Physiological system of blood. Functional importance of blood plasma components

Physiological system of blood. Physiological system of blood. Functional importance of blood Functional importance of blood

plasma components.plasma components.

BLOODBLOOD

Blood volume is 8% of body weightBlood volume is 8% of body weightAverage adult has 5 liters of blood:Average adult has 5 liters of blood:

The The blood volume of an adult correlates with blood volume of an adult correlates with his or her (fat-free) body mass and his or her (fat-free) body mass and amounts to 4–4.5 L in women and 4.5–5 L in men of 70 kg BW.amounts to 4–4.5 L in women and 4.5–5 L in men of 70 kg BW.

Blood, lymph and interstitial fluid are components of internal Blood, lymph and interstitial fluid are components of internal environment of the organism.environment of the organism.Properties of blood as a specific tissue:Properties of blood as a specific tissue:a) fluid;a) fluid;b) circulated;b) circulated;c) all components of the blood are performed and destroyed c) all components of the blood are performed and destroyed in special organs (but do not in blood itself).in special organs (but do not in blood itself).

Blood executes all transport functions: transport of Blood executes all transport functions: transport of gases (Ogases (O22, CO, CO22), nutritious, heat, hormones, defensive ), nutritious, heat, hormones, defensive substances.substances.

PHYSICO-CHEMICAL PROPERTIES PHYSICO-CHEMICAL PROPERTIES OF BLOODOF BLOOD

1.1. Composition of the blood:Composition of the blood: plasma and formed plasma and formed elements: erythrocytes, leucocytes, platelets.elements: erythrocytes, leucocytes, platelets.

Plasma constitutes 55 – 60% of the volume of the Plasma constitutes 55 – 60% of the volume of the blood. Formed elements constitute 40 – 45%.blood. Formed elements constitute 40 – 45%.

99% are red blood cells, remainder white blood cells and blood platelets99% are red blood cells, remainder white blood cells and blood platelets

HAEMATOCRIT – special graduate capillary tube HAEMATOCRIT – special graduate capillary tube for centrifugation of the blood sample using to for centrifugation of the blood sample using to separate plasma and formed elements.separate plasma and formed elements.

The The hematocrit hematocrit is an indicator of anemia, polycythemia, and other is an indicator of anemia, polycythemia, and other conditions.conditions.

hematocrit (cell volume/ blood volume):hematocrit (cell volume/ blood volume):

in males – 0.40–0.54; in females: 0.37–0.47in males – 0.40–0.54; in females: 0.37–0.47

2. AMOUNT OF BLOOD.2. AMOUNT OF BLOOD.

The total amount of the blood of the body The total amount of the blood of the body is form 6 – 7,5% of the body weight.is form 6 – 7,5% of the body weight.

It is determined by It is determined by indicator dilution indicator dilution methodmethod (a colloid dye may be used to (a colloid dye may be used to determine volume of plasma or determine volume of plasma or radioactive phosphorus may be used to radioactive phosphorus may be used to determine volume of erythrocytes).determine volume of erythrocytes).

3. VISCOSITY.3. VISCOSITY.

If the viscosity of water is 1 unit the If the viscosity of water is 1 unit the viscosity of blood plasma is about 2 units viscosity of blood plasma is about 2 units and the viscosity of whole blood 5 units. and the viscosity of whole blood 5 units. Therefore viscosity depends of Therefore viscosity depends of concentration of plasma proteins and concentration of plasma proteins and haemotocrit.haemotocrit.

The specific gravity of whole blood is The specific gravity of whole blood is 1.050 to 1.060.1.050 to 1.060.

4. COMPOSITION OF BLOOD PLASMA:4. COMPOSITION OF BLOOD PLASMA:

- water – 92%;water – 92%;

- proteins – 7-8% (albumin – 4.5%, proteins – 7-8% (albumin – 4.5%, globulin – 2-3.5%, fibrinogen – 0.4%);globulin – 2-3.5%, fibrinogen – 0.4%);

- mineral substances – 0.9%;mineral substances – 0.9%;

- glucose – 4.4-6.6 mmol/L.glucose – 4.4-6.6 mmol/L.

5.5. SIGNIFICANCE OF MINERAL SUBSTANCES:SIGNIFICANCE OF MINERAL SUBSTANCES:

a)a) they provide normal osmotic pressure;they provide normal osmotic pressure;

b)b) they are components of buffer systems;they are components of buffer systems;

individual ions provide normal excitability individual ions provide normal excitability of cells (K, Na, Ca, Cl), contractile and of cells (K, Na, Ca, Cl), contractile and secretary functions (Ca, Mg).secretary functions (Ca, Mg).

6. OSMOTIC PRESSURE.6. OSMOTIC PRESSURE.

OsmosisOsmosis is the net diffusion of water from a region is the net diffusion of water from a region of high water concentration to one of lower concentration of high water concentration to one of lower concentration (through the cell membrane).(through the cell membrane).

Osmotic pressure is equal to the amount of Osmotic pressure is equal to the amount of hydrostatic pressure that must be applied to prevent the hydrostatic pressure that must be applied to prevent the net diffusion of water through the semipermeable net diffusion of water through the semipermeable membrane. The osmotic pressure of blood can be membrane. The osmotic pressure of blood can be measured by osmometer or by the cryoscopic method measured by osmometer or by the cryoscopic method (measuring blood freezing point that is lower of zero to (measuring blood freezing point that is lower of zero to 0.56 – 0.58◦C). This parameter is called “depression of the 0.56 – 0.58◦C). This parameter is called “depression of the blood”. blood”.

Osmotic pressure of human blood corresponds to 7.6 atm.Osmotic pressure of human blood corresponds to 7.6 atm.

OSMOTIC PRESSURE is important for regulation of OSMOTIC PRESSURE is important for regulation of water exchange between intracellular and water exchange between intracellular and extracellular spaces. These spaces are separated extracellular spaces. These spaces are separated by a selective cell membrane, which is highly by a selective cell membrane, which is highly permeable to water but not to most of the permeable to water but not to most of the electrolytes. Composition of intra- and extracellular electrolytes. Composition of intra- and extracellular fluid is different (intracellular fluid contains only small fluid is different (intracellular fluid contains only small amount of Na, Cl, Ca; large amount of K, amount of Na, Cl, Ca; large amount of K, phosphates, some amount of Mg, SOphosphates, some amount of Mg, SO44; large amount ; large amount of proteins). Osmotic pressure of all body cells is the of proteins). Osmotic pressure of all body cells is the same as that of the extracellular fluid and blood same as that of the extracellular fluid and blood plasma (because of each diffusion of water).plasma (because of each diffusion of water).

Immersion of erythrocytes in a solution of NaCl Immersion of erythrocytes in a solution of NaCl of higher concentration than blood plasma of higher concentration than blood plasma (hypertonic solution) shows that cells loss water (hypertonic solution) shows that cells loss water and shrink.and shrink.

Immersion of erythrocytes in a solution of NaCl Immersion of erythrocytes in a solution of NaCl of lower concentration than blood plasma of lower concentration than blood plasma (hypotonic solution) shows that cells increase in (hypotonic solution) shows that cells increase in volume (swell) and finally be disrupted (osmotic volume (swell) and finally be disrupted (osmotic haemolysis).haemolysis).

The excretory organs (kidneys, sweat glands), The excretory organs (kidneys, sweat glands), maintain maintain constant level of osmotic pressureconstant level of osmotic pressure..

INTRACELLULAR EDEMA:INTRACELLULAR EDEMA:

– Depression of the cell metabolic systems Depression of the cell metabolic systems (hypoxia, acidosis) – depression of ion (hypoxia, acidosis) – depression of ion pumps – excess Na-ions inside the cell – pumps – excess Na-ions inside the cell – osmosis of water into the cell – swell and osmosis of water into the cell – swell and death of tissues.death of tissues.

– Inflammation – increases cell membrane Inflammation – increases cell membrane permeability – diffusion of Na-ions (and permeability – diffusion of Na-ions (and other ions) inside the cell – osmosis of water other ions) inside the cell – osmosis of water into the cell – swell and death of tissues.into the cell – swell and death of tissues.

7. BLOOD pH.7. BLOOD pH. Active reaction of blood (pH) depends of Active reaction of blood (pH) depends of concentration of hydrogen (H+) hydroxyl (OH-) concentration of hydrogen (H+) hydroxyl (OH-) ions. It is parameter of extremely great ions. It is parameter of extremely great importance (since metabolism normally occurs importance (since metabolism normally occurs only at a definite reaction).only at a definite reaction).

pH index of arterial blood is 7.4;pH index of arterial blood is 7.4;

pH index of venous blood is 7.35 (owing to the pH index of venous blood is 7.35 (owing to the large content of COlarge content of CO22).).

Limits of blood pH change (compatible with life) Limits of blood pH change (compatible with life) are 6.8 to 8.0. However a persistent shift of the are 6.8 to 8.0. However a persistent shift of the normal pH of 0.1 or 0.2 can be fatal too. normal pH of 0.1 or 0.2 can be fatal too.

Constant level of pH is maintained byConstant level of pH is maintained by

(a)(a) the buffer systems of the tissues, blood the buffer systems of the tissues, blood plasma and erythrocytes (that connect plasma and erythrocytes (that connect hydrogen and hydroxyl ions) and hydrogen and hydroxyl ions) and

(b)(b) the activity of the excretory organs (that the activity of the excretory organs (that eliminate hydrogen and hydroxyl ions eliminate hydrogen and hydroxyl ions from the organism).from the organism).

There are three primary systems that regulate pH to There are three primary systems that regulate pH to prevent acidosis and alkalosis:prevent acidosis and alkalosis:

The chemical acid-base buffer systems, which act The chemical acid-base buffer systems, which act within a fraction of a second;within a fraction of a second;

The respiratory center, which regulates the removal The respiratory center, which regulates the removal of COof CO22 (and therefore H (and therefore H22COCO33). This mechanism acts ). This mechanism acts within a few minutes. It is the second line of defense.within a few minutes. It is the second line of defense.

Kidneys, which can excrete either acid or alkaline Kidneys, which can excrete either acid or alkaline urine. This mechanism is the slowest but the most urine. This mechanism is the slowest but the most powerful of acid-base regulatory systems. It acts powerful of acid-base regulatory systems. It acts within hours to several days. It is the third line of within hours to several days. It is the third line of defense.defense.

BUFFER SYSTEMS OF BLOOD AND TISSUESBUFFER SYSTEMS OF BLOOD AND TISSUES

1. Bicarbonate buffer system1. Bicarbonate buffer system (H(H22COCO3 3 and and NaHCONaHCO33).).

This is extracellular buffer system (buffer system of This is extracellular buffer system (buffer system of the blood).the blood).

HH22COCO33 + NaOH = NaHCO + NaOH = NaHCO33 + H + H22OO

NaHCONaHCO33 + HCl = H + HCl = H22COCO33 + NaCl + NaCl

Kidneys eliminate excess of the sodium Kidneys eliminate excess of the sodium bicarbonate;bicarbonate;

Lungs eliminate COLungs eliminate CO22 (H (H22COCO33 = H = H22O + COO + CO22).).


2. Phosphate buffer system (NaH2. Phosphate buffer system (NaH22POPO44 and and NaNa22HPOHPO44).).

This is intracellular buffer system, renal tubular fluidThis is intracellular buffer system, renal tubular fluidbuffer system and buffer system of the blood buffer system and buffer system of the blood plasma.plasma.

NaHNaH22POPO44 +NaOH = Na +NaOH = Na22HPOHPO44 + H + H22OO NaNa22HPOHPO44 + HCl = NaH + HCl = NaH22POPO44 + NaCl + NaCl

Kidneys eliminate excess of sodium Kidneys eliminate excess of sodium hydrophosphate or sodium dihydrophosphate.hydrophosphate or sodium dihydrophosphate.


3. Hemoglobin buffer system (HHb and 3. Hemoglobin buffer system (HHb and KHHbOKHHbO22).).

This is buffer system of the erythrocytes.This is buffer system of the erythrocytes.

KHHbOKHHbO22 + H + H22COCO33 = HHb + KHCO = HHb + KHCO33 + O + O22

This is most powerful buffer system of This is most powerful buffer system of the blood.the blood.


4. Protein buffer system.4. Protein buffer system.

This is intracellular buffer system and This is intracellular buffer system and buffer system of the blood plasma.buffer system of the blood plasma.

8. PLASMA COLLOID OSMOTIC PRESSURE8. PLASMA COLLOID OSMOTIC PRESSURE(ONCOTIC PRESSURE)(ONCOTIC PRESSURE)

Plasma proteins create only 1/200 part of total osmotic Plasma proteins create only 1/200 part of total osmotic pressure (about 28 mm Hg). It is called oncotic pressure. pressure (about 28 mm Hg). It is called oncotic pressure.

The proteins are the only substances in the plasma The proteins are the only substances in the plasma that do not diffuse through the capillary membrane (small that do not diffuse through the capillary membrane (small amount of proteins do diffuse into the interstitial fluid but amount of proteins do diffuse into the interstitial fluid but are soon removed from this space by way of the lymph are soon removed from this space by way of the lymph vessels). The most amounts of plasma protein remain in vessels). The most amounts of plasma protein remain in capillaries and keep large amount of water.capillaries and keep large amount of water.Proteins: 7-8 mg/mL in the plasma (oncotic pressure 28 Proteins: 7-8 mg/mL in the plasma (oncotic pressure 28 mm Hg);mm Hg);2-3 mg/mL in the interstitial fluid (oncotic pressure 8 mm 2-3 mg/mL in the interstitial fluid (oncotic pressure 8 mm Hg);Hg);0.5 per cent of the plasma in the flowing blood filters out 0.5 per cent of the plasma in the flowing blood filters out through the capillary wall. There are more filtration of fluid through the capillary wall. There are more filtration of fluid into the interstitial space than reabsorbtion. into the interstitial space than reabsorbtion.

ANALYSIS OF THE FORCE CAUSING ANALYSIS OF THE FORCE CAUSING FILTRATIONFILTRATION AT AT THE ARTERIAL END OF THE CAPILLARY:THE ARTERIAL END OF THE CAPILLARY:

Force tending to move fluid outward:Force tending to move fluid outward: Force tending to move fluid inward:Force tending to move fluid inward:

Capillary blood pressureCapillary blood pressure 30 mm Hg30 mm Hg Plasma oncotic pressurePlasma oncotic pressure

28 mm Hg28 mm Hg

Negative interstitial Negative interstitial

pressurepressure 3 mm Hg3 mm Hg

Interstitial oncotic Interstitial oncotic pressurepressure

8 mm Hg8 mm Hg

Total outward forceTotal outward force 41 mm Hg41 mm Hg

Summation of force:Summation of force:

Outward 41 mm HgOutward 41 mm Hg Inward 28 mm HgInward 28 mm Hg

NET OUTWARD FORCE 13 mm HgNET OUTWARD FORCE 13 mm Hg

ANALYSIS OF THE FORCE CAUSING ANALYSIS OF THE FORCE CAUSING REABSORPTIONREABSORPTION AT THE ARTERIAL END OF THE CAPILLARY: AT THE ARTERIAL END OF THE CAPILLARY:

Force tending to move fluid outward:Force tending to move fluid outward: Force tending to move fluid inward:Force tending to move fluid inward:

Capillary blood pressureCapillary blood pressure 10 mm Hg10 mm Hg Plasma oncotic pressurePlasma oncotic pressure

28 mm Hg28 mm Hg

Negative interstitial Negative interstitial

pressurepressure 3 mm Hg3 mm Hg

Interstitial oncotic Interstitial oncotic pressurepressure

8 mm Hg8 mm Hg

Total outward forceTotal outward force 21 mm Hg21 mm Hg

Summation of force:Summation of force:

Outward 21 mm HgOutward 21 mm Hg Inward 28 mm HgInward 28 mm Hg

NET OUTWARD FORCE 7 mm HgNET OUTWARD FORCE 7 mm Hg

EXTRACELLULAR EDEMA:EXTRACELLULAR EDEMA:

Increase capillary blood pressureIncrease capillary blood pressure..

1. Excessive kidney retention of salt and water:1. Excessive kidney retention of salt and water:a)a) acute or chronic kidney failure;acute or chronic kidney failure;b)b) mineralocorticoid excess.mineralocorticoid excess.

2. High venous pressure:2. High venous pressure:a)a) heart failure;heart failure;b)b) venous obstruction;venous obstruction;c)c) failure of venous pumps (paralysis of skeletal muscles; immobilized failure of venous pumps (paralysis of skeletal muscles; immobilized

part of body; failure of venous valves).part of body; failure of venous valves).

3. Decrease arteriolar resistance:3. Decrease arteriolar resistance:a)a) excessive body heat;excessive body heat;b)b) insufficiency of sympathetic nervous system;insufficiency of sympathetic nervous system;c)c) vasodilator drugs.vasodilator drugs.


Decrease plasma proteinsDecrease plasma proteins..

1.1. Loss of proteins in urine (nephritic syndrome).Loss of proteins in urine (nephritic syndrome).

2.2. Loss of proteins from denuded skin areas (burns, Loss of proteins from denuded skin areas (burns, wounds).wounds).

3.3. Failure to produce proteins:Failure to produce proteins:a)a) liver diseases;liver diseases;b)b) serious protein or caloric malnutrition.serious protein or caloric malnutrition.

4. Starvation.4. Starvation.


Increased capillary permeabilityIncreased capillary permeability..

1.1. Immune reactions (histamine).Immune reactions (histamine).

2.2. Toxins or bacterial infections.Toxins or bacterial infections.

3.3. Vitamin deficiency (vit. C).Vitamin deficiency (vit. C).

4.4. Prolong ischemia.Prolong ischemia.

5.5. Burns.Burns.


Blockage of lymph returns.Blockage of lymph returns.

Cancer.Cancer. Infection (filaria nematodes).Infection (filaria nematodes). Surgery.Surgery. Abnomality of lymphatic vessels.Abnomality of lymphatic vessels.

Red Blood Synthesis and AgingRed Blood Synthesis and Aging

Erythrocytes or RBC are synthesized in response to Erythrocytes or RBC are synthesized in response to erythropoetin erythropoetin (kidney hormone)(kidney hormone)

The The mature cells lack nucleimature cells lack nuclei and are small, biconcave disks. They no and are small, biconcave disks. They no longer can divide.longer can divide.

Cells consist 1/3 of Cells consist 1/3 of hemoglobin (Hb)hemoglobin (Hb), the protein that carries , the protein that carries oxygenoxygen in in blood.blood.

RBC lack mitochondria and produce ATP through glycolysis only.RBC lack mitochondria and produce ATP through glycolysis only.

Red Blood Cell DestructionRed Blood Cell Destruction• Damaged or Damaged or worn cells ruptureworn cells rupture in the spleen or liver. in the spleen or liver.• In the spleen or liver,In the spleen or liver, macrophages macrophages phagocytize and destroy cells. phagocytize and destroy cells.• HbHb is broken down into is broken down into globin and hemeglobin and heme which decomposes into which decomposes into

biliverdinbiliverdin. . • The The heme groupheme group has a central has a central ironiron element to which oxygen binds. element to which oxygen binds.• Biliverdin is converted to Biliverdin is converted to bilirubin bilirubin and excreted in and excreted in bile bile via thevia the

gallbladdergallbladder..• IronIron is carried on transferrin to the liver were it is stored as ferritin. is carried on transferrin to the liver were it is stored as ferritin.

Erythropoiesis – RBC productionErythropoiesis – RBC production

Red blood cells (RBC) are called erythrocytes.Red blood cells (RBC) are called erythrocytes.

They are produced in They are produced in red bone marrow.red bone marrow.

Average life span is 120 days.Average life span is 120 days.

When When oxygen concentrations in the blood are lowoxygen concentrations in the blood are low, , erythropoietin is released from the erythropoietin is released from the kidneykidney..

Erythropoietin operates in a negative feedback Erythropoietin operates in a negative feedback

mechanism to maintain RBC mechanism to maintain RBC homeostasishomeostasis..

NORMAL BLOOD ANEMIC BLOODNORMAL BLOOD ANEMIC BLOOD

anemia: a condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume – see APLASTIC ANEMIA, HYPERCHROMIC ANEMIA, HYPOCHROMIC ANEMIA, MEGALOBLASTIC ANEMIA, MICROCYTIC ANEMIA, PERNICIOUS ANEMIA, SICKLE-CELL ANEMIA; compare OLIGOCYTHEMIA

Blood PlateletsBlood Platelets• ThrombocytesThrombocytes• Arise from Arise from megakaryocytes megakaryocytes in the red bone marrowin the red bone marrow• Platelets are small and lack a nucleusPlatelets are small and lack a nucleus• Help repair broken blood vesselsHelp repair broken blood vessels• Release Release serotoninserotonin

White Blood CellsWhite Blood CellsWhite Blood Cells (WBC) are called White Blood Cells (WBC) are called leukocytesleukocytes..

They protect against disease.They protect against disease.

Granulocytes: Granulocytes: granular cytoplasm; neutrophils, eosinophils, granular cytoplasm; neutrophils, eosinophils, basophilsbasophils

Agranulocytes: Agranulocytes: lack cytoplasmic granules; monocytes, lack cytoplasmic granules; monocytes, lymphocyteslymphocytes

NeutrophilsNeutrophilsGranules stain light purple in Granules stain light purple in acid-base combination stainsacid-base combination stainsFirst white blood cells that First white blood cells that arrive at place of infectionarrive at place of infectionThey constitute 54% to 62% They constitute 54% to 62% of the leukocytes.of the leukocytes.Older neutrophils are called Older neutrophils are called segs (segments) or segs (segments) or polymorph nuclear polymorph nuclear leukocytesleukocytes due to nuclear due to nuclear appearanceappearanceYounger neutrophils are Younger neutrophils are called bandscalled bands

EosinophilsEosinophils

Contain coarse deep red Contain coarse deep red staining granulesstaining granules

Nucleus has two lobesNucleus has two lobes

Active during moderate Active during moderate allergic reactionsallergic reactions

Defend against parasitic Defend against parasitic worm infectionworm infection

Constitute 1% to 3% of Constitute 1% to 3% of leukocytes leukocytes

BasophilsBasophils

Granules stain deep blue Granules stain deep blue in basic stainin basic stain

Nuclei have two lobesNuclei have two lobes

Migrate to damaged Migrate to damaged tissuetissue

Release Release histaminehistamine to to promote inflammation promote inflammation and and heparin heparin to inhibit to inhibit blood clottingblood clotting

Constitute less than 1% Constitute less than 1% of leukocytesof leukocytes

AgranulocytesAgranulocytes

Monocytes: largest cells; leave bloodstream and become macrophages; 3% to 9% of the leukocytesLymphocytes: T cells and B cells; important in immunity and antibody production; 35% to 33% of leukocytes

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Physiological system of blood. Functional importance of blood plasma components