Transcript 17 Physiology of red blood cells. Erythron. Respiratory pigments

Blood system firstly was proposed by Lung
in 1936.
It consist of
- blood circulated through the blood
circulatory system
- blood forming organs
- blood destroying organs
- regulatory apparatus.
Blood is a fluid connective tissue.
Blood consist of
- plasma
- blood cells:
1. erythrocytes,
2. leucocytes,
3. platelets.
1. Breathing function of blood.
2. Trophic function of blood.
3. Excretory function of blood.
4. Hormonal regulation.
6. Temperature regulation.
7. Maintaining the acid-base balance of tissues.
8. Supporting the water-electrolytic balance.
9. Homeostasis function.
10. Protecting the body from bacteria and other
organisms that can cause diseases or other abnormal
conditions.
Transport of:
Gases, nutrients, waste
products
Processed molecules
Regulatory molecules
Regulation of pH and osmosis
Maintenance of body
temperature
Protection against foreign
substances
Clot formation
In adult in normal blood, relative to total body
weight, is 6.8%. Newborns - 15%.
Part of the blood is in the depot:
liver - 20%, in the skin, subcutaneous vascular
plexus - up to 10%, in the spleen - up to 1.5-2%
of blood.
Deposited blood in comparison with blood
circulating in the vessels is 10-20 times slower
than blood cells.
Human blood smear
X 500
Erythrocytes
In men – 4,0-5,1 Tera/L; in women –
3,7-4,7 Tera/L.
The quantity of erythrocytes may be
increase – in pregnancy, in physical
training, mental work, in newborn or
decrease.
Leukocytes - 4-9 Giga/L.
The number of leukocytes can increase –
physical work, emotional load, in
newborn, inflammation or decrease.
Platelates - 180-320 Giga/L.
Human erythrocytes nuclear-cells that are
shaped like concave discs
4,5-10,5 microns in
diameter (average
diameter of erythrocyte
7,55 m). With this form of
erythrocyte, its surface is
greater than it would be in
spherical form.
Quantitative parameters of erythrocytes
and their changes
“Erythron" introduced in 1936, Castle and Minot to refer to the
all quantity of red blood cells in the body.
Reduce the number of red blood cells called erythropenia.
Increasing the number of red blood cells is called polycythemia.
Under physiological conditions, polycythemia can be hereditary
and acquired (for example, when staying in the mountains)
Transport function. Red blood
cells carry: O2, CO2, NO,
adsorbed proteins, drugs,
physiologically active
substances.
Provide acid-base balance.
Maintaining the ionic
composition of the plasma.
Hemostatic.
Production of Erythrocytes:
Erythropoiesis
In adults, red blood cells are formed in the red bone marrow of flat
bones nuclear stem cells, which goes through several stages :
Common progenitor cell → uncommitted stem cell → committed stem
cell → erythroblast (is the first cell , which can be morphologically
identifiable ) → pronormoblast → early (basophilic) normoblast →
intermidiate (polychromatorhylic) normoblast → late (eosinophilic)
normoblast → reticulocyte → erythrocyte.
Bone marrow produces an hour about 1010 mature erythrocytes.
For the formation of erythrocyte need:
1. iron ;
2. vitamin B12 ;
3. B9 folic acid ;
4. vitamin C;
5. vitamin B6 ;
6. Vitamin B2 ;
Regulation of erythropoiesis carried out by neural and humoral
mechanisms, sympathetic innervation stimulates hematopoiesis
and parasympathetic - brakes.
Of great importance is the regulation of erythropoiesis
erythropoietin. Hematopoiesis is enhanced by hormones front
of the pituitary gland, adrenal glands, thyroid gland. Male sex
hormones stimulate, increasing the sensitivity of bone marrow
to erythropoietin, and women - inhibit erythropoiesis.
The body formed substances that inhibit erythropoiesis inhibitors of erythropoiesis. Their content increases with the
number of red blood cells, which do not meet the needs of the
tissues for oxygen. Inhibitors of erythropoiesis lengthen cycle
division erythroid cells, they inhibit the synthesis of
hemoglobin.
Regulation and Requirements for
Erythropoiesis
Circulating erythrocytes – the number remains
constant and reflects a balance between RBC
production and destruction
Too few red blood cells leads to tissue hypoxia
Too many red blood cells causes undesirable blood
viscosity
Erythropoiesis is hormonally controlled and
depends on adequate supplies of iron, amino
acids, and B vitamins
Water – 90 %
Solids – 10 %
Inorganic chemicals:
sodium, calcium, potassium, magnesium, chloride,
bicarbonate, phosphate, sulfate – 0,9 %
Organic chemicals:
Proteins: serum albumin, serum globulin, fibrinogen – 8 %
Others: – 1,1 %
Nonprotein nitrogenous substances: urea, uric acid, creatine,
creatinine, ammonium salts, amino acids
Nonnitrogenous substances: glucose, fats, cholesterol
hormones
Gases: oxygen, carbon dioxide, nitrogen
Components of Whole Blood
Plasma
(55% of whole blood)
Buffy coat:
leukocyctes and
platelets
(<1% of whole blood)
1 Withdraw blood
2 Centrifuge
and place in tube
• Hematocrit
• Males: 40-48%
• Females: 36- 42%
Erythrocytes
(45% of whole blood)
Formed
elements
Volume ratio of blood
cells and plasma called
hematocrit.
Normally it is men 0,400,48 l / l (40-48%) in
women - 0,36-0,42 l / l
(36-42%).
One liter of plasma has 65-85 gram of
proteins.
Concentration of
albumins is 35-50 g/L;
globulins is alpha-1-globulins – 1-4 g/L,
alpha-2-globulins – 4-8 g/L,
beta-globulins – 6-12 g/L,
gamma-globulins – 8-16 g/L;
fibrinogen – 2-4 g/L.
Plasma which are not contain fibrinogen
called serum (it is necessary for
understanding the immunology, therapy
etc.)
Albumin: 80% defines oncotic pressure transfer bilirubin,
urobilin , fatty acids , antibiotics , sulfonamides , are formed in
the liver , 17 g per day.
Globulin. In a fraction of α1- globulins are proteins associated
with carbohydrates. The fraction of α2- globulins include
protein ceruloplasmin, thyroxine binding protein , vitamin B12
-binding globulin , angiotensin . By β- globulins include
transfer of lipids, polysaccharides and iron.
Antibodies are mainly γ- globulins. Globulins are synthesized
in the liver , bone marrow , spleen and lymph nodes. By day 5
grams of globulin synthesized
Fibrinogen . (2-4 g / L) takes part in the formation of a blood
clot . Formed exclusively in the liver.
Maintaining a constant acid-base balance of
blood provided by buffer systems:
1. Bicarbonate buffer: consisting of carbonic acid
and bicarbonate (salt of carbonic acid). An
excess of alkali ions to maintain the acid-base
equilibrium reaction occurs.
Н2СО3 + ОН– ⇄ НСО3– + Н2О,
And with the accumulation of hydrogen ions
НСО3– + Н+ ⇄ Н2СО3
2. Phosphate buffer: is a mixture of single substituted phosphate
Н2РО4 –(weak acid) and dibasic phosphate НРО42–, which has
alkaline properties Н2РО4– / НРО42–
An excess of alkali ions to maintain the acid-base equilibrium
reaction occurs.
Н2РО4– + ОН– ⇄ НРО42– + Н2О,
And with the accumulation of hydrogen ions
НРО42– + Н+ ⇄ Н2О4–
3. The protein buffer: The protein buffer. It provides plasma
proteins, especially albumin. These amino acids have the ability
to ionization, ie possess amphoteric properties. An excess of
alkali ions to maintain the acid-base equilibrium reaction
occurs. And with the accumulation of hydrogen ions
RСООН + ОН– ⇄ RООС– + Н2О,
RСОО– + Н+ ⇄ RООН
4. Hemoglobin buffer. Essentially, there are two
hemoglobin buffers - one based on reduced
hemoglobin: NNb/Nb- and the other based on
oxyhemoglobin: NHbO2/HbO2. First prevails in
the venous blood, and the second - in the
arterial.
An excess of alkali ions maintain the acid-base
equilibrium reaction occurs:
НHb + ОН– ⇄ Нb– + Н2О;
НHbО2 + ОН– ⇄ НbО2– + Н2О,
When accumulation of hydrogen ions occurs:
Нb– + Н+ ⇄ ННb;
НbО2– + Н+ ⇄ ННbО2
1. pH (from Eng. power Hydrogen - the power of hydrogen),
which is equal to 7,35-7,45.
2. Tension of CO2 - pCO2, which is normally 5,3-6,1 kPa (4046 mm Hg).
3. Standard bicarbonate, international designation SB (standart
bikarbonate) - estimated. At standard conditions is 20-27 mg /
dL.
4. True, actual bicarbonate, international designation AB (actual
bikarbonate), is 190-25 mg / dL.
5. Excess (deficiency) framework, international designation CE
(D) (base ecxess (deficit) equals ± 2,3 mmol / l.
6. The sum of the bases of all the blood buffer systems,
international designation BB (batter bases) is 40-60 mg / dL.
The basic amount of iron in the
body (57.6%) is part of
hemoglobin in red blood cells
and is found.
Iron enters the body in the food
(meat, liver, fish, rice, peas,
raisins, apricots). It is best
absorbed iron, which is part of
the food in the form of heme.
Hemoglobin
Erythrocytes derive their colour from a
complex protein called hemoglobin. This
substance is composed of a pigment, heme,
containing iron, and the protein glohin.
Hemoglobin has the power to attract oxygen
molecules and to hold them in a loose chemical
combination known as oxyhemoglobin. It is
said, therefore, to have a chemical affinity for
oxygen.
Myoglobin
Hem is also part of the structure of myoglobin,
an oxygen-binding pigment found in red (slow)
muscles and in the respiratory enzyme
cytochrome. Porphyrins other than that found
in hem play a role in the pathogenesis of a
number of metabolic diseases (congenital and
acquired porphyria, etc.) It may be the reserve
pigments, which give the tissue oxygen in a
small oxygen condition.
To determine hemoglobin levels proposed many
different methods:
• Gas metric method - measuring the amount of
bound oxygen (1 g Hb can connect 1.36 ml of
oxygen);
• Iron metric - measuring iron levels in the blood
(iron content in Hb is 0.34%);
• Colorimetric - comparing the color of the
solution to the color of the blood of the
standard solution.