The Physiology of Blood

transcript

NOMAD:2005: BP: INTROVERVIENOMAD:2005: BP: INTROVERVIEWW

THE PHYSIOLOGY THE PHYSIOLOGY OFOF BLOODBLOOD

AN INTRODUCTION AND AN INTRODUCTION AND OVERVIEWOVERVIEW

ByByDr.M.ANTHONY DAVID, MD.Dr.M.ANTHONY DAVID, MD.

WHAT IS WHAT IS BLOODBLOOD?? IT IS A IT IS A LIQUID CONNECTIVE LIQUID CONNECTIVE

TISSUETISSUE IN AN AVERAGE 70 Kg MAN:IN AN AVERAGE 70 Kg MAN:

100 Trillion cells.100 Trillion cells. Of which 25 trillions are Of which 25 trillions are RedRed Blood Blood

Cells!Cells! The average blood volume is 5 – 6 The average blood volume is 5 – 6

lts.lts. It is roughly It is roughly 7%7% of the total body of the total body

weight.weight.

HEMATOLOGY: THE STUDY OF BLOODMADE POSSIBLE BY MICROSCOPY

THE COMPOSITION OF BLOOD THE COMPOSITION OF BLOOD PLASMAPLASMA

The Liquid: Plasma:The Liquid: Plasma: Water, the solventWater, the solvent The solute:The solute:

Proteins:Proteins: AlbuminAlbumin Globulins:#Globulins:# FibrinogenFibrinogen

Electrolytes:Electrolytes: Na+Na+ K+K+ Ca++Ca++

Organic moleculesOrganic molecules UreaUrea GlucoseGlucose LipidsLipids

BLOOD PLASMA

WATER SOLUTES

PROTEINS

ELECTRO-LYTES

ORGANIC MOLECULES

THE FORMED ELEMENT: THE FORMED ELEMENT: CELLSCELLS

BLOOD CELLS

ERYTHROCYTES LEUCOCYTES THROMBOCYTES

BLOOD: COMPOSITIONBLOOD: COMPOSITION

FUNCTIONS OF BLOODFUNCTIONS OF BLOOD NUTRITIVE RESPIRATORY EXCRETORY BODY DEFENCE: IMMUNITY TRANSPORT:

HORMONES VITAMINS DRUGS

BLOOD:TRANSPORTING BLOOD:TRANSPORTING HORMONE MOLECULESHORMONE MOLECULES

OXYGEN & COOXYGEN & CO22 TRANSPORTTRANSPORT

FUNCTIONS OF BLOODFUNCTIONS OF BLOOD HOMEOSTATIC FUNCTION:HOMEOSTATIC FUNCTION:

ACID BASE BALANCE.ACID BASE BALANCE. ELECTROLYTE BALANCE.ELECTROLYTE BALANCE. HEMOSTASIS.HEMOSTASIS. THERMOREGULATION.THERMOREGULATION.

WHAT IS BLOOD VOLUME?WHAT IS BLOOD VOLUME? The total amount of blood in The total amount of blood in

circulation plus the amount of circulation plus the amount of blood in the reservoirs blood in the reservoirs constitutes the “Blood Volume”constitutes the “Blood Volume”

The average adult 70 kg man The average adult 70 kg man has a blood volume of 5 to 6 has a blood volume of 5 to 6 litres.litres.

EXPRESSION OF BLOOD EXPRESSION OF BLOOD VOLUMEVOLUME

Usually Blood Volume is Usually Blood Volume is expressed in expressed in litersliters..

It can also be expressed in It can also be expressed in relation to body weightrelation to body weight.. It is 7% Body WeightIt is 7% Body Weight

Another way to express it is in Another way to express it is in terms of terms of Body Surface AreaBody Surface Area.. Whole Blood : 2.8 Lts/MWhole Blood : 2.8 Lts/M22

Plasma : 1.5 Lts/MPlasma : 1.5 Lts/M2 2

IN HUMANS: ONLY INDIRECT IN HUMANS: ONLY INDIRECT METHODSMETHODS

DYE DILUTION TECHNIUE:DYE DILUTION TECHNIUE: PRINCIPLE:PRINCIPLE:

Injection of a known volume of non Injection of a known volume of non toxic substance into the circulation.toxic substance into the circulation.

Measuring the dilution of this Measuring the dilution of this injected dye after some time. injected dye after some time.

This gives us the Plasma volume.This gives us the Plasma volume.

METHODS OF MEASURING METHODS OF MEASURING BLOOD VOLUMEBLOOD VOLUME

DYE DILUTION TECHNIQUEDYE DILUTION TECHNIQUE

V1 = VOLUMEC1 = CONCENTRATION OF DYE V2 = VOLUME

C2 = CONC. OF DYEV1 X C1 = V2 X C2ORV2 = V1 X C1 = Amount of Dye injected C2 Conc. Of the dye in the Plasma

HEMATOCRIT (PCV)HEMATOCRIT (PCV) The volume of erythrocytes in The volume of erythrocytes in

the whole blood expressed in the whole blood expressed in percentage is the percentage is the HematocritHematocrit..

This is also called as Packed This is also called as Packed Cell Volume or Cell Volume or PCVPCV..

This is determined by the This is determined by the WintrobeWintrobe’s tube, using a ’s tube, using a Centrifuge. Centrifuge.

HEMATOCRITHEMATOCRIT A mixture of blood and double A mixture of blood and double

oxalate (K – NHoxalate (K – NH44) is taken upto 100 ) is taken upto 100 mark in the Wintrobe’s tube.mark in the Wintrobe’s tube.

The tube is placed in the centrifuge.The tube is placed in the centrifuge. It is rotated at 3,000 rpm for 30 It is rotated at 3,000 rpm for 30

minutes.minutes. The Hematocrit is then read off the The Hematocrit is then read off the

tube.tube. Blood Volume = Blood Volume = Plasma Volume X Plasma Volume X 100100

100 - PCV100 - PCV

HEMATOCRITHEMATOCRIT

BLOOD VOLUME: BLOOD VOLUME: PHYSIOLOGICAL VARIATIONSPHYSIOLOGICAL VARIATIONS

AGEAGE SEXSEX TEMPERATURETEMPERATURE BODY WEIGHTBODY WEIGHT BODY SURFACE BODY SURFACE

AREAAREA

PREGNANCYPREGNANCY EXERCISEEXERCISE POSTUREPOSTURE HYPOXIAHYPOXIA EMOTIONSEMOTIONS

BLOOD VOLUME & AGEBLOOD VOLUME & AGEAGEAGE BLOOD VOLUME in BLOOD VOLUME in

LitersLitersAT BIRTHAT BIRTH 0.30.36 Months 6 Months 0.50.5

1 year1 year 0.70.72yrs 6 2yrs 6

monthsmonths1.01.0

4 years4 years 1.31.37 years7 years 1.71.710 years10 years 2.5(Girls); 3.2 (Boys)2.5(Girls); 3.2 (Boys)ADULTSADULTS 5 (Men) 4.5 (Women)5 (Men) 4.5 (Women)

1. SEX:1. SEX: Males have more Males have more

blood volume blood volume than females.than females.

2. TEMPERATURE:2. TEMPERATURE: Acute exposure Acute exposure

to cold causes to cold causes reduction in reduction in blood volume due blood volume due to Plasma water to Plasma water loss to tissues.loss to tissues.

3. BODY WEIGHT: It is usually 7% of the Body

Weight.4. BODY SURFACE AREA:

2.8 Lts/Square Meters of BSA

5. PREGNANCY:5. PREGNANCY: Increases by 20 – 30% Increases by 20 – 30%

due to mass of fetus.due to mass of fetus.6. EXERCISE:6. EXERCISE:

Vigorous exercise Vigorous exercise causes an increase.causes an increase.

7. POSTURE:7. POSTURE: Changing from lying Changing from lying

down to erect.down to erect.

8. HYPOXIA:8. HYPOXIA: Seen in High Seen in High

altitudes.altitudes. ErythrocytesErythrocytes So So Blood volume. Blood volume.

9. EMOTIONS:9. EMOTIONS: Excitement causes Excitement causes

an increase in the an increase in the Blood volume.Blood volume.

BLOOD VOLUME: BLOOD VOLUME: PATHOLOGICALPATHOLOGICAL VARIATIONS VARIATIONS

DECREASE IN BLOOD VOLUME IS DECREASE IN BLOOD VOLUME IS HYPOVOLEMIA. CAUSES:HYPOVOLEMIA. CAUSES:

1. BLOOD LOSS:1. BLOOD LOSS: 2. SHOCK:2. SHOCK:

Crushing InjuryCrushing Injury CardiogenicCardiogenic NeurogenicNeurogenic Psychogenic.Psychogenic.

3. HEMOLYSIS: Mismatched

transfusion Snake bite Black water

fever Hemorrhagic

Plagues/Dengue Measles

HYPOVOLEMIA: CAUSES HYPOVOLEMIA: CAUSES (contd)(contd)

4. DEHYDRATION:4. DEHYDRATION: DiarrhoeaDiarrhoea CholeraCholera GastroenteritisGastroenteritis BurnsBurns Hyperemesis.Hyperemesis.

HYPOVOLEMIA: CAUSES (contd)

5. ANEMIA:5. ANEMIA: Decreased RBC volumeDecreased RBC volume Plasma may increase.Plasma may increase.

6. OBESITY:6. OBESITY: Blood volume per body weight decreases Blood volume per body weight decreases

though Blood volume per BSA may be though Blood volume per BSA may be normal.normal.

7. HYPOTHYROIDISM (MYXEDEMA):7. HYPOTHYROIDISM (MYXEDEMA): Decrease in Blood volume.Decrease in Blood volume.

8. ACUTE COLD: Decreases blood volume.8. ACUTE COLD: Decreases blood volume.

HYPOVOLEMIA: CAUSES (contd)HYPOVOLEMIA: CAUSES (contd)

TREATMENT FOR BLOOD TREATMENT FOR BLOOD LOSSLOSS

TRANSFUSION OF WHOLE TRANSFUSION OF WHOLE BLOOD OF THE SAME BLOOD OF THE SAME BLOOD GROUP & TYPE.BLOOD GROUP & TYPE.

INFUSION OF PLASMAINFUSION OF PLASMA INFUSION OF DEXTRAN OR INFUSION OF DEXTRAN OR

NORMAL SALINE.NORMAL SALINE.

HEMOPOIESIS & HEMOPOIESIS & ERYTHROPOIESISERYTHROPOIESIS

ByByDr. M.Anthony David.MD.Dr. M.Anthony David.MD.

HEMOPOIESIS: INTROHEMOPOIESIS: INTRO Hemo: Referring to blood cells Poiesis: “The development or

production of” The word Hemopoiesis refers to the

production & development of all the blood cells: Erythrocytes: Erythropoiesis Leucocytes: Leucopoiesis Thrombocytes: Thrombopoiesis.

Begins in the 20th week of life in the fetus & continues in the red bone marrow till death.

STEM CELL THEORYSTEM CELL THEORY All blood cells are produced by the All blood cells are produced by the

bone marrowbone marrow.. They come from a single class of They come from a single class of

primitive mother cells called as: primitive mother cells called as: PLURIPOTENT STEM CELLSPLURIPOTENT STEM CELLS.. These cells give rise to blood cells of:These cells give rise to blood cells of:

Myeloid Myeloid series: Cells arising mainly from series: Cells arising mainly from the bone marrow.the bone marrow.

LymphoidLymphoid series: cells arising from series: cells arising from lymphoid tissues. lymphoid tissues.

PROGENITOR CELLSPROGENITOR CELLS Committed stem cells lose their Committed stem cells lose their

capacity for self-renewal.capacity for self-renewal. They become irreversibly committed.They become irreversibly committed. These cells are termed as “These cells are termed as “Progenitor Progenitor

cellscells”” They are regulated by certain They are regulated by certain

hormones or substances so that they hormones or substances so that they can:can: ProliferateProliferate Undergo Maturation.Undergo Maturation.

BLOOD CELLS: DEVELOPMENTBLOOD CELLS: DEVELOPMENT

PROGENITOR CELLS

LYMPHOID CELLS

PRONORMOBLAST

MEGAKARYOBLASTMYELOBLASTMONOBLAST

LYMPHOCYTESERYTHROCYTESTHROMBOCYTESGRANULOCYTESMONOCYTES

ERYTHROPOIESIS: ERYTHROPOIESIS: SITES/PHASESSITES/PHASES

INTRAUTERINEINTRAUTERINE LIFE:LIFE: INTRAVASCULAR PHASEINTRAVASCULAR PHASE:: Upto 3 Upto 3rdrd

month of Intra Uterine Life.month of Intra Uterine Life. Endothelial cells = = = RBCsEndothelial cells = = = RBCs

HEPATIC PHASEHEPATIC PHASE: 3: 3rdrd to 5 to 5th th month IUL month IUL Liver & SpleenLiver & Spleen nRBCs from Mesenchymal cells.nRBCs from Mesenchymal cells.

MYELOID PHASEMYELOID PHASE: From 5: From 5thth month of month of IUL onwards.IUL onwards.

POST NATAL LIFE:POST NATAL LIFE: CHILDREN:CHILDREN:

Predominantly Red Bone Marrow of Predominantly Red Bone Marrow of skeleton:skeleton:

Axial & Axial & Appendicular.Appendicular.

ADULTS:ADULTS: Red Bone Marrow of Axial Skeleton.Red Bone Marrow of Axial Skeleton.

ERYTHROPOIESIS: SITES/PHASESERYTHROPOIESIS: SITES/PHASEScontd.contd.

PROERYTHROBLAST

BASOPHILICERYTHROBLAST

POLYCHROMATOPHILIC ERYTHROBLAST

ORTHOCHROMATIC ERYTHROBLAST

RETICULOCYTE

MATURE ERYTHROCYTES

ERYTHROPOIESISERYTHROPOIESIS

FACTORS REGULATINGFACTORS REGULATINGERYTHROPOIESISERYTHROPOIESIS

SINGLE MOST IMPORTANT SINGLE MOST IMPORTANT REGULATOR: REGULATOR: “TISSUE OXYGENATION”“TISSUE OXYGENATION”

BURST PROMOTING ACTIVITYBURST PROMOTING ACTIVITY ERYTHROPOIETINERYTHROPOIETIN IRONIRON VITAMINS:VITAMINS:

Vitamin BVitamin B1212 Folic AcidFolic Acid

MISCELLANEOUSMISCELLANEOUS

ERYTHROPOIETINERYTHROPOIETIN A hormone produced by the Kidney.A hormone produced by the Kidney. Nowadays available as Synthetic Nowadays available as Synthetic

EpoietiEpoieti Increases the number of:Increases the number of:

Nucleated precursors in the marrow.Nucleated precursors in the marrow. Reticulocytes & Mature Erythrocytes in Reticulocytes & Mature Erythrocytes in

the blood.the blood.

VITAMINSVITAMINS BB1212: Cyanocobalamine & Folic Acid:: Cyanocobalamine & Folic Acid:

Is also called Is also called Extrinsic Factor of CastleExtrinsic Factor of Castle.. Needs the Needs the Intrinsic FactorIntrinsic Factor from the from the

Gastric juice for absorption from Small Gastric juice for absorption from Small Intestine.Intestine.

Deficiency causes Deficiency causes Pernicious Pernicious (When IF (When IF is missing) or Megaloblastic Anemia.is missing) or Megaloblastic Anemia.

Stimulates ErythropoiesisStimulates Erythropoiesis Is found in meat & diary products.Is found in meat & diary products.

IRONIRON Essential for the synthesis of Essential for the synthesis of

HemoglobinHemoglobin.. Deficiency causes Deficiency causes Microcytic, Microcytic,

Hypochromic Anemia.Hypochromic Anemia. Deficiency causes the Deficiency causes the

commonest type of Anemia.commonest type of Anemia.

The Physiology of Blood

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