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ЗмістContent and Quantity of the Blood
HV = (Red Cell Volume Total blood Volume) 100
Changes in haemotocrite value (HV)
Plasma protein consistency
Clinical importance of Albumin – Globulin ratio (A/g ratio)
Importance of Electrolytes
Regulation of Secretion
Mechanisms which provide the constant pH level
Age features of physical and
Questions for self-control
Tests for self control
CHAPTER 2 Physiologies of Erythrocytes
Common functional characteristics of erythrocytes
V Plastic features of erythrocyte
VI Osmotic resistance of erythrocytes
MINISTRY OF HEALTH OF UKRAINE
MINISTRY OF EDUCATION AND SCIENCE OF UKRAINE
SUMY STATE UNIVERSITY
V.Yu. Garbuzova, L.А. Los, O.A. Obukhova
PHYSIOLOGY OF THE BLOOD
Is recommended by the Central methodological study
with higher education the Ministry of Health of Ukraine
Sumy State University
BBK 67.9 (4УКР) я7
Shevchuk V.G. – doctor of medical sciences, professor;
Samokhvalov V.G. – doctor of medical sciences, professor;
Mischenko I.V. - doctor of medical sciences, professor
Is recommended by the Central methodological study with higher education
the Ministry of Health of Ukraine as educational book
for students of higher education IV level accreditation
(letter № 23-01-25/114 from 28.10.2009)
G72 Physiology of the blood: educational book / V.Yu. Garbuzova, L.А. Los,
O.A. Obukhova – Sumy: Publisher SumSU. – 2010. – 165 p.
This teaching aid described in the tutorial material for self-preparing students to practical classes in physiology from the “Physiology of the blood”. Each theme contains basic information theoretic question to self, test questions and problems.
For students of institutions of the III - IV level of accreditation.
У навчальному посібнику викладений матеріал для самостійної підготовки студентів до практичних занять з фізіології з розділу “Фізіологія крові”. До кожної теми наведені основні теоретичні відомості, питання до самопідготовки, тестові питання і задачі.
Для студентів вищих медичних закладів III – IV рівнів акредитації.
Blood is used to transport substances and together with lymph and intercellular fluid belongs to the internal medium of the organism. With the help of well regulated constant content and properties of it, the internal medium provides comparably independent existent of the organism in conditions of the environment. Compounds of internal medium have common and differential physical and chemical properties. They can affect each other, and their state depends on activities of various systems of the organism.
System of the blood is the variety of executive organs (blood, which is circulated and stored; organs of blood formation and blood degradation) and mechanisms of regulation (nervous and humoral), activity of which is directed on keeping the adequate changes of blood compounds to provide adaptive reactions.
Blood participates in transport of substances, helps the excretion of metabolic products, it provides protection from antigens and non-protein factors, affects the regulation of different functions of the organism.
Chapter “Physiology of the blood” is important in preparing the medical doctor of any specialty, because the state of internal medium describes all processes in organism, which characterize homeostasis, homeokinesis and adaptive reactions when changes in internal medium and co-operation of the organism with the environment.
Teach chapter “Physiology of the blood” is necessary for learning the next chapters of physiology and other subjects, for example pathological physiology and all clinical medically-specified subjects.
CHAPTER 1 Physical and Chemical Properties of the Blood
Blood is one of many functional systems of the organism. Together with nervous system blood unties organs in entire organism. At the same time they define the term – proper blood system or physiological blood system (PBS).
The contents of PBS are:
Functions of the Blood
Functions of the blood are important and various. Practically all of them are associated with the circulation of the blood in blood vessels. That is why the main function of the blood is transport function. There are several types of it:
Besides, pathogenic factors are transported with blood: microorganisms, toxins, tumor cells. Transport of the last one will lead to the development of metastasis of malignant tumor.
Except the transport function, blood plays an important role in maintaining homeostatic features of the organism. That is why the second important function of the blood is homeostatic function. There are several types of it:
The third, important function of the blood is creative function. Macromolecules, which are transported with blood, perform intercellular information transferring, which provides regulation of intracellular processes of protein synthesis, keeping the level of cell differentiation, renovation and maintenance of tissue structure.
Peripheral blood – is the blood, which circulates in vessels and it is stored.
The volume of circulating blood (VCB) is 6-8% of body weight of adult human or 70 – 75 ml/kg of the body weight (approximately 4 – 6 liters).
VCB is an important physiological constant. VCB depends on:
Normal VCB value is normovolemia, increased VCB – hypervolemia, decreased VCB – hypovolemia.
Peripheral blood consists of plasma (55 – 60%) and formed elements (40 – 45%) fig. 1.1.
Percentage volume of the formed elements is called hematocrit. In normal state hematocrit value is HV almost completely depends on the quantity of erythrocytes in the blood, because its volume is nearly 99% of the volume of all formed elements of the blood. Only in some forms of leucosis, due to development of anemia and increase in quantity of circulating leucocytes, the part of the last ones in hematocrit value increases.
Hematocrit is defined by Wintrobe method. 2 ml of the blood is put in special centrifugal glass, then add anticoagulant to it and turn it for 10 minutes with 1000 turns per minute. Blood cells, mass of which is higher than plasma will settle down in the bottom. Due to plasma are lighter in weight than erythrocytes, they will form thin white layer between erythrocytes and plasma.
Figure. 1.1 – Compaund of the blood
Other method for determination of haemotocrite value is microtechique: Blood sample is withdrawn in a heparinized capillary glass tube of small size. Both ends are waxed. The tube is put with other similar tubes in a special centrifuge and rotated for few minutes. The tube is then removed after separation of red cells from plasma and put on a special scale to read the haematocrite value.
Hematocrit value depends on:
The increase of hematocrit can lead to increase of blood stickness and that means to increase of the load on heart, disorders of blood circulation.
1) HV is increased in:
a) polycythaemia: due to increased number of R. B. Cs as in high altitude and in the newly born infants;
b) dehydration: due to decreased plasma volume as in severe vomiting and diarrhea.
2) HV is decreased in:
a) anemias: due to decreased R. B. Cs. count;
b) Overhydration: as in renal diseases or after intravenous infusion of large amounts of fluids (fig. 1.2).
Uses of haemotocrite value:
2) determination of blood volume and renal blood flow;
3) calculation of certain blood indices;
4) follow up of cases of shock.
Functional importance of blood plasma components
Figure 1.2 – Haematocrit in the normal person and partients with anaemia and polycythaemia
Main components of blood plasma are:
Importance of Water
Importance of Proteins
There are specific and non-specific transport proteins. Not-specific – are able to bind different substances and transport those (most of albumins transport hormones, calcium). Specific – transport only one kind of substances. For example, cerulloplasmin – ions of cuprum (Cu), transferrin – ions of iron (Fe), haptoglobulin – bilirubin.
which with peripheral tissues, are used for the formation of proper, specified for the organ proteins. Proteins are the source of energy. When breaking down 1 g of protein in the organism 4,1 kkal.
Trophic function of proteins is used clinically when disorder of natural way of nourishment, in parenteral nourishment, when protein suspensions are injected in bloodstream.
a) Na proteinate +H2CO 3 NaHCO3 + Proteinic acid.
b) Na proteinate + lactic acid Na lactate + Proteinic acid.
Lactic acid (strong acid) is converted to proteinic acid (weak acid).
For example, kinins and angiotensin.
Ponc= 25 – 30 mmHg. 80% of oncotic pressure is made by albumins (molecule of albumin has small size and in volume of plasma, its quantity is the highest).
Role of oncotic pressure in redistribution of water in the organism (fig. 1.3):
C a p i l l a r y
Arterial part Venous part
I n t e r c e l l u l a r l i q u i d
Рhp = 3 mmHg Рhp = 3 mmHg
Рop = 4,5 mmHg Рop = 4,5 mmHg
Figure 1.3 – Redistribution of water in the capillaries
Wall of capillaries is permeable to small molecules and water. That is why osmotic pressure in blood plasma and in intercellular liquid is almost equal. Big molecules, first of all protein molecules, can not pass through the capillary wall. That’s why there is gradient of protein concentration (oncotic pressure gradient - Ponc) between plasma and intercellular liquid. Ponc inside capillary is higher than in intercellular liquid. Hydrostatic pressure – pressure of the liquid on the capillary wall (from one side blood is making pressure on capillary wall, from other side – intercellular liquid), it also plays important role in redistribution of the water. Hydrostatic pressure of the blood is higher, than hydrostatic pressure of intercellular liquid.
Water exchange occurs in two ways:
The direction of the water movement is defined by the filtrative pressure (Pf).
Pf = (Phbp + Pop) – (Php + Pobp)
Phbp – hydrostatic pressure of the blood;
Pop – oncotic pressure of the intercellular liquid;
Php – hydrostatic pressure of the intercellular liquid;
Pobp – oncotic pressure of the blood.
If Pf >0 – filtration occurs.
If Pf <0 – reabsorbtion occurs.
Increasing of the Phbp and Pop leads to filtration, increasing of the Php and Pobp leads to reabsorbtion.
In the arterial end of the capillary:
Pf = (32,5 + 4,5) – (25 + 3) = 9 mmHg – filtration occurs, water is transited to the tissue.
As the blood passes in the capillary, in the result of transition of the water to the tissue, hydrostatic pressure decreases. In the middle of the capillary Pf = 0 and water transition stops.
In the venous end of the capillary:
Pf = (17,5 + 4,5) – (25 + 3) = - 6 mmHg – reabsorbtion occurs, water passes into the capillary.
At the beginning of the capillary approximately 0,5% of blood plasma passes to the tissues. Pf in the arterial part of the capillary (Pf = 9 mmHg) is higher than in the venous part (Pf = - 6 mmHg), that is why the bloodstream returns not the whole 100% of the liquid, but nearly 90%. 10% are excreted through the lymphatic vessels.
This pressure values may vary in different organs and it depends on organ activity. Described mechanism of filtration – reabsorbtion is called Starling’s mechanism.
Changes in any of the parameters may cause disorder in filtration and reabsorbtion correlation.
For example, the decrease in protein concentration in blood plasma will lead to the decrease of the reabsorbtion, delay of the water in intercellular medium and development of the intercellular oedema. This can happen during starvation (cachexy oedemas); when pathological processes in kidneys, in the consequence of which proteinuria can occur and loss of proteins (nephrotic oedemas); when disorder in albumin synthesis by liver (hepatic oedemas); when allergic and inflammatory processes, when there is the increase of vessel wall permeability and other plasma proteins are leaving to the intercellular space (membranogenic oedemas) and other.
|А. Los, O. A. Obukhova|
У навчальному посібнику викладений матеріал для самостійної підготовки студентів до практичних занять з фізіології з розділу “Фізіологія...
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