
- in small rooms with bad ventilation
(elevators, mines, mineshafts);
- in divers, when there are problems
with aqualung function;
- incorrect conduction of artificial lungs
ventilation during surgical operations.
7. Exogenous (hypoxic) hypoxiaLow oxygen
in the air
in the blood
in the blood
8. Exogenous (hypoxic) hypoxiaABB –
in the blood
in the air
in the blood
in the tissues
9. Respiratory hypoxiaCauses
of gases diffusion
in the lungs
10. Respiratory hypoxiaAlveolar hypoventilation reasons:
Obstructive violations (lung edema, tumors
or foreign bodies in the lumen of bronchi
Restrictive violations (chronic inflammatory
or sclerotic processes in the lungs and in the
Disturbances of respiratory regulation (toxic
substances poisoning, brain trauma).
11. Respiratory hypoxiaDisturbances of lungs blood supply heart failure, decreased circulating blood
volume (after blood loss).
Disturbances of gases diffusion in lungs
chronic inflammatory diseases of the lungs,
Blood indices: low oxygen, high CO2, low pH
12. Circulatory hypoxiaCauses
13. Circulatory hypoxia - systemicCirculatory hypoxia systemic
Decrease of heart activity - myocardial
Hypovolaemia - severe blood loss,
dehydration of the organism after burns,
Vascular disorders (low vascular tone) shock, collapse, aldosterone deficiency.
14. Circulatory hypoxiaLocal type of circulatory hypoxia insufficient blood supply of the organ
or tissue (ischemia) or the difficulty of
venous outflow (venous hyperemia,
Blood indices: normal oxygen in arterial
blood, low oxygen in venous blood,
low pH (acidosis).
15. Hemic hypoxiaAnemic type – accompanying different
Inactivation type - poisoning with CO,
nitrates, sulfonamides and other substances
that yield in methemoglobin formation
Blood indices: low O2 in arterial and
venous blood, non-gaseous acidosis.
16. Hemic hypoxiaThe reasons of anemia:
depression of erythropoiesis.
17. Hemic hypoxiaCarbon monoxide poisoning:
CO has the affinity to Hb 300 times higher than
Carboxy-Hb (HbCO) is formed (stable
Symptoms: drowsiness and headache,
unconsciousness, respiratory failure, and death.
18. Histotoxic hypoxiaThe inability of cells to utilize oxygen
tissue poisoning (alcohol, narcotics,
biological oxidation enzymes inhibition
and the disturbance of their synthesis;
the damage of membrane structures
of the cell.
19. Histotoxic hypoxiaCyanide poisoning
Cyanide ions bind to the Fe atom of
cytochrome C oxidase
The ATP synthesis stops.
Nervous system and the heart are
20. Histotoxic hypoxiaDisturbance of respiratory enzymes
synthesis results from vitamins deficiency
(B group vitamins, pantothenic acid).
Damage of mitochondrial membranes
and other cellular elements (radiation injury,
over-heating, intoxication, infection,
Blood indices: the pressure, saturation and
content of O 2 in blood are near normal.
21. Histotoxic hypoxiaDissociation of oxidation and
phosphorylation processes in
– energy is dispersed as a heat.
– ATP synthesis is low.
The factors: hormones of thyroid gland,
excess of Ca, toxins.
22. Overload hypoxiaOccur during physical overload of certain organ or
It is observed in skeletal muscles and myocardium.
Blood indices: arterial and venous hypoxemia and
Local heart hypoxia may transform to secondary
general circulatory hypoxia
In the excessive muscular work - bloodflow in the
muscles is increased
ischemia of other
23. Substrate hypoxiaDeficiency of the substrate to be
oxidized - glucose
Carbohydrate starvation and hypoxia of
insulin-dependent tissues often occur
during diabetes mellitus.
24. Combined hypoxiaIt is a combination of 2 and more main
types of hypoxia.
25. Combined hypoxiaRespiratory
of heart and vessels
26. Disturbances in the Organs and Physiological SystemsNervous system –
1. emotional and motion excitation,
2. disturbances of reflex activity and
regulation of breathing and blood
3. loss of consciousness and convulsions.
Heart and vessels – tachycardia,
arrhythmia, low BP.
27. Disturbances in the Organs and Physiological SystemsLungs - irregular breathing; decreased
diffusion of oxygen from the alveolar
air to blood.
Liver (chronic hypoxia) - disturbance of
all kinds of metabolism, inhibition of
detoxication, decreased synthesis of
28. Disturbances in the Organs and Physiological SystemsGIT organs (chronic hypoxia) violation of appetite, inhibition of
peristalsis and secretion, development
of erosions and ulcers.
Immune system (chronic hypoxia) low functional activity of the immune
cells and innate immunity factors.
29. Adaptation to hypoxiaThe reactions of urgent adaptation
(protective-adaptive) manifest in
(compensatory) - during long-term or
repeating hypoxic effects.
30. Urgent adaptationThe reason of adaptation - lack of
energy supply due to low ATP
amount (lack of biological oxidation).
Respiratory system - blood
oxygen and CO2 irritate
chemoreceptors. This result in the
increase of the alveolar ventilation.
31. Urgent adaptationHeart – tachycardia, heart stroke
volume and minute blood volume.
Vessels - centralization of bloodflow
(dilation of the brain and heart
arterioles with simultaneous
constriction of the arterioles in others
tissues and organs).
32. Urgent adaptationBlood - activation of RBC outflow from the
bone marrow and blood depot (liver,
Increased affinity of Hb to oxygen and the
degree of oxyHb dissociation in the tissues.
Tissues systems of biological oxidation anaerobic glycolysis, the activation of
33. Adaptation to hypoxiaUrgent reactions - activation of the
oxygen transport to the tissues.
Permanent compensation activation of biological oxidation and
structural changes of organs and
systems that are transporting oxygen.
34. Permanent adaptationLungs - increased surface of alveoli, number
of capillaries, rate of gases diffusion
through alveoli to vessels.
Respiratory muscles - hypertrophy and
increased working capacity.
Heart - the number of myocardial fibers,
capillaries and nerves is increased. of
heart stroke volume and minute volume.
35. Permanent adaptationNumber of the vessels in all organs and
tissues is increased.
Blood – increased blood cells number due to
– Chronic lack of oxygen causes the activation of
erythropoietin synthesis in kidneys.
Metabolic processes :
– decrease of metabolism intensiveness;
– high efficiency of anaerobic glycolisis;
– prevalence of anabolic processes in the cells.
36. Clinical application of hypoxiaIntermittent hypoxia - repeated episodes
of hypoxia interspersed with normoxic
periods (Interval Hypoxic Trainings)
Hypoxic episodes are created by exposure to
natural high altitude, sojourns in hypobaric
chambers or by breathing hypoxic gas
mixtures in normobaric conditions.
37. Clinical application of hypoxiaInterval Hypoxic Training is used for the
treatment of bronchial asthma, chronic
obstructive pulmonary diseases, coronary
heart disease, arterial hypertension,
neurocirculatory asthenia, neurodermitis,
diabetes mellitus II type.
The method is effective to increase physical
and mental working capacity.
The counter-indications are: all acute somatic
and infectious diseases.
38. Clinical application of hypoxiaAdaptation to hypoxia provides
resistance to other stress factors
Adaptation to hypoxia is characterized
with structural and functional
changes in many organs and tissues.
Body resistance is increased to
hypothermia, overheating, physical