© 2014 pearson education, inc. blood. © 2014 pearson education, inc. blood circulation circulatory...
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© 2014 Pearson Education, Inc.
Blood
© 2014 Pearson Education, Inc.
Blood Circulation
• Circulatory system is divided into
• Cardiovascular system
• Lymphatic system
• Blood
• Transport mechanism for
• Nutrients
• Signaling molecules
• Respiratory gases
• Waste products
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Blood Circulation
• Powered by the pumping action of the heart
• Oxygen and nutrients diffuse across capillary walls to body tissues
• Regulates body temperature
Composition of Blood
• Blood has cellular and liquid components
• Is a specialized connective tissue
• Blood cells—formed elements
• Plasma—liquid portion of blood
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Composition of Blood
• Hematocrit
• Is the measure of % RBC
• Males: 47% ± 5%
• Females: 42% ± 5%
• Buffy coat
• Is portion of blood composed of leukocytes and platelets
• Present at junction of plasma and RBCs
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Figure 18.1 Major components of whole blood.
Withdraw bloodand place in tube.
Centrifuge theblood sample.
55% of whole bloodLeast dense component
Leukocytes and platelets1% of whole blood
45% of whole bloodMost dense component
Plasma
Buffy coat
Erythrocytes Formedelements
21
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Blood Plasma
• Clear, sticky fluid portion of blood
• Approximately 90% water
• Contains over 100 kinds of molecules
• Ions—Na+ and Cl–
• Nutrients
• Sugars, amino acids, lipids
• Wastes
• Carbon dioxide, urea, ammonia
• Proteins
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Blood Plasma
• Three main proteins
• Albumin
• Prevents water from diffusing out of blood vessels
• Globulins
• Include antibodies and blood proteins that transport lipids, iron, and copper
• Fibrinogen
• One of the molecules involved in chemical reactions for blood clotting
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Figure 18.2b Blood cells.
Erythrocytes Platelets
Monocyte Lymphocyte Neutrophil Eosinophil
Photomicrograph of a human blood smear,Wright’s stain (610)
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Erythrocytes
• Most numerous of the formed elements
• Have no organelles or nuclei
• Are packed with oxygen-carrying hemoglobin
• Hemoglobin molecule bears four oxygen molecules
• Each O2 bears an Fe
• Iron atoms give blood it’s red color
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Figure 18.3 Structure of erythrocytes.
Side view (cut)
Top view
2.5 m
7.5 m
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Leukocytes—White Blood Cells (WBCs)
• Protect the body from infectious microorganisms
• Function outside the bloodstream in loose connective tissue
• Originate in bone marrow
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Neutrophils (50–70%)
Eosinophils (2–4%)
Basophils (0.5–1%)
Lymphocytes (25–45%)
Monocytes (3–8%)
Platelets
Leukocytes
Erythrocytes
Formedelements(not drawnto scale)
DifferentialWBC count(All total 4800–10,800 cells/l)
Mnemonic: “Never Let Monkeys Eat Bananas”
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Granulocytes
• Neutrophils
• Most numerous WBC
• First line of defense in inflammatory response
• Phagocytize and destroy bacteria
Granulocytes
Neutrophil:Multilobednucleus, palered and bluecytoplasmicgranules
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Granulocytes
• Eosinophils
• 1–4% of all WBCs
• Play a role in ending allergic reactions by phagocytizing allergens
• Secrete enzymes that degrade histamines
Granulocytes
Eosinophil:Bilobednucleus, redcytoplasmicgranules
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Granulocytes
• Basophils-0.5% of all leukocytes
• Function in inflammation mediation
• Direct later stages of inflammation in allergies and parasitic infections
Granulocytes
Basophil:Bilobednucleus, purplish-blackcytoplasmicgranules
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Agranulocytes
Lymphocytes—~35% of WBCs
• The most important cells of the immune system
• Fighting infectious organisms
• Act against a specific foreign molecule (antigen)
• 2 types of lymphocytes
• T cells—attack foreign cells directly
• B cells—multiply to become plasma cells
Agranulocytes
Lymphocyte(small): Largesphericalnucleus, thinrim of paleblue cytoplasm
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Agranulocytes
• Monocytes—compose 4–8% of WBCs
• The largest leukocytes
• Transform into macrophages
• Phagocytic cells
Agranulocytes
Monocyte:Kidney-shapednucleus,abundant paleblue cytoplasm
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Platelets
• Cell fragments
• Break off from megakaryocytes
• Function in clotting of blood
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Table 18.1 Summary of Formed Elements of the Blood (1 of 2)
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Table 18.1 Summary of Formed Elements of the Blood (2 of 2)
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Blood Cell Formation
• Hematopoiesis—process by which blood cells are formed in red marrow
• 100 billion new blood cells formed each day
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Bone Marrow as the Site of Hematopoiesis
• Bone marrow—located within all bones
• Red marrow—actively generates new blood cells
• Contains immature erythrocytes
• In adults, in red marrow
• Yellow marrow—dormant
• Contains many fat cells
• Located in the long bones of adults
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Cell Lines in Blood Cell Formation
• All blood cells originate in bone marrow
• All originate from one cell type
• Hemopoietic blood stem cell (pluripotential hematopoeitic stem cell)
• Lymphoid stem cells
• Give rise to lymphocytes
• Myeloid stem cells
• Give rise to all other blood cells
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Disorders of the Blood
• Disorders of erythrocytes
• Polycythemia
• Abnormal excess of erythrocytes
• Anemia
• Erythrocyte levels or hemoglobin concentrations are low
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Disorders of the Blood
• Disorders of erythrocytes (continued)
• Sickle cell disease
• Inherited condition
• Results from a defective hemoglobin molecule
• Erythrocytes distort into a sickle shape
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Disorders of the Blood
• Disorders of leukocytes
• Leukemia—a form of cancer
• Classified as lymphoblastic or myeloblastic
• Disorders of platelets
• Thrombocytopenia
• Abnormally low concentration of platelets