- •13. Disturbances of the peripheral blood circulation
- •13.1. Name the main forms of the local disturbances of blood circulation:
- •13.2. What is arterial hyperemia?
- •13.3. What functional changes and clinical attributes characterize arterial hyperemia?
- •13.4. What factors can be a cause of arterial hyperemia? What mean the physiological and pathological arterial hyperemia?
- •13.5. Name the main mechanisms of the pathological arterial hyperemia development.
- •13.6. What is the essence of the neurotonic mechanism of development of the arterial hyperemia ?
- •13.7. Explain the neuroparalytic mechanism of development of the arterial hyperemia.
- •13.8. What humoral factors can be the cause of development of arterial hyperemia?
- •13.9. What is the role of endothelium of blood vessels in development of arterial hyperemia?
- •13.10. Name possible outcomes of arterial hyperemia.
- •13.11. What is venous hyperemia?
- •13.12. What factors can be the cause of venous hyperemia?
- •13.13. What attributes display venous hyperemia?
- •13.14. What local and common violations can be consequence of venous hyperemia?
- •13.15. What is ischemia?
- •13.16. What attributes are typical for ischemia?
- •13.17. Name the main types of ischemia depending on the reason and mechanisms of its occurrence.
- •13.18. How are defined the character of metabolic, functional and structural disturbances in a tissue in case of its ischemia?
- •13.19. What consecutive stages characterize the pathogenesis of alterations in ischemic tissues?
- •13.20. What is stasis?
- •13.21. Name the main variants of stasis and their reasons.
- •13.22. What is the thrombosis?
- •13.23. Name three major factors, promoting thrombosis formation (Virhov’s triad).
- •13.24. What phases is the process of blood clot forming consists of? What is their essence?
- •13.25. What negative consequences can thrombosis formation in pathology have?
- •13.26. What is embolism?
- •13.27. What kinds of embolism are assigned?
- •13.28. Name principal causes of embolism exogenous.
- •13.29. Name the principal causes of embolism of endogenous origins.
- •13.31. What is the essence of a phenomenon called "sludge"?
- •13.32. How the exchange of water between plasma of blood and an interstitial liquid is carried out?
- •13.33. How does hydrostatic and oncotic pressure of blood and an intercellular liquid changes influence on intensity of processes of a filtration-reabsorption of water in capillaries?
- •13.34. What is the insufficiency of lymphokinesia? Name its main forms.
13.31. What is the essence of a phenomenon called "sludge"?
Sludge concerns to the intravascular violations of microcirculation connected to change of reologic properties of blood. Major factors of such changes are violations of suspension stability of blood, and also increase of its viscosity.
The main features of blood at sludge are sticking to each other of erythrocytes, leukocytes and trombocytes, increase in viscosity of blood that complicates its movement on microvessels. Thus the current of blood is sharply slowed down and reminds moving silt on a river bed.
Depending on the sizes of units of blood cells, character of their contours and density of packing erythrocytes can be distinguished the following types of sludge: classical (the large sizes of units, rough outlines of contours and dense packing of erythrocytes), dextrin (various size of units, spherical outlines, dense packing of erythrocytes) and amorphous granular (huge amount of fine units as the granules, consisting only from several erythrocytes).
13.32. How the exchange of water between plasma of blood and an interstitial liquid is carried out?
On a basis of an exchange of water between plasma of the blood and interstitial liquid, there are three mechanisms:
1. Bilateral diffusion. It has the greatest value. Its speed is so great, that at passage of blood through capillaries the liquid of plasma has time to exchange completely 40 times with a liquid of intercellular space.
Speed of diffusion of water through the common exchange surface of capillaries is 60 l per minute, or 85 000 l per day.
2. A filtration-reabsorption. It is the mechanism of redistribution of water which is determined by two factors: а) hydrostatic pressure of blood and an intercellular liquid; b) oncotic pressure of plasma of blood and of interstitial liquid. The ratio between these factors is such, that in an arterial part of a capillary there is a filtration of water, and in a venous part it reabsorption.
Speed of a filtration through the common exchange surface of capillaries of an organism makes 14 ml per 1 minute, or 20 liters per day, and speed reabsorption is 12,5 ml per 1 minute, or 18 liters per day.
3. Microvesicular transport. It is the mechanism of active transport through endothelium of capillaries. It bases on the phenomenon of endocytosis (pinocytosis, micropinocytosis).
13.33. How does hydrostatic and oncotic pressure of blood and an intercellular liquid changes influence on intensity of processes of a filtration-reabsorption of water in capillaries?
The direction of movement of water and intensity of processes of a filtration-reabsorption are determined by degree of effective filtration pressure (Pef): Pef = (Phb + Pot) – (Pob + Pht)
Where Phb and Pob - hydrostatic and oncotic pressure of blood; Pht and Pot - hydrostatic and oncotic pressure of the interstitial liquid.
In states of norm in the arterial end of capillaries Рef = 9 mm of Hg and the liquid passes from blood in a tissue (filtration), and on venous site Рef = - 6 mm of Hg, therefore the liquid passes back from tissues in capillaries (reabsorption).
The filtration of water increases, and reabsorption decreases at increase in hydrostatic pressure of blood and oncotic pressure of an intercellular liquid, and also at reduction oncotic pressure of plasma of blood and tissue hydrostatic pressure.
The filtration of water decreases, and reabsorption grows at reduction of hydrostatic pressure of blood and oncotic pressure of an intercellular liquid, and also at increase of oncotic pressure of plasma of blood and hydrostatic pressure of a liquid of intercellular spaces.