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Transportation Blood Carries oxygen to tissues Carries carbon dioxide from tissues Transports nutrients and other substances to cells Transports waste products from cells Carries hormones to organs
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Cardiovascular & Hematological Systems
Chapter 6Pathology
Circulatory Systemcirculatory system - the heart, blood vessels and
bloodcardiovascular system - the heart and blood vesselshematology – the study of blood functions of circulatory system
◦ transport O2, CO2, nutrients, wastes, hormones
◦ protection limit spread of infection, destroy microorganisms
and cancer cells, and initiates clotting◦ regulation
fluid balance, stabilizes pH of ECF, and temperature control
TransportationBloodCarries oxygen to tissuesCarries carbon dioxide from
tissuesTransports nutrients and other
substances to cellsTransports waste products from
cellsCarries hormones to organs
RegulationBloodBuffers keep pH of body fluids
between 7.35 and 7.45Substances maintain osmotic
pressure to regulate fluid in tissues (fluid balance)
Transports heat generated in muscles to aid in regulation of body temperature
ProtectionBloodCarries cells and antibodies of
immune systemCarries factors to protect against
blood loss
Components and General Properties of Bloodadults have 4-6 L of blooda liquid connective tissue consisting
of cells and extracellular matrix◦plasma – matrix of blood a clear, light yellow fluid
◦formed elements - blood cells and cell fragments red blood cells, white blood cells, and
platelets
Components and General Properties of Bloodseven kinds of formed elements
◦erythrocytes - red blood cells (RBCs)◦Platelets - thrombocytes
cell fragments from special cell in bone marrow
◦leukocytes - white blood cells (WBCs) five leukocyte types divided into two
categories: granulocytes (with granules)
neutrophils eosinophils basophils
agranulocytes (without granules) lymphocytes monocytes
Formed Elements of Blood
Neutrophil
Erythrocyte
Eosinophil
Monocyte
NeutrophilBasophil
Neutrophil
Platelets
MonocyteSmalllymphocyte
Young (band)neutrophil
Smalllymphocyte
Largelymphocyte
Separating Plasma From Formed Elements of Blood
hematocrit (packed cell vol.)- centrifuge blood to separate components◦erythrocytes are
heaviest and settle first 37% to 52% total volume
(hematocrit)◦leukocytes and platelets
1% total volume; buffy coat◦plasma
the remainder of volume 47% - 63%
Centrifuge
Withdrawblood
Plasma(55% of whole blood)
Buffy coat: leukocytesand platelets(<1% of whole blood)
Erythrocytes(45% of whole blood)
Formedelements
Plasma and Plasma Proteins
plasma – liquid portion of blood3 major categories of plasma
proteins◦albumins – smallest and most
abundant◦globulins (antibodies)
provide immune system functions alpha, beta and gamma globulins
◦fibrinogen precursor of fibrin threads that help form
blood clots
Percentages show the relative proportions of the different components of plasma and formed elements.
Composition of Whole BloodComposition of Whole Blood
Blood Plasma
Plasma is 55% of blood91% water8% protein
◦ Albumin◦ Clotting factors◦ Antibodies◦ Complement
•1% other materials–Glucose–Amino acids–Lipids–Electrolytes–Vitamins–Hormones–Wastes–Drugs–Dissolved gases
Hemopoiesisadult production of 400 billion platelets, 200
billion RBCs and 10 billion WBCs every dayhemopoiesis – the production of blood,
especially its formed elementshemopoietic tissues produce blood cells
◦yolk sac produces stem cells for first blood cells colonize fetal bone marrow, liver, spleen and
thymus◦liver stops producing blood cells at birth◦spleen remains involved with lymphocyte
production◦red bone marrow produces all seven formed
elements
The Formed ElementsThe Formed ElementsProduced in red bone marrowHematopoietic (blood-forming)
stem cells can develop into any blood cell
Short-lived tissue cells
ErythrocytesRed blood cells (RBCs) most
numerousMature cells anuclearContain hemoglobin
◦Binds to oxygen for transport◦Carries hydrogen ions for buffering◦Carries carbon dioxide for
elimination
Erythrocytes (RBCs)
Erythrocytes (RBCs)Erythrocytes are an example of the
complementarity of structure and function
Structural characteristics contribute to its gas transport function◦Biconcave shape has a huge surface area
relative to volume◦Erythrocytes are more than 97% hemoglobin◦ATP is generated anaerobically, so the
erythrocytes do not consume the oxygen they transport
Erythrocyte FunctionRBCs are dedicated to respiratory gas
transportHb reversibly binds with oxygen and most
oxygen in the blood is bound to HbHb is composed of the protein globin,
made up of two alpha and two beta chains, each bound to a heme group
Each heme group bears an atom of iron, which can bind to one oxygen molecule
Each Hb molecule can transport four molecules of oxygen
Erythrocytes and Erythrocytes and HemoglobinHemoglobin RBC count and hemoglobin concentration indicate amount of O2 blood can carry◦ hematocrit (packed cell volume) – percentage of
whole blood volume composed of red blood cells men 42- 52% cells; women 37- 48% cells
◦ hemoglobin concentration of whole blood higher in men
◦ RBC count higher in men Why values are lower in women
◦ androgens stimulate RBC production ◦ women have periodic menstrual losses◦ hematocrit is inversely proportional to percentage of
body fat
Hemoglobin (Hb)Oxyhemoglobin – Hb bound to
oxygen◦Oxygen loading takes place in the lungs
Deoxyhemoglobin – Hb after oxygen diffuses into tissues (reduced Hb)
Carbaminohemoglobin – Hb bound to carbon dioxide ◦Carbon dioxide loading takes place in
the tissues
Production of ErythrocytesHematopoiesis – blood cell
formationHematopoiesis occurs in the red
bone marrow of the:◦Axial skeleton and girdles◦Epiphyses of the humerus and femur
Hemocytoblasts give rise to all formed elements
Hormonal Control of ErythropoiesisErythropoietin (EPO) release by the
kidneys is triggered by:◦Hypoxia due to decreased RBCs◦Decreased oxygen availability◦Increased tissue demand for oxygen
Enhanced erythropoiesis increases the: ◦RBC count in circulating blood◦Oxygen carrying ability of the blood
Homeostasis: Normal blood oxygen levels
IncreasesO2-carryingability of blood
Erythropoietinstimulates redbone marrow
Reduces O2 levelsin blood
Kidney (and liver to a smallerextent) releases erythropoietin
Enhancederythropoiesisincreases RBC count
Stimulus: Hypoxia due todecreased RBC count,decreased amount of hemoglobin, or decreased availability of O2
Start
Imbalance
Imbalance
Erythropoietin Mechanism
Erythrocyte HomeostasisErythrocyte Homeostasis negative feedback control
◦ drop in RBC count causes kidney hypoxia
◦ kidney production of EPO stimulates bone marrow
◦ RBC count increases in 3 - 4 days
stimuli for increasing erythropoiesis◦ low levels O2 (hypoxemia)◦ high altitude◦ increase in exercise◦ loss of lung tissue in emphysema
leaves
Hypoxemia(inadequate O2 transport)
Sensed by liver and kidneys
Secretion oferythropoietin
Acceleratederythropoiesis
IncreasedRBC count
IncreasedO2 transport
Stimulation ofred bone marrow
ErythrocyteErythrocyte Disorders Disorders polycythemia - an excess of RBCs
◦ primary polycythemia (polycythemia vera) cancer of erythropoietic cell line in red bone marrow
RBC count as high as 11 million/L; hematocrit 80%
◦ secondary polycythemia from dehydration, emphysema, high altitude, or
physical conditioning RBC count up to 8 million/L
dangers of polycythemia◦ increased blood volume, pressure, viscosity
can lead to embolism, stroke or heart failure
AnemiaAnemiacauses of anemia fall into three categories:
◦ inadequate erythropoiesis or hemoglobin synthesis kidney failure and insufficient erythropoietin iron-deficiency anemia inadequate vitamin B12 from poor nutrition or
lack of intrinsic factor (pernicious anemia) hypoplastic anemia – slowing of
erythropoiesis aplastic anemia - complete cessation of
erythropoiesis◦ hemorrhagic anemias from bleeding◦ hemolytic anemias from RBC destruction
AnemiaAnemiaanemia has three potential
consequences:◦tissue hypoxia and necrosis
patient is lethargic shortness of breath upon exertion life threatening necrosis of brain, heart, or
kidney◦blood osmolarity is reduced producing
tissue edema◦blood viscosity is low
heart races and pressure drops cardiac failure may ensue
Blood TypesBlood Typesblood types and transfusion
compatibility are a matter of interactions between plasma proteins and erythrocytes
blood types are based on interactions between antigens and antibodies
Blood Antigens and Blood Antigens and AntibodiesAntibodies
antigens◦complex molecules on surface of cell
membrane that are unique to the individual used to distinguish self from foreign foreign antigens generate an immune
response agglutinogens – antigens on the
surface of the RBC that is the basis for blood typing
Blood Antigens and Blood Antigens and AntibodiesAntibodies
antibodies◦proteins (gamma globulins) secreted by
plasma cells part of immune response to foreign
matter bind to antigens and mark them for
destruction forms antigen-antibody complexes agglutinins – antibodies in the plasma
that bring about transfusion mismatch
ABO GroupABO Groupyour ABO blood type is determined
by presence or absence of antigens (agglutinogens) on RBCs◦blood type A person has A antigens◦blood type B person has B antigens◦blood type AB has both A and B antigens◦blood type O person has neither antigen
most common - type O rarest - type AB
Universal Donors and Universal Donors and RecipientsRecipientsSafest transfusion is same blood typeuniversal donor
◦Type O – most common blood type◦lacks RBC antigens◦donor’s plasma may have both antibodies
against recipient’s RBCs (anti-A and anti-B) may give packed cells (minimal plasma)
universal recipient ◦Type AB – rarest blood type◦lacks plasma antibodies; no anti- A or B
Labels on the bottles denote the kind of antiserum (antibodies) added to the blood samples.
Anti-A serum agglutinates (causes to clump) red cells in type A blood, but anti-B serum does not.
Anti-B serum agglutinates red cells in type B blood, but anti-A serum does not. Both sera agglutinate type AB blood cells, and neither serum agglutinates type O blood
Blood TypingBlood Typing
Type A
Type B
Type AB
Type O
LeukocytesLeukocytesWhite blood cells (WBCs) colorless, round
◦Granulocytes Neutrophils (polymorphs) Eosinophils Basophils
◦Agranulocytes Lymphocytes Monocytes
Prominent nuclei Clear body of foreign material, cellular
debris, pathogens
HemostasisHemostasisPrevents blood loss when blood
vessel rupturesContraction of smooth muscles in
blood vessel wall (vasoconstriction)
Formation of platelet plugFormation of blood clot
Uses of Blood and Blood Uses of Blood and Blood ComponentsComponentsBlood stored in blood banks up to
35 days◦Anti-clotting solution added◦Expiration date added
Blood donated before elective surgery (autologous blood)
Whole Blood TransfusionsUsed for loss of large volume of
bloodMassive hemorrhage from serious
injuriesDuring internal bleedingDuring or after an operationBlood replacement in treatment of
HDN
Use of PlasmaReplace blood volumeTreat circulatory failure (shock)Treat plasma protein deficiencyReplace clotting factorsProvide needed antibodies
Blood DisordersBlood DisordersBlood abnormalitiesAnemia (low level of hemoglobin
or red cells)Leukemia (increase in white cells)Clotting disorders (abnormal
tendency to bleed)
AnemiaAnemia causesExcessive loss or destruction of red cells
◦Hemorrhagic anemia◦Hemolytic anemia◦Sickle cell anemia
Impaired production of red cells or hemoglobin◦Deficiency anemia◦Thalassemia◦Bone marrow suppression
LeukemiaLeukemia is characterized by
enormous increase in white cellsMyelogenous leukemia from bone
marrowLymphocytic leukemia from
lymphoid tissueBone marrow transplants sometimes
successful in restoring blood-producing stem cells lost after leukemia treatment
Clotting DisordersAbnormal bleeding through
disruption of coagulation processHemophiliaVon Willebrand diseaseThrombocytopeniaDisseminated intravascular
coagulation (DIC)
The Blood Slide (Smear)Complete blood count (CBC)
performed on drop stained blood slide
Red cells examinedPlatelets examinedParasites may be foundDifferential white count performed