The BloodVNSG 1420 Anatomy & Physiology

Chapter 12

Blood Fundamental to maintaining homeostasisPumped by the heart through a closed system of blood vesselsClassified as a connective tissue cells make up nearly half of blood

Viscous (thick) fluidcolor depends based on oxygen content5 liters in average adult male8% of total body weight

Functions of BloodTransportation oxygen, carbon dioxide, nutrients, minerals,

vitamins, hormones & wastesRegulation of pH, fluid balance & body temperature

Protection against foreign organisms & blood loss

Transportation

GasesOxygen & carbon dioxide

Nutrients and other needed substancesNutrients, electrolytes (salts) & vitamins

WasteWater, acid, electrolytes, urea, pigments, hormones,

drugs, carbon dioxide

Hormones from their sites of origin to the organs they affect

RegulationpHBuffers in blood help to keep body fluid pH at

about 7.4

Fluid balanceRegulates amount of fluid in tissues by

maintaining proper osmotic pressure

HeatTransports heat generated in muscles to other

parts of the body, regulating body temperature

ProtectionDiseaseImportant defense against disease Carries cells & antibodies of the immune system

that protect against pathogens

Blood lossContains factors that protect against blood loss

from the site of an injury

Blood Constituents

Plasma - liquid portion of blood

Formed elements - cells & fragmentsErythrocytes - red blood cells - transport oxygenLeukocytes - white blood cells - protect against infectionPlatelets - thrombocytes - cell fragments that aid in

blood clotting

Blood Plasma55% of total blood volume91% water8% Proteins albumin, clotting factors, antibodies & complements

Remaining 1% =Nutrients - carbohydrates, lipids & amino acidsElectrolytes - mineralsWastes, hormones, vitamins & drugs, dissolved

gases

Plasma ProteinsAlbumin most abundant plasma protein, manufactured in

liver, important in maintaining blood osmotic pressure

Clotting factorsneeded for blood coagulation, produced in liver

Antibodiescombat infection

Complementsystem of enzymes needed to help fight pathogens

Plasma Nutrients

Glucose - Main carbohydrate in plasmaStored in liver and skeletal muscles as glycogen,

released for energyAbsorbed by capillaries of intestine after digestion

Amino acids - products of protein digestionAbsorbed by intestine capillaries also

Lipids – fats, cholesterol & lipoproteins

Formed ElementsErythrocytes - red blood cells (RBCs)transport oxygen

Leukocytes - white blood cells (WBCs)protect against infection

Platelets (thrombocytes)needed for clotting of blood

All formed elements (blood cells) form from hematopoietic stem cells in red bone marrow (ancestors of all blood cells)

See Table 10-2, p. 313

Erythrocytes (RBC)

ErythrocytesRed blood cells (RBCs) – biconcave (disk) shapedCarry oxygen bound to hemoglobinMost numerous of blood cells - 4.5 to 5 million per

cubic millimeter of bloodHemoglobin - protein that contains ironBlood color determined by oxygen content from lungs - bright red = oxygenated to lungs - darker red = deoxygenated

Mature red cells have no nucleus & cannot divide, must be replaced constantly

Erythrocytes (RBC)

More on Erythrocytes . . . Hemoglobin able to carry hydrogen ions (acidic)Acts as buffer to keep pH of 7.4 (acid-base

balance)Transport carbon dioxide from tissues to lungs for elimination Carbon monoxide blocks ability of hemoglobin to carry

oxygen

Erythropotein - hormone from kidneystimulates production of red blood cells in response

to decreased oxygen supply

LeukocytesWhite blood cells (WBCs) 5,000 to 10,000 per cubic millimeter of blood

(round shape)ColorlessContain prominent nuclei

Different types identified by size, shape of nucleus & appearance or lack of granules in cytoplasm when stained (Wright’s stain)% of each cell type useful in diagnosis

Granulocytes/ Agranulocytes

GRANULOCYTESNeutrophil

Polymorphs, polys, segs

EosinophilBasophil

AGRANULOCYTESLymphocytesMonocyte

Granular Leukocytes / GranulocytesGranules visible when stainedNeutrophils - most numerous of WBCs

Active in fighting infectionsEosinophils

increase during allergic reactions & parasite infestation

Basophilsincrease during allergic reactions & inflammatory

reactions

More on Neutrophils

Various shaped nucleiPolymorps or polysSegmented nucleus - segsPolymorphonuclear neutrophils -PMN

Immature nuclei - thick curved bands Increase in band cells (stab or staff cells) is sign of

infection & active neutrophil production

Agranular Leukocytes / AgranulocytesLack easily visible granules

LymphocytesActive in immunitySecond most numerous of WBCs

MonocytesLargest in sizeFunction as phagocytes

Function of LeukocytesDestruction of pathogensRid body of foreign materials - cell debris &

pathogensEngage in phagocytosis

Engulfing of pathogens [Neutrophils & monocytes leave blood vessels when pathogens enter tissues]

Travel by ameboid motion to areaPus = mixture of live & dead bacteria & live &

dead leukocytesAbscess = pus localized in an area

More on Leukocyte Function . . . Monocytes enter tissues, enlarge & mature into macrophagesMacrophages

active in disposal of pathogens or foreign material

Some lymphocytes become plasma cellsPlasma cells

lymphocytes active in producing circulating antibodies needed for immunity

Platelets / ThrombocytesSmallest of formed elements - cell fragments from megakarocytes (large bone marrow cells), not cellsNo nuclei or DNA

150,000 to 450,000 per cubic millimeterEssential in blood coagulation (clotting)In blood vessel injuryplatelets stick together to form plug that seals

woundplatelets then release chemicals to form clot to stop

blood loss

Platelets

Activated Platelets

Hemostasis

Process that prevents blood loss from blood vessel rupture or injuryHemostasis events1. Contraction of blood vessels

Vasoconstriction reducies diameter of vessel reducing blood flow

2. Formation of platelet plug3. Formation of blood clot

Hemostasis

Blood Clotting / Coagulation

Balance of regulating inactive compounds in blood stream:Procoagulants - promote blood clotting

Activate with injury to form clotAnticoagulants - prevent blood clotting

Prevail in normal conditions

12 clotting factors involved in clotting process

Clotting FactorsFactors I - XII - blood clotting factorsFinal steps in clotting = conversion of fibrinogen to fibrin Substance from damaged tissue form prothrombinase –

which converts prothrombin to thrombinThrombin converts fibrinogen(plasma protein) to solid

threads of fibrinNetwork of fibrin threads form clot

Serum - fluid that remains after blood clotsPLASMA = SERUM + CLOTTING FACTORS

Blood TypesBlood transfusions transfer of blood from 1 person to another - given

for hemorrhage (excessive bleeding) or disease - hemorrhage results in oxygen & nutrients to cells

Incompatible transfusions cause destruction of donor red cells (hemolysis) &

transfusion reactions

Antigens – proteins on surface of RBCs that react with antibodies – to cause incompatibility

ABO Blood Type Group

Blood type describes type of antigen present on red blood cellsType A has A antigen onlyType B has B antigen onlyType AB has A & B antigensType O has no antigen

Testing For Blood TypeTested by mixing blood sample with anti-sera to different antigensBlood sera containing antibodies to A or B antigen

preparedSera applied to blood sampleAgglutination occurs – clumping together of red cells

when mixed with matching anti-serum[Type A reacts with Anti-A only; Type B reacts with Anti-B only; Type AB reacts with both;

Type O reacts with NEITHER]

See Table 10-3 page 319 & Figure 10-8, page 321

ABO Blood Type Group

Blood Compatibility

Blood type determined by heredityIn an emergency, Type O blood can be given to any ABO typeType O is universal donor

Blood Type AB can receive from any ABO typeSafest to give blood of same type in normal conditions

THE Rh Factor

Antigens – proteins on the surface of red cellsAntibody – substance produced in response to a

specific antigen

Rh factor / D antigen – red cell antigen groupRh positive (+) blood has Rh antigenRh negative(-) blood has no Rh antigen

Rh positive blood given to Rh negative person will produce antibody to Rh antigens

Rh IncompatibilityPotential problem in pregnancy

Rh (-) mother can develop antibodies to RH protein of Rh (+) fetusRBCs can enter mother’s circulation during

pregnancy & childbirth & cause immune response

In subsequent pregnancy with Rh (+) fetus, anti-Rh antibodies from mother can pass to fetus causing fetal RBC destruction

Hemolytic Disease of Newborn (HDN)Rhogam Rh (D) immune globulin (antibody) is given to Rh

(-) mother during pregnancy & after delivery to clear antigens from her circulation & prevent immune system response

Destruction of RBCs of Rh (+) fetus by anti-Rh antibodies of sensitized Rh (-) motherInfant with Hemolytic Disease of Newborn (HDN) can receive lifesaving RH negative replacement blood transfusion

Use of Blood & Blood ComponentsBlood can be stored up to 35 days by blood bankAnti clotting solution, Expiration date

Important to keep extra Type O (universal donor)

Whole blood transfusions - used only to replace large volume blood losses

Massive hemorrhage from serious mechanical injury Internal bleeding, as with bleeding ulcersDuring or after surgeryBlood replacement for Hemolytic Disease of Newborn

More Types of Transfusions . . .

Autologous – donated for a person’s own useElective surgery

Blood component transfusions – formed elements are separated by centrifugationPlasma components & expandersHemapheresis – desired elements kept,

remainder returned to donorPlasmapheresis – plasma kept, formed

elements returned to donor

Blood Components Plasma/FFP

Use of PlasmaReplace blood volumePrevent or treat circulatory failure (shock)Because no RBCs, no incompatibility problemsFurther separationProtein fractions (to treat plasma protein deficiency)Serum albumin Immune serumClotting factors (cryoprecipitate obtained by freezing, contains

clotting factors)- replacement useGamma globulin (contain antibodies - used for replacement)

Blood Studies

Standard part of routine physical examsHematocrit & Hemoglobin Blood cell studiesBlood slide (smear)Blood chemistry testsCoagulation studies

Many tests done by machines

HematocritMeasures volume percentage of packed red blood cells in whole blood# of mls of RBCs per 100mls of whole blood

Blood is spun in centrifuge to separate cellular elements from plasmaNormal hematocrit (Hct) rangesAdult males - 42-54Adult female - 36-46

Below normal levels of RBCs signify anemiaSee Figure 10-1, p. 311

Hemoglobin Tests

Measures grams of hemoglobin per 100 mls of whole bloodHemoglobin needed for oxygen delivery to tissuesColor of blood is compared to a color scale to measure hemoglobin released from red cellsNormal hemoglobin (Hgb) rangesAdult males - 14-17 gramsAdult females - 12-15 grams

Below normal levels of hemoglobin signify anemia

More on Hemoglobin Tests . . .

Electropheresis Process that measures normal & abnormal types of

hemoglobinElectric current is passed through liquid that

contains hemoglobinUseful in diagnosis sickle cell anemia

Blood Cell Counts

RBC & WBCAutomated methods or visual counts under a microscope

Platelets counts (automated)

Normal countsRBC = 4.5 to 5.5 million/cubic millimeter (mm)WBC = 5000 to10,000/cubic mmPlatelets = 150,000 to 450,000/cubic mm

Blood Cell Count Changes

Increased RBC count is polycythemiaDecreased RBC count is anemia

Increased WBC count is leukocytosisDecreased WBC count is leukopenia

Blood Smear SlideComplete blood count (CBC) Includes Hgb & Hct (H&H), blood cell counts &

stained blood slide for differential cell countsBlood smear - blood drop spread thinly & evenly over glass slide & stained with Wright’s stain Red cells & platelets studied for abnormalities Also look for parasites

% of different WBCs – differential white cell count ( add up to 100%)

Blood Chemistry Tests

Tests on blood serum typically by machineElectrolytes - sodium, potassium, chloride & bicarbonateBlood glucose – glucose/sugar in bloodBlood urea nitrogen (BUN) & creatinine - nitrogen waste productsEnzymes - CK, LDH, & others - can indicate tissue damage; an excess of Alkaline Phosphatase can indicate liver disorder or cancer

More on Blood Chemistry Tests . . .

Lipids - cholesterol, triglycerides & lipoproteins

Plasma proteins - albumin & globulin

Glucose tolerance tests - after glucose is administered - increased glucose indicates faulty cell metabolism

Hormones, vitamins, antibody valuesDrug levels - therapeutic or toxic

Coagulation Studies

Aid in treating blood clotting disordersBefore surgery, & during disease treatment (such as hemophilia)

Clotting factor assaysBleeding timeClotting timeCapillary strength Platelet function

Bone Marrow Biopsy

Red marrow sample obtained from sternum, sacrum or iliac crestUsed in diagnosing blood marrow disordersLeukemiaSome types of anemia

Helpful Website on Blood

http:www.wadsworth.org/chemheme/heme/microscope/cellist.htm