3. Copyright 2010, John Wiley & Sons, Inc.
Composition
■ A connective tissue with components readily
seen when blood is centrifuged:
❑ Plasma(~55%): soluble materials (mostly
water); lighter so at top of tube
❑ Formed elements (~45%): cells (heavier so at
bottom of tube)
■ Mostly red blood cells (RBCs)
❑ Percent of blood occupied by RBCs = hematocrit (Hct)
❑ Normal hematocrit value: 42-47%
▪ Females: 38 to 46%; males: 40 to 54%
■ Buffy coat: site of white blood cells (WBCs), platelets
6. Copyright 2010, John Wiley & Sons, Inc.
Plasma: Liquid Portion of Blood
■ Water: 91.5%
■ Plasma proteins: 7%
❑ Albumin (54%): function in osmosis; carriers
❑ Globulins (38%): serve as antibodies
❑ Fibrinogen (7%): important in clotting
■ Other: 1.5%
❑ Electrolytes, nutrients, gases, hormones,
vitamins, waste products
7. Copyright 2010, John Wiley & Sons, Inc.
Formed Elements
I. Red Blood Cells (RBCs)
II. White blood cells (WBCs)
A. Granular leukocytes
1. Neutrophils
2. Eosinophils
3. Basophils
B. Agranular leukocytes
1. Lymphocytes and natural killer (NK) cells
2. Monocytes
III Platelets
8. Copyright 2010, John Wiley & Sons, Inc.
Formation of Blood Cells
■ Called hemopoiesis or hematopoiesis
■ Occurs throughout life
❑ In response to specific hormones, stem cells
undergo a series of changes to form blood cells
■ Pluripotent stem cells in red marrow
❑ Lymphoid stem cells lymphocytes (in lymphatic
tissues)
❑ Myeloid stem cells all other WBCs, all RBCs,
and platelets (in red bone marrow)
11. Copyright 2010, John Wiley & Sons, Inc.
Erythrocytes (RBCs)
■ Hemoglobin (red pigment)
❑ Carries 98.5% of O2
and 23% of CO2
■ RBC count: about 5 million/µl
❑ Male: 5.4 million cells/µl; female: 4.8 million/µl
■ Structure of mature RBC
❑ No nucleus/DNA so RBCs live only 3 to 4 mos
❑ Lack of nucleus causes biconcave disc shape with
extensive plasma membrane
■ Provides for maximal gas exchange
■ Is flexible for passing through capillaries
12. Copyright 2010, John Wiley & Sons, Inc.
RBC Recycling
■ Cleared by macrophages (liver and spleen)
■ Recycled components
❑ Globin amino acids recycled to form proteins
❑ Heme broken down into:
■ Fe
❑ Carried in blood by transferrin (“protein escort” of Fe)
❑ Recycled in bone marrow for forming synthesis of new
hemoglobin; proteins and vitamin B12
required also
■ Non-Fe portion of heme biliverdin bilirubin
❑ Bilirubin to liver bile helps absorb fats
❑ Intestinal bacteria convert bilirubin into other chemicals
that exit in feces (stercobilin) or urine (urobilin)
13. Copyright 2010, John Wiley & Sons, Inc.
Red blood
cell
death and
phagocytosis
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
1
Globin
Red blood
cell
death and
phagocytosis
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
Hem
e
2
1
Amino
acids
Reused for
protein synthesis
Globin
Red blood
cell
death and
phagocytosis
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
Hem
e
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
Hem
e
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Live
r
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
Fe3+
7
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Circulation for about
120 days
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Erythropoiesis
in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
Fe3+
8
7
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Circulation for about
120 days
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Erythropoiesis
in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
Biliverdi
n
Bilirubi
n
Fe3+
9
8
7
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Circulation for about
120 days
Bilirubi
n
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Erythropoiesis
in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
Biliverdi
n
Bilirubi
n
Fe3+
1
0
9
8
7
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Stercobili
n
Bilirubi
n
Urobilinogen
Fece
s
Small
intestine
Circulation for about
120 days
Bacteria
Bilirubi
n
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Erythropoiesis
in
red bone marrow
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Hem
e
Biliverdi
n
Bilirubi
n
Fe3+
1
2
1
1
1
0
9
8
7
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Urin
e
Stercobili
n
Bilirubi
n
Urobilinogen
Fece
s
Small
intestine
Circulation for about
120 days
Bacteria
Bilirubi
n
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Erythropoiesis
in
red bone marrow
Kidne
y
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Urobilin
Hem
e
Biliverdi
n
Bilirubi
n
Fe3+
1
3
1
2
1
1
1
0
9
8
7
6
5
4
3
2
1
Amino
acids
Reused for
protein synthesis
Globin
Urin
e
Stercobili
n
Bilirubi
n
Urobilinogen
Fece
s
Large
intestine
Small
intestine
Circulation for about
120 days
Bacteria
Bilirubi
n
Red blood
cell
death and
phagocytosis
Transferrin
Fe3+
Fe3+
Transferrin
Live
r
+
Globin
+
Vitamin B12
+
Erythopoietin
Key:
in
blood
in
bile
Erythropoiesis
in
red bone marrow
Kidne
y
Macrophage in
spleen, liver, or
red bone marrow
Ferritin
Urobilin
Hem
e
Biliverdi
n
Bilirubi
n
Fe3+
1
4
1
3
1
2
1
1
1
0
9
8
7
6
5
4
3
2
1
Formation and Destruction of RBC’s
14. Copyright 2010, John Wiley & Sons, Inc.
RBC Synthesis: Erythropoiesis
■ Develop from myeloid stem cells in red
marrow
■ Cells lose nucleus; are then released into
bloodstream as reticulocytes
❑ These almost-mature RBCs develop into erythrocytes
after 1-2 days in bloodstream
❑ High reticulocyte count (> normal range of 0.5% to
1.5% as more of these circulate in bloodstream)
indicates high rate of RBC formation
15. Copyright 2010, John Wiley & Sons, Inc.
RBC Synthesis: Erythropoiesis
■ Production and destruction: normally
balanced
❑ Stimulus for erythropoiesis is low O2
delivery
(hypoxia) in blood passing to kidneys
❑ Kidneys release erythropoietin release (EPO)
❑ Stimulates erythropoiesis in red marrow
increased O2
delivery in blood (negative
feedback mechanism)
16. Copyright 2010, John Wiley & Sons, Inc.
RBC Synthesis: Erythropoiesis
■ Signs of lower-than-normal RBC count
changes in skin, mucous membranes, and
finger nail beds
❑ Cyanosis: bluish color
❑ Anemia: pale color
18. Copyright 2010, John Wiley & Sons, Inc.
White Blood Cells (WBCs or Leukocytes)
■ Appear white because lack hemoglobin
■ Normal WBC count: 5,000-10,000/µl
❑ WBC count usually increases in infection
■ Two major classes based on presence or
absence of granules (vesicles) in them]
❑ Granular: neutrophils, eosinophils, basophils
■ Neutrophils usually make up 2/3 of all WBCs
❑ Agranular: lymphocytes, monocytes
■ Major function: defense against
❑ Infection and inflammation
❑ Antigen-antibody (allergic) reactions
19. Copyright 2010, John Wiley & Sons, Inc.
White Blood Cell Functions
■ Neutrophils: first responders to infection
❑ Phagocytosis
❑ Release bacteria-destroying enzyme lysozyme
■ Monocytes macrophages (“big eaters”)
❑ Known as wandering macrophages
■ Eosinophils
❑ Phagocytose antibody-antigen complexes
❑ Help suppress inflammation of allergic reactions
❑ Respond to parasitic infections
20. Copyright 2010, John Wiley & Sons, Inc.
White Blood Cell Functions
■ Basophils
❑ Intensify inflammatory responses and allergic
reactions
❑ Release chemicals that dilate blood vessels:
histamine and serotonin; also heparin
(anticoagulant)
21. Copyright 2010, John Wiley & Sons, Inc.
White Blood Cell Functions
■ Lymphocytes
❑ Three types of lymphocytes
■ T cells
■ B cells
■ Natural killer (NK) cells
❑ Play major roles in immune responses
■ B lymphocytes respond to foreign substances called
antigens and differentiate into plasma cells that
produce antibodies. Antibodies attach to and
inactivate the antigens.
■ T lymphocytes directly attack microbes.
22. Copyright 2010, John Wiley & Sons, Inc.
White Blood Cell Functions
■ Major histocompatibility (MHC) antigens
❑ Proteins protruding from plasma membrane of
WBCs (and most other body cells)
❑ Called “self-identity markers”
■ Unique for each person (except for identical twins)
■ An incompatible tissue or organ transplant is rejected
due to difference in donor and recipient MHC antigens
■ MHC antigens are used to “type tissues” to check for
compatibility and reduce risk of rejection
23. Copyright 2010, John Wiley & Sons, Inc.
WBC Life Span
■ WBCs: 5000-10,000 WBCs/µl blood
■ RBCs outnumber WBCs about 700:1
■ Life span: typically a few hours to days
■ Abnormal WBC counts
❑ Leukocytosis: high WBC count in response to
infection, exercise, surgery
❑ Leukopenia: low WBC count
■ Differential WBC count: measures % of
WBCs made up of each of the 5 types
24. Copyright 2010, John Wiley & Sons, Inc.
Platelets
■ Myeloid stem cells megakaryocytes
2000–3000 fragments = platelets
■ Normal count: 150,000-400,000/µl blood
■ Functions
❑ Plug damaged blood vessels
❑ Promote blood clotting
■ Life span 5–9 days
25. Copyright 2010, John Wiley & Sons, Inc.
Hemostasis: “Blood Standing Still”
Sequence of events to avoid hemorrhage
1. Vascular spasm
❑ Response to damage
❑ Quick reduction of blood loss
2. Platelet plug formation
❑ Platelets become sticky when contact damaged
vessel wall
3. Blood clotting (coagulation)
❑ Series of chemical reactions involving clotting
factors
26. Copyright 2010, John Wiley & Sons, Inc.
Blood Clotting (Coagulation)
■ Extrinsic pathway
❑ Tissue factor(TF) from damaged cells 1 2 3
■ Intrinsic Pathway
❑ Materials “intrinsic” to blood 1 2 3
■ Common pathway: 3 major steps
1. Prothrombinase
2. Prothrombin thrombin
3. Fibrinogen fibrin clot
■ Ca++
plays important role in many steps
27. Copyright 2010, John Wiley & Sons, Inc.
Clot Retraction and Vessel Repair
■ Clot plugs ruptured area
■ Gradually contracts (retraction)
❑ Pulls sides of wound together
■ Repair
❑ Fibroblasts replace connective tissue
❑ Epithelial cells repair lining
28. Copyright 2010, John Wiley & Sons, Inc.
Hemostatic Control Mechanisms
■ Fibrinolysis: breakdown of clots by plasmin
❑ Inactivated plasminogen
❑ Activated (by tPA) plasmin
■ Inappropriate (unneeded) clots
❑ Clots can be triggered by roughness on vessel
wall = thrombosis
❑ Loose (on-the-move) clot = embolism
■ Anticoagulants: decrease clot formation
❑ Heparin
❑ Warfarin (Coumadin)
29. Copyright 2010, John Wiley & Sons, Inc.
Tissue
trauma
Tissu
e
factor
(TF)
Blood
trauma
Damaged
endothelial
cells
expose
collagen
fibers
(a) Extrinsic
pathway
(b) Intrinsic
pathway
Activated
XII
Ca2
+
Damage
d
platelets
Ca2
+
Platelet
phospholipid
s
Activated
X
Activate
d
platelets
Activated
X
PROTHROMBINASE
Ca2
+
V
Ca2
+
V
1
Tissue
trauma
Tissu
e
factor
(TF)
Blood
trauma
Damaged
endothelial
cells
expose
collagen
fibers
(a) Extrinsic
pathway
(b) Intrinsic
pathway
Activated
XII
Ca2
+
Damage
d
platelets
Ca2
+
Platelet
phospholipid
s
Activated
X
Activate
d
platelets
Activated
X
PROTHROMBINASE
Ca2
+
V
Ca2
+
Prothrombin
(II)
Ca2
+
THROMBIN
(c) Common
pathway
V
1
2
+
+
Tissue
trauma
Tissu
e
factor
(TF)
Blood
trauma
Damaged
endothelial
cells
expose
collagen
fibers
(a) Extrinsic
pathway
(b) Intrinsic
pathway
Activated
XII
Ca2
+
Damage
d
platelets
Ca2
+
Platelet
phospholipid
s
Activated
X
Activate
d
platelets
Activated
X
PROTHROMBINASE
Ca2
+
V
Ca2
+
Prothrombin
(II)
Ca2
+
THROMBIN
Ca2
+
Loose
fibrin
threads
STRENGTHENED
FIBRIN THREADS
Activated
XIII
Fibrinoge
n
(I)
XII
I
(c) Common
pathway
V
1
2
3
+
+
Stages of
Clotting
30. Copyright 2010, John Wiley & Sons, Inc.
Blood Groups and Blood Types
■ RBCs have antigens (agglutinogens) on their
surfaces
■ Each blood group consists of two or more
different blood types
❑ There are > 24 blood groups
❑ Two examples:
■ ABO group has types A, B, AB, O
■ Rh group has type Rh positive (Rh+
), Rh negative (Rh–
)
■ Blood types in each person are determined
by genetics
31. Copyright 2010, John Wiley & Sons, Inc.
ABO Group
■ Two types of antigens on RBCs: A or B
❑ Type A has only A antigen
❑ Type B has only B antigen
❑ Type AB has both A and B antigens
❑ Type O has neither A nor B antigen
■ Most common types in US: type O and A
■ Typically blood has antibodies in plasma
❑ These can react with antigens
❑ Two types: anti-A antibody or anti-B antibody
❑ Blood lacks antibodies against own antigens
■ Type A blood has anti-B antibodies (not anti-A)
■ Type AB blood has neither anti-A nor anti-B antibodies
33. Copyright 2010, John Wiley & Sons, Inc.
Rh Blood Group
■ Name Rh: antigen found in rhesus monkey
■ Rh blood types
❑ If RBCs have Rh antigen: Rh+
❑ If RBCs lack Rh antigen: Rh–
■ Rh+
blood type in 85-100% of U.S. population
■ Normally neither Rh+
nor Rh–
has anti-Rh
antibodies
■ Antibodies develop in Rh-
persons after first
exposure to Rh+
blood in transfusion (or
pregnancy hemolytic disease of newborn)
34. Copyright 2010, John Wiley & Sons, Inc.
Transfusions
■ If mismatched blood (“wrong blood type”)
given, antibodies bind to antigens on RBCs
hemolyze RBCs
■ Type AB called “universal recipients”
because have no anti-A or anti-B antibodies
so can receive any ABO type blood
■ Type O called “universal donors” because
have neither A nor B antigen on RBCs so can
donate to any ABO type
❑ Misleading because of many other blood groups
that must be matched
35. Copyright 2010, John Wiley & Sons, Inc.
End of Chapter 14
■ Copyright 2010 John Wiley & Sons, Inc.
All rights reserved. Reproduction or translation of
this work beyond that permitted in section 117 of the
1976 United States Copyright Act without express
permission of the copyright owner is unlawful.
Request for further information should be addressed
to the Permission Department, John Wiley & Sons,
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