The Cardiovascular System: Blood

The Cardiovascular System:The Cardiovascular System:

BloodBlood

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Blood Blood

Primary Functions Primary Functions – Brings oxygen and nutrients to the Brings oxygen and nutrients to the cells. cells.

– Carries away waste. Carries away waste. – Distributes heatDistributes heat– Helps defend the body against infectionHelps defend the body against infection

Related Combining FormsRelated Combining Forms– hem/o, hemat/ohem/o, hemat/o

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CharacteristicsCharacteristics

There are 4-6 L of blood in the human body There are 4-6 L of blood in the human body (depending on body size)(depending on body size)

About 55% of the blood is a straw-coloured fluid About 55% of the blood is a straw-coloured fluid called plasmacalled plasma

The remaining portion of blood is made up of the The remaining portion of blood is made up of the “formed elements”:“formed elements”:– ErythrocytesErythrocytes– LeukocytesLeukocytes– ThrombocytesThrombocytes

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PlasmaPlasma

Plasma is about 91% waterPlasma is about 91% water– The rest consists of proteins, The rest consists of proteins,

nutrients, hormones, and waste nutrients, hormones, and waste productsproducts

Proteins include albumin, Proteins include albumin, globulins, fibrinogen, and prothrombinglobulins, fibrinogen, and prothrombin

When the two major clotting When the two major clotting proteins (fibrinogen and prothrombin) are removed, proteins (fibrinogen and prothrombin) are removed, the fluid is called the fluid is called serumserum

– Blood gases are dissolved in plasma (ex Oxygen, Blood gases are dissolved in plasma (ex Oxygen, Carbon Dioxide, Nitrogen)Carbon Dioxide, Nitrogen)

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Formed ElementsFormed Elements

Erythrocytes (Red Blood Cells)Erythrocytes (Red Blood Cells)– Erythr/oErythr/o means red, means red, -cyte-cyte means cell means cell– Carry oxygen to the body tissuesCarry oxygen to the body tissues– 99% of the cells in blood99% of the cells in blood– Biconcave (increases surface area to intracellular Biconcave (increases surface area to intracellular

space ratio)space ratio)– Membrane is very flexibleMembrane is very flexible– Do not have nucleiDo not have nuclei

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Erythrocytes carry a Erythrocytes carry a protein called protein called Hemoglobin (Hb)Hemoglobin (Hb)– Hemoglobin molecules Hemoglobin molecules

contain atoms of iron contain atoms of iron which attract oxygen which attract oxygen when it is plentiful and when it is plentiful and release it when scarcerelease it when scarce

– Iron gives hemoglobin it’s Iron gives hemoglobin it’s red colourred colour

Protein is also Protein is also essential for Hb essential for Hb synthesis synthesis

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Life spanLife span– RBC’s live for approximately 120 daysRBC’s live for approximately 120 days– At that time they become fragile, and are removed At that time they become fragile, and are removed

from the bloodstream by macrophages located in the from the bloodstream by macrophages located in the liver, spleen, and bone marrowliver, spleen, and bone marrow

– When the old cells are destroyed, the iron they When the old cells are destroyed, the iron they contained is released and is carried back to the bone contained is released and is carried back to the bone marrow to be used in the synthesis of new marrow to be used in the synthesis of new hemoglobin (excess is stored in the liver)hemoglobin (excess is stored in the liver)

– The heme part of the Hb molecule cannot be recycled The heme part of the Hb molecule cannot be recycled and is converted to the waste product bilirubin by the and is converted to the waste product bilirubin by the macrophagesmacrophages

The bilirubin is removed from the blood by the The bilirubin is removed from the blood by the liver, and is excreted into bileliver, and is excreted into bile

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Leukocytes (White Blood Cells)Leukocytes (White Blood Cells)– Leuk/oLeuk/o means white, means white, -cyte-cyte means cell means cell– Protect the body against invadersProtect the body against invaders– Have a nucleusHave a nucleus– Can change shape and move out through the Can change shape and move out through the

vessel walls into the tissuesvessel walls into the tissues– There are 5 kinds of WBC’s:There are 5 kinds of WBC’s:

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NeutrophilsNeutrophils– Formed in red bone Formed in red bone

marrowmarrow– Most common typeMost common type– Can leave the Can leave the

bloodstream to find, bloodstream to find, engulf, and swallow engulf, and swallow germs germs

phagocytosis phagocytosis ((phag/ophag/o means to means to eat)eat)

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BasophilsBasophils– Assist in the Assist in the

inflammatory responseinflammatory response– Responsible for many Responsible for many

of the symptoms of of the symptoms of allergiesallergies

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EosinophilsEosinophils– Destroy parasitic Destroy parasitic

organismsorganisms– Play a role in allergic Play a role in allergic

reactionsreactions

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MonocytesMonocytes– Formed in red bone Formed in red bone

marrow, lymph nodes, marrow, lymph nodes, and spleenand spleen

– Perform phagocytosisPerform phagocytosis- clean up bacteria, dead - clean up bacteria, dead and dying cells, and other and dying cells, and other debrisdebris

– Can differentiate into Can differentiate into macrophagesmacrophages

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LymphocytesLymphocytes– Formed in the red Formed in the red

bone marrow, lymph bone marrow, lymph nodes, and spleennodes, and spleen

– Participate in the Participate in the immune response – immune response – recognizing foreign recognizing foreign antigens and creating antigens and creating antibodiesantibodies

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ThrombocytesThrombocytes– AKA PlateletsAKA Platelets

Thromb/oThromb/o means means clotclot

– Not actual cells, but Not actual cells, but are cell fragmentsare cell fragments

– Help to prevent blood Help to prevent blood loss (loss (hemostasishemostasis – – watch spelling!) and watch spelling!) and form clotsform clots

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Formed in the bone marrow by the stem Formed in the bone marrow by the stem cells in a process called cells in a process called hematopoiesishematopoiesis – (-poiesis(-poiesis means production, formation) means production, formation)– All formed elements are derived from the All formed elements are derived from the

same hematopoietic stem cellssame hematopoietic stem cellsProteins in the bone marrow and blood influence Proteins in the bone marrow and blood influence the stem cells to change size and shape to the stem cells to change size and shape to become specializedbecome specialized

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Blood TypesBlood Types

Many different factors that identify blood Many different factors that identify blood “types”“types”– 2 Major:2 Major:

ABO blood groupABO blood group

Rh factorRh factor

– Both are inheritedBoth are inherited

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ABO GroupABO Group– Four major groups identified by the presence Four major groups identified by the presence

of antigens on the surface of the cellof antigens on the surface of the cellType A – has A antigen, B antibodyType A – has A antigen, B antibodyType B – has B antigen, A antibodyType B – has B antigen, A antibodyType AB – has both A and B antigen, no Type AB – has both A and B antigen, no antibodiesantibodiesType O – has no antigens, both A and B antibodiesType O – has no antigens, both A and B antibodies

– The genes for the antigens are inherited in a The genes for the antigens are inherited in a co-dominant patternco-dominant pattern

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– Each type also natural antibodies circulating in the Each type also natural antibodies circulating in the blood against the antigens blood against the antigens notnot present on the cell present on the cell surfacesurface

– These antibodies bind to antigens of a foreign type These antibodies bind to antigens of a foreign type and cause the cells to clump (agglutinate) and rupture and cause the cells to clump (agglutinate) and rupture (hemolysis)(hemolysis)

– Therefore, donated blood must be very carefully Therefore, donated blood must be very carefully cross-matched cross-matched

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If a person has:If a person has: They can receive blood of type:They can receive blood of type:

Type AType A Type A, Type OType A, Type O

Type BType B Type B, Type OType B, Type O

Type ABType AB Type AB,Type A, Type B, Type OType AB,Type A, Type B, Type O

Type OType O Type OType O

http://nobelprize.org/medicine/educational/landsteiner/index.html

http://www.biology.arizona.edu/human_bio/problem_sets/blood_types/rh_factor.html

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Rh FactorRh Factor– If the Rh factor antigen is present on the If the Rh factor antigen is present on the

RBCs, the blood is said to be Rh positiveRBCs, the blood is said to be Rh positive– If the Rh factor antigen is not present on the If the Rh factor antigen is not present on the

RBCs, the blood is said to be Rh negativeRBCs, the blood is said to be Rh negativePeople who are Rh negative do not have natural People who are Rh negative do not have natural antibodies to the Rh antigen, but the antibodies antibodies to the Rh antigen, but the antibodies can develop if exposed to positive bloodcan develop if exposed to positive blood

– Rh positive is the dominant allele (85% of Rh positive is the dominant allele (85% of Americans are Rh positive)Americans are Rh positive)

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CoagulationCoagulation

AKA Blood ClottingAKA Blood Clotting

When injury occurs, platelets clump at the When injury occurs, platelets clump at the site to create a site to create a platelet plugplatelet plug

A cascade of events then occurs which A cascade of events then occurs which results in prothrombin and fibrinogen results in prothrombin and fibrinogen working together to form fibers of working together to form fibers of fibrinfibrin which cover the site, and pull the sides of which cover the site, and pull the sides of the cut together for healingthe cut together for healing

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Blood PathologyBlood Pathology

Leukemia Leukemia (-emia(-emia means blood condition) means blood condition)– Malignancy of the blood forming tissuesMalignancy of the blood forming tissues

Overproduction of immature white blood cellsOverproduction of immature white blood cells– Very susceptible to infectionVery susceptible to infection

Deficiency of other formed elementsDeficiency of other formed elements– Anemia, hemorrhageAnemia, hemorrhage

May be treated with chemotherapy and bone May be treated with chemotherapy and bone marrow transplantsmarrow transplants

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LeukemiaLeukemia

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AnemiaAnemia– Deficiency of erythrocytes (erythropenia), or Deficiency of erythrocytes (erythropenia), or

insufficient hemoglobininsufficient hemoglobin– Often just a sign of another diseaseOften just a sign of another disease– Symptoms can include:Symptoms can include:

PallorPallorTachycardiaTachycardiaChest painChest painShortness of breathShortness of breathFatigueFatigue

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Aplastic AnemiaAplastic Anemia– Absence of all formed elements of bloodAbsence of all formed elements of blood– Failure of hematopoiesisFailure of hematopoiesis

Plast/oPlast/o means growth or formation means growth or formation

– Can be idiopathic, or due to chemical Can be idiopathic, or due to chemical exposure, pregnancy, lupus, etcexposure, pregnancy, lupus, etc

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Hemolytic AnemiaHemolytic Anemia– Erythrocytes are destroyed faster than they Erythrocytes are destroyed faster than they

can be replacedcan be replaced– Can be caused by infection, medication, Can be caused by infection, medication,

inheritance, or autoimmune disordersinheritance, or autoimmune disorders-lytic-lytic means to destroy means to destroy

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Iron-deficiency AnemiaIron-deficiency Anemia– Decrease in the number of erythrocytes Decrease in the number of erythrocytes

because there is not enough ironbecause there is not enough ironDue to inadequate intake, malabsorption, Due to inadequate intake, malabsorption, pregnancy and lactation, chronic blood losspregnancy and lactation, chronic blood loss

Occurs in approx. 20% of women, 50% of pregnant Occurs in approx. 20% of women, 50% of pregnant women, and 3% of menwomen, and 3% of men

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Megaloblastic AnemiaMegaloblastic Anemia– Erythrocytes are unusually Erythrocytes are unusually

largelarge– Usually due to a deficiency of Usually due to a deficiency of

folic acid or vitamin B12folic acid or vitamin B12

Pernicious AnemiaPernicious Anemia– Autoimmune disorderAutoimmune disorder– Cells are unusually formed Cells are unusually formed

due to an inability of the body due to an inability of the body to absorb vitamin B12to absorb vitamin B12

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Sickle Cell AnemiaSickle Cell Anemia– Inherited disorder that causes abnormal Inherited disorder that causes abnormal

hemoglobin formationhemoglobin formationCells become crescent shapedCells become crescent shaped

Very fragile – can break apart easilyVery fragile – can break apart easily

Function abnormally and cause clots to formFunction abnormally and cause clots to form

Results in painful “crises”Results in painful “crises”– Inherited as a recessive (people who inherit Inherited as a recessive (people who inherit

one dominant and one recessive allele have one dominant and one recessive allele have sickle cell trait)sickle cell trait)

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ThalassemiaThalassemia– Inherited condition that results in absent or Inherited condition that results in absent or

decreased production of normal hemoglobindecreased production of normal hemoglobin– Many different forms, can be mild or severeMany different forms, can be mild or severe

One of the more severe forms is known as One of the more severe forms is known as Cooley’s anemiaCooley’s anemia

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DyscrasiaDyscrasia– -crasia-crasia means blending means blending– Any pathologic condition of the formed elements of Any pathologic condition of the formed elements of

the bloodthe blood

HemochromatosisHemochromatosis– Chromat/oChromat/o means colour means colour– Genetic disorderGenetic disorder– Intestines absorb too much ironIntestines absorb too much iron– Iron accumulates in the organs and causes damageIron accumulates in the organs and causes damage

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SepticemiaSepticemia– AKA Blood PoisoningAKA Blood Poisoning

Presence of bacteria in the bloodPresence of bacteria in the blood– May be due to a spreading of another infectionMay be due to a spreading of another infection

Can be very serious – even fatalCan be very serious – even fatal

HyperlipidemiaHyperlipidemia– Elevated plasma concentrations of Elevated plasma concentrations of

cholesterol, triglycerides, and lipoproteinscholesterol, triglycerides, and lipoproteinsLipidLipid means fat means fat

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Polycythemia VeraPolycythemia Vera– When insufficient oxygen arrives at the When insufficient oxygen arrives at the

tissues, increased erythrocyte production is tissues, increased erythrocyte production is stimulatedstimulated

– Due to genetics or external conditions like Due to genetics or external conditions like increased elevationincreased elevation

Can result in elevated blood pressure, increased Can result in elevated blood pressure, increased viscosity of blood, increased susceptibility to clotsviscosity of blood, increased susceptibility to clots

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HemophiliaHemophilia– Phil/oPhil/o means attraction means attraction– Caused by hereditary deficiency of one of Caused by hereditary deficiency of one of

several clotting factors (ex Factor VIII or IX)several clotting factors (ex Factor VIII or IX)– Results in reduced ability to clot and eventual Results in reduced ability to clot and eventual

anemiaanemia

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Myelodysplastic SyndromeMyelodysplastic Syndrome– In the past was known as preleukemiaIn the past was known as preleukemia– Only about 30% of the cases progressOnly about 30% of the cases progress– Some of the hematopoietic tissue is Some of the hematopoietic tissue is

dysfunctional leading to a shortage of blood dysfunctional leading to a shortage of blood cellscells

-dysplasia-dysplasia means bad growth or development means bad growth or development

The Cardiovascular System: Blood

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