The Cardiovascular System:
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Blood
Unit 1
Chapter 14
• Transportation-hormones, gasses,
nutrients, ions, heat
• Regulation- pH, temperature, water
balance in cells
• Protection- clotting, white cells
interferons, complement
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Unit 1
Function
• Connective tissue-Two parts
• Plasma = soluble materials (~55%)
• Formed Elements = cells (~45%)
• Percent occupied by red blood cells
(RBC) = hematocrit (Hct)
• White blood cells (WBC) ~1%
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Composition
Figure 14.1a
Figure 14.1b
• ~91% water, 7% proteins, 1.5 % other
solutes
• Proteins: Albumin (54%)- osmosis and
carriers;
• Globulins (38%)- antibodies
• Fibrinogen (7%)- clotting
• Other: Electrolytes , nutrients, gases,
hormones, vitamins & waste products
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Plasma
Formed Elements
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I. Red Blood Cells
II. White blood cells
A. granular Leukocytes
1. Neutrophils
2. Eosinophils
3. Basophils
1. T & B lymphocytes & natural Killer cells
2. monocytes
III Platelets
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B. Agranular leukocytes
Formation of Blood Cells
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• Called hemopoiesis
• Just before birth and throughout life
occurs in red bone marrow
• Contains pluripotent stem cells
• In response to specific hormones
these develop through a series of
changes to form all of the blood cells
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Figure 14.2a
Figure 14.2b
Erythrocytes (RBCs)
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• Hemoglobin package- carries oxygen
• Male has ~ 5.4 million cells/µl; Female
has ~4.8 million
• membrane, no nucleus, flexible structure
• use glucose for ATP production to
maintain ionic composition
No mitochondria
• Wear out fast- live ~120 days
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Also carries some CO2
RBC Cycling
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• cleared by macrophages (liver &
Spleen)
• Fe- recycled in bone marrow
• Heme bilirubin and excreted (bile)
• Globin A.A. recycled.
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Carried in blood on transferrin
Figure 14.3
RBC Synthesis
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• called erythropoiesis
• From stem cells: hemocytoblasts
• Released as reticulocytes
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Production & destruction is balanced
Low O2 delivery (hypoxia) 
erythropoietin release (EPO) from kidney
Stimulates erythropoiesis
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Mature to erythrocytes in 1-2 days
Figure 14.4
White Blood Cells
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Neutrophil- first responders
Monocytes macrophages (big eaters)
Eosinophil- phagocitize antibody-antigen complexes
Involved in suppressing allergic responses
Basophil- intensify allergic reactions
• Immune response:
T-cells, B-cells& natural killer (NK) cells
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• Defenses: phagocytes, antibody
production and antibacterial action
• Phagocytes:
WBC Life Span
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5000-10,00 WBC /µl blood
Limited number of bacteria can be eaten
Life span is a few days
During active infection may be hours
Leukocytosis= increased WBC
numbers response to stresses
• Leukopenia = decreased WBC numbers
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• Myeloid stem cells 
megakaryocytes  2000 -3000
fragments = platelets
• Plug damaged blood vessels
• Promote blood clotting
• Life span 5-9 days
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Platelets
Hemostasis
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• Hemostasis = stationary blood
• 1. Vascular reactions (spasm)
Response to damage
Quick reduction of blood loss
• 2. platelet plug formation
• 3. blood clotting (coagulation)
Series of chemical reactions involving clotting
factors
• Clotting in unbroken vessel=
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Become sticky when contact damaged vessel
wall
Coagulation
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• Extrinsic pathway common steps
tissue factor(TF) from damaged cells
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• Intrinsic Pathway  common steps
• 1. prothrombinase which causes
• 2. prothrombin thrombin causes
• 3. fibrinogen  fibrin  clot
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Materials “intrinsic” to blood 1
• Clot pugs ruptured area
• Gradually contracts (retraction)
• Pulls sides of wound together
• Fibroblasts replace connective tissue
• epithelial cells repair lining
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Clot Retraction & Vessel Repair
• Fibrinolysis: dissolving of clot by
activated plasmin enclosed in clot
• Clots can be triggered by roughness
on vessel wall = thrombosis
• Loose clot = embolus and can block
a small vessel = embolism
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Control Mechanisms
Figure 14.5
Blood Types
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> 24 blood groups and > 100 different
antigens
• We will deal with ABO and Rh groups
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• Surface antigens- react with
antibodies
• Divided into groups based on
antigens
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Two antigens = A & B
If have only A –type A
If have only B –type B
If neither then Type O
Blood usually has antibodies that can
react with antigens
e.g. anti-A antibody or anti-B antibody
• You don’t react with your own antigens
Thus: type A has anti-B and vice versa
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ABO Group
Figure 14.6
• Antigen discovered in rhesus monkey
• If have antigen- Rh+
• Normally don’t have antibodies
• antibodies develop after the first
exposure from transfusion
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Rh Blood Group
• If mismatched blood given antibodies bind
to it and hemolyze cells
• Type AB has no AB antibodies so can
receive any ABO type blood called
Universal recipients
• Type O have neither antigen so can
donate to any other ABO type called
Universal donors
• Misleading because of many other
blood groups that must be matched
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Transfusions