The Circulatory The Circulatory SystemSystem
BloodBlood
Anatomy & Physiology IIChapter 13
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
Transportation
BloodCarries oxygen to tissuesCarries carbon dioxide from
tissuesTransports nutrients and other
substances to cellsTransports waste products from
cellsCarries hormones to organs
Regulation
Blood
Buffers keep pH of body fluids between 7.35 and 7.45
Substances maintain osmotic pressure to regulate fluid in tissues (fluid balance)
Transports heat generated in muscles to aid in regulation of body temperature
Protection
BloodCarries cells and antibodies of
immune systemCarries factors to protect against
blood loss
Components and General Properties of Blood
adults 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
Neutrophil
Basophil
Neutrophil
Platelets
Monocyte
Smalllymphocyte
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 blood
91% water
8% 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 Elements
Produced in red bone marrow
Hematopoietic (blood-forming) stem cells can develop into any blood cell
Short-lived tissue cells
Erythrocytes
Red blood cells (RBCs) most numerous
Mature 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
transport
Hb reversibly binds with oxygen and most oxygen in the blood is bound to Hb
Hb 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
Hemoglobin (Hb) StructureHemoglobin (Hb) Structureeach Hb molecule consists
of:◦ four protein chains – globins ◦ four heme groups
heme groups◦ nonprotein component that
binds O2 to ferrous ion (Fe2+) at its center
◦ Fe is the symbol for ironglobins - four protein chains
◦ two alpha and two beta chains◦ 5% CO2 in blood is bound to
globin moietyadult vs. fetal hemoglobin
(a)
(b)
C
CH3
C
C
C
CC
C
C
CC
CC
N
N
NN
CH
CH
CH
CH
CH2
COOH
CH3 CH3
CH2
CH2
CH2
COOH
CH2 CH3
HC
C
C C
CHC
Fe2+
CH2
Beta
Alpha
Alpha
Beta
Hemegroups
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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
Production of Erythrocytes: Erythropoiesis
Regulation and Requirements for ErythropoiesisCirculating erythrocytes – the number
remains constant and reflects a balance between RBC production and destruction◦Too few RBCs leads to tissue hypoxia
◦Too many RBCs causes undesirable blood viscosity
Erythropoiesis is hormonally controlled and depends on adequate supplies of iron, amino acids, and B vitamins
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 Homeostasisnegative 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
Erythrocytes Death and Erythrocytes Death and DisposalDisposalRBCs lyse in narrow channels in spleenmacrophages in spleen
◦digest membrane bits◦separate heme from globin
globins hydrolyzed into amino acids iron removed from heme
heme pigment converted to biliverdin then to bilirubin (yellow)
bilirubin released into blood plasma (kidneys - yellow urine)
liver removes bilirubin and secretes into bile- concentrated in gall bladder: released into small
intestine; bacteria create urobilinogen (brown feces)
Erythrocytes Erythrocytes Recycle/DisposalRecycle/Disposal
Small intestine
GlobinHeme
IronBiliverdin
Bilirubin
Bile
Feces
Storage Reuse Loss bymenstruation,
injury, etc.
Amino acidsIronFolic acidVitamin B12
Nutrientabsorption
Erythrocytescirculate for
120 days
Expired erythrocytesbreak up in liver and spleen
Cell fragmentsphagocytized
Erythropoiesis inred bone marrow
Hemoglobindegraded
Hydrolyzed to freeamino acids
ErythrocyteErythrocyte Disorders Disorderspolycythemia - 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
Sickle-Cell DiseaseSickle-Cell Diseasehereditary hemoglobin defects
that occur mostly among people of African descent
caused by a recessive allele that modifies the structure of the hemoglobin molecule (HbS)◦ differs only on the sixth amino
acid of the beta chain◦ HbS does not bind oxygen well◦ RBCs become rigid, sticky, pointed
at ends◦ clump together and block small
blood vessels causing intense pain◦ can lead to kidney or heart failure,
stroke, rheumatism or paralysis
7 µm
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
Blood TypesBlood Types
RBC antigens called agglutinogens◦called antigen A and
B◦determined by
carbohydrate components found on RBC surface
antibodies called agglutinins◦found in plasma◦anti-A and anti-B
leaves
Type O Type B
Type A Type AB
Galactose
Fucose
N-acetylgalactosamine
Key
ABO GroupABO Group
your 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
Plasma AntibodiesPlasma Antibodiesantibodies (agglutinins); anti-A and anti-
Bappear 2-8 months after birth; at
maximum concentration at 10 yr.◦ antibody-A and/or antibody-B (both or none)
are found in plasma you do not form antibodies against your antigens
agglutination ◦ each antibody can attach to several foreign
antigens on several different RBCs at the same time
responsible for mismatched transfusion reaction◦ agglutinated RBCs block small blood vessels,
hemolyze, and release their hemoglobin over the next few hours or days
◦ Hb blocks kidney tubules and causes acute renal failure
Agglutination of Agglutination of ErythrocytesErythrocytes
Antibodies(agglutinins)
Transfusion ReactionTransfusion Reaction
leaves
Blood fromtype A donor
Agglutinated RBCsblock small vessels
Donor RBCsagglutinated byrecipient plasma
Type B(anti-A)recipient
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
Testing for Blood TypeBlood sera containing antibodies
to A or B antigens (antisera) prepared
Sera added to blood sample
Corresponding red cells clump (agglutination)
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.
ZOOMING IN • Can you tell from these
reactions whether these cells are Rh positive or Rh negative?
Blood TypingBlood Typing
Type A
Type B
Type AB
Type O
The Rh FactorRed cell antigen group Rh (D antigen)
◦Rh-positive blood has antigen
◦Rh-negative blood lacks antigen
Rh incompatibility can lead to hemolytic disease of newborn (HDN)
Anti-D agglutinins not normally present◦form in Rh- individuals exposed to Rh+ blood
Rh- woman with an Rh+ fetus or transfusion of Rh+ blood
no problems with first transfusion or pregnancy
Hemolytic Disease of Hemolytic Disease of NewbornNewbornoccurs if Rh- mother has formed
antibodies and is pregnant with second Rh+ child◦Anti-D antibodies can cross placenta
prevention◦RhoGAM given to pregnant Rh- women
binds fetal agglutinogens in her blood so she will not form Anti-D antibodies
Hemolytic Disease of Hemolytic Disease of NewbornNewborn
Rh antibodies attack fetal blood causing severe anemia and toxic brain syndrome
leaves
Uterus
Placenta
Rh mother
(a) First pregnancy (b) Between pregnancies (c) Second pregnancy
Rhantigen
Rh+ fetus
Amniotic sacand chorion
Anti-Dantibody
SecondRh+ fetus
LeukocytesLeukocytesWhite blood cells (WBCs) colorless,
round◦Granulocytes
Neutrophils (polymorphs) Eosinophils Basophils
◦Agranulocytes Lymphocytes Monocytes
Prominent nuclei Clear body of foreign material, cellular
debris, pathogens
(A) A phagocytic leukocyte (white blood cell) squeezes through a capillary wall in the region of an infection and engulfs a bacterium.
(B) The bacterium is enclosed in a vesicle and digested by a lysosome.
ZOOMING IN • What type of epithelium makes up the capillary wall?
Phagocytosis Phagocytosis
Components of Whole Blood
Platelets
Platelets (thrombocytes)Smallest formed elementNot cells—no nuclei or DNAFragments release from
megakaryocytesEssential for blood coagulation
(clotting)
HemostasisHemostasisPrevents blood loss when blood
vessel rupturesContraction of smooth muscles in
blood vessel wall (vasoconstriction)
Formation of platelet plugFormation of blood clot
Blood ClottingProcoagulants: compounds that
promote clottingAnticoagulant: compounds that
prevent clottingFinal steps in clotting:
◦Damaged tissues release substances that form prothrombinase
◦Prothrombinase converts prothrombin to thrombin
◦Thrombin converts fibrinogen to fibrin◦Fibrin forms network of threads to
form clot
Blood Clotting (cont’d)Serum: fluid left over after
clotting takes placePlasma = serum + clotting
factors
Coagulation DisordersCoagulation Disordersthrombosis - abnormal clotting in
unbroken vessel
◦thrombus - clot most likely to occur in leg veins of inactive
people
◦ pulmonary embolism - clot may break free, travel from veins to lungs
embolus – anything that can travel in the blood and block blood vessels
infarction (tissue death) may occur if clot blocks blood supply to an organ (MI or stroke)◦ 650,000 Americans die annually of
thromboembolism – traveling blood clots
Properties of Bloodviscosity - resistance of a fluid to flow
◦ whole blood 4.5 - 5.5 times as viscous as water
◦ plasma is 2.0 times as viscous as water important in circulatory function
osmolarity of blood - the total molarity of those dissolved particles that cannot pass through the blood vessel wall◦ if too high, blood absorbs too much water,
increasing the blood pressure◦ if too low, too much water stays in tissue,
blood pressure drops and edema occurs◦ optimum osmolarity is achieved by bodies
regulation of sodium ions, proteins, and red blood cells.
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 Transfusions
Used for loss of large volume of blood
Massive hemorrhage from serious injuries
During internal bleeding
During or after an operation
Blood replacement in treatment of HDN
Use of Blood Components
Centrifuge separates plasma from formed elements
Hemapheresis—keep desired elements and return remainder to donor
Plasmapheresis—keep plasma and return formed elements to donor
Use of PlasmaReplace blood volume
Treat circulatory failure (shock)
Treat plasma protein deficiency
Replace clotting factors
Provide needed antibodies
Blood DisordersBlood Disorders
Blood 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 Disorders
Abnormal bleeding through disruption of coagulation process
HemophiliaVon Willebrand diseaseThrombocytopeniaDisseminated intravascular
coagulation (DIC)
Blood StudiesBlood StudiesSome blood tests are standard
part of routine physical examination
Machines can perform several tests simultaneously
The HematocritPacked cell volume (% of RBC in
whole blood)
Performed in centrifuge
Adult range for men 42%–54%
Adult range women 36%–46%
Hemoglobin Tests
Mass (in grams) of hemoglobin per 100 mL of whole blood
Performed by electrophoresis
Adult range for men 14–17 g
Adult range for women 12–15 g
Blood Cell CountsRed cell counts
◦Range 4.5–5.5 million cells per microliter (μL)
White cell counts
◦Range 5,000–10,000 cells per microliter (μL)
Platelet counts
◦Range 150,000–450,000 per microliter (μL)
The Blood Slide (Smear)
Complete blood count (CBC) performed on drop stained blood slide
Red cells examined
Platelets examined
Parasites may be found
Differential white count performed
Blood Chemistry TestsBatteries of blood serum tests often
done by machineElectrolytesBlood glucoseNitrogenous waste productsCreatineEnzymesLipidsPlasma proteinsHormonesVitaminsAntibodiesDrug levels
Coagulation StudiesPerformed before surgery and
during treatment of certain diseases
Amounts of clotting factors
Bleeding time
Clotting time
Capillary strength
Platelet function
Bone Marrow BiopsySample of red marrow through
needle from sternum, sacrum, or iliac crest
Used in diagnosing bone marrow disorders
◦Leukemia
◦Some types of anemia
End of Presentation
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