Download Erythrocytes

PowerPoint® Lecture Slides
prepared by
Leslie Hendon
University of Alabama,
Birmingham
CHAPTER
18
Part 1
Blood
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Blood Circulation
• Powered by the pumping action of the heart
• Functions of blood
• Carries respiratory gases
• nutrients
• hormones
• Helps body regulate temperature
• Blood volume
• Males: 5–6 liters
• Females: 4–5 liters
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Composition of Blood
• Contains cellular and liquid components
• A specialized connective tissue
• Blood cells—formed elements
• Plasma—fluid portion and fibrinogen
• Hematocrit—measure of % RBC
• Males: 47% ± 5%
• Females: 42% ± 5%
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Major Components of Whole Blood
Plasma
55% of whole blood
Least dense component
1 Withdraw
blood and place
in tube.
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2 Centrifuge the
blood sample.
Buffy coat
Leukocytes and platelets
<1% of whole blood
Erythrocytes
45% of whole blood
Most dense component
Formed
elements
Figure 18.1
Blood Plasma
• Straw-colored, sticky fluid portion of blood
• Approximately 90% water
• Contains over 100 kinds of molecules
• Ions—Na+ and Cl–
• Nutrients—Sugars, amino acids, lipids,
wastes, and proteins
• Three main proteins
• Albumin, globulins, and fibrinogen
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Platelets Erythrocytes Monocyte
Neutrophils
Lymphocyte
(b) Photomicrograph of a human blood
smear, Wright’s stain (715)
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Figure 18.2b
Erythrocytes
• Oxygen-transporting cells—7.5 µm in
diameter (diameter of capillary 8—10mm)
• Most numerous of the formed elements
• Females: 4.3–5.2 million cells/cubic millimeter
• Males: 5.2–5.8 million cells/cubic millimeter
• Have no organelles or nuclei
• Are the ideal measuring tool for estimating
sizes of nearby structures
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Erythrocytes
• Are packed with oxygen-carrying
hemoglobin
• Hemoglobin molecule bears four oxygen
molecules
• Each O2 molecule bears an iron molecule
• Oxidation of iron atoms of hemoglobin
molecules
• Gives blood its red color
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An Erythrocyte
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Figure 18.3
Leukocytes—White Blood Cells (WBCs)
• 4800–11,000/cubic millimeter
• Protect the body from infectious
microorganisms
• Function outside the bloodstream in loose
connective tissue
• Diapedesis—circulating leukocytes leave the
capillaries
• Originate in bone marrow
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Leukocytes—White Blood Cells (WBCs)
• Two types of leukocytes
• Granulocytes
• Agranulocytes
• Never Let Monkeys Eat Bananas
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Relative Percentages of the Different Types
of Leukocytes
Differential
WBC count
(All total 4800–
10,800/l)
Formed
elements
Platelets
Leukocytes
Granulocytes
Neutrophils (50–70%)
Eosinophils (2–4%)
Basophils (0.5–1%)
Erythrocytes
Agranulocytes
Lymphocytes (25–45%)
Monocytes (3–8%)
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Figure 18.5
Granulocytes
• Neutrophils—most
numerous WBC
• Phagocytize and
destroy bacteria
• Nucleus—has two to
six lobes
• Granules pick up
acidic and basic
stains
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Figure 18.4a
Granulocytes
• Eosinophils—compose
1–4% of all WBCs
• Play roles in
• Ending allergic
reactions, parasitic
infections
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Figure 18.4b
Granulocytes
• Basophils—about 0.5%
of all leukocytes
• Nucleus—usually two
lobes
• Granules secrete
histamines
• Function in
inflammation mediation
• Similar in function to
mast cells
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Figure 18.4c
Agranulocytes
• Lymphocytes—compose
20–45% of WBCs
• The most important cells
of the immune system
• Nucleus—stains dark
purple
• Effective in fighting
infectious organisms
• Act against a specific
foreign molecule
(antigen)
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Figure 18.4d
Agranulocytes
• Two main classes of lymphocyte
• T cells—attack foreign cells directly
• B cells—multiply to become plasma cells
• Secrete antibodies
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Agranulocytes
• Monocytes—compose
4–8% of WBCs
• The largest leukocytes
• Nucleus—kidney
shaped
• Transform into
macrophages
• Phagocytic cells
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Figure 18.4e
Platelets
• Cell fragments
• Break off from megakaryocytes
• Function in clotting of blood
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Summary of Formed Elements
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Table 18.1
Bone Marrow as the Site of Hematopoiesis
• Hematopoiesis—process by which blood
cells are formed in red marrow
• 100 billion new blood cells formed each day
• Bone marrow—located within all bones
• Red marrow—actively generates new blood
cells
• Contains immature erythrocytes
• In adults, red marrow is located
• Between trabeculae of spongy bone of axial skeleton
• Girdles
• Proximal epiphyses of humerus and femur
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Red Bone Marrow
Fat cells
Blood
sinusoids
Immature
blood cells
Spongy bone
(a) Location of red bone
marrow in spongy bone
(b) Micrograph of red bone
marrow (170)
Reticular
cell and fiber
Reticular
fibers of
fiber
network
Immature
blood cells
outside
sinusoids
Erythrocytes
in sinusoids
(c) Blood-forming cells in reticular
connective tissue around the
sinusoids (640)
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Figure 18.7
Cell Lines in Blood Cell Formation
• All blood cells originate in bone marrow
• All originate from one cell type
• 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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Stages of Differentiation of Blood Cells
Blood stem cell
Lymphoid stem cell
Myeloid stem cell
Proerythroblast
Early erythroblast
Myeloblasts
Monoblast
Promyelocytes
Megakaryoblast
Promonocyte
Promegakaryocyte
Eosinophilic Basophilic Neutrophilic
myelocyte myelocyte myelocyte
Late erythroblast
Normocyte
Eosinophilic Basophilic Neutrophilic
metametametamyelocyte myelocyte myelocyte
Megakaryocyte
Neutrophilic
band cell
Reticulocyte
Erythrocyte
Eosinophil Basophil
Neutrophil
Monocyte
Platelets
B lymphocyte T lymphocyte
Granular leukocytes
Wandering macrophage
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Figure 18.8