The Cardiovascular System:
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Blood
Unit 1
Chapter 14
Function
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• 3 components of the cardiovascular
system = blood, heart, blood vessels
• Function of CV system = transports
substances to and from body cells
• Hematology = branch of science that
deals with study of blood, bloodforming tissues and disorders
associated with them
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• Is a type of connective tissue
• Transportation- gasses (O2 & CO2),
nutrients (GI tract), heat & waste,
hormones (endocrine system)
• Regulation- pH, temperature, water
balance in cells
• Protection- loss of blood via clotting,
WBC vs. disease; production of
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Functions of Blood
•5
1.
2.
3.
4.
5.
facts about blood
Blood is thicker than water
Temp is 38° C
Slightly alkaline 7.35 – 7.45
8% of total body weight
Volume = males – 5-6 liters
females – 4-5 liters
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Components
• Connective tissue-Two parts
• Plasma = straw-colored liquid with
dissolved materials (~55%)
• Formed Elements = cells and cells
fragments (~45%) 99% of the
formed elements are RBCs
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Composition
Composition
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• Buffy coat – part made up by white
blood cells (WBC) and plateletes
~1%
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• hematocrit (Hct) = Percent of blood
volume occupied by red blood cells
(RBC)
Figure 14.1a
Figure 14.1b
• ~91% water, 7% proteins, 1.5 % other
solutes
• Proteins: Albumin (54%)- maintains
osmotic pressure;
• Globulins (38%)- antibodies for defense
• Fibrinogen (7%)- clotting
• Other solutes in plasma: 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
• Hemopoiesis – production of formed
elements
• 3 months 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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Formation of Red Blood
Cells
Formation of Red Blood
Cells
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• Bone marrow contains pluripotent
stem cells – cells that can develop into
many different types of cells
• In response to specific hormones
these develop into myeloid stem cells
(RBC, platelets, and some WBC) and
lymphoid stem cells (T and B
lymphocytes)
Figure 14.2a
Figure 14.2b
Red Blood Cells
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• AKA = Erythrocytes
• Contains - hemoglobin proteincarries oxygen
• Male has ~ 5.4 million cells/µl;
Female has ~4.8 million
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Also carries some CO2
Erythrocytes (RBCs)
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• Production rate = 2 million/sec
• Contain no nucleus & other
organelles
• Consists of membrane, cytosol,
hemoglobin
• Biconcave shape provides for greater
surface area for the diffusion of gas
molecules into/out of a RBC
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• Wear out fast- live ~120 days due to
wear and tear as they squeeze
through capillaries
• Worn out and ruptured cells are
cleared by macrophages (liver spleen,
red bone marrow)
• Fe- recycled in bone marrow
Carried in blood on transferrin – plasma
protein acts as a transporter for iron
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RBC Cycling
• biliverdin  bilirubin – what the
non-iron portion of heme is
converted into and excreted (bile)
• Urobilinogen and stercobilin – by
products of bilirubin; some absorbed
in large intestine; ultimately excreted
in urine or feces
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RBC Cycling
Figure 14.3
RBC Production
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• called erythropoiesis
• Released as reticulocytes (almost
a RBC)
• Production & destruction is
balanced
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Mature to erythrocytes in 1-2 days
• If O2 carrying capacity falls, RBC
productions is inc. by a negative
feedback loop
• Low O2 delivery (hypoxia) 
• erythropoietin (EPO)- kidney
hormone  stimulates
erythropoiesis
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RBC Synthesis
• Cyanosis – life threatening
condition caused by prolonged
hypoxia; bluish-purple skin
coloration
• Anemia – reduced O2 carrying
capacity – reduced # of RBC or ↓
amount of hemoglobin in blood;
pale skin
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RBC Synthesis
Figure 14.4
• aka = leukocytes
• Classified as either 1. granular which
contains a chemical filled cytoplasmic
granule/vesicle (neutrophils,
eosinophils, basophils) or 2. agranular
(lymphocytes, monocytes)
• Function in defense: phagocytosis or
antibody production
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White Blood Cells
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White Blood Cells
• Phagocytes:
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Neutrophil- first responders; release lysozomes that
destroy bacteria
Monocytes slower response; become wandering
macrophages (big eaters compared to neutrophils)
Eosinophil- work in interstitial fluid; Involved in
suppressing allergic responses; phagocitize
antibody-antigen complexes and are effective
against some parasitic worms
Basophil- intensify allergic reactions
White Blood Cells
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• Phagocytes:
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a. Neutrophil- first responders; release
lysozomes that destroy bacteria
b. Monocytes slower response;
become wandering macrophages (big
eaters compared to neutrophils)
White Blood Cells
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d. Basophil- release heparin, histamines,
serotonin; intensify allergic reactions
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• Phagocytes:
c. Eosinophil- phagocitize
antibody-antigen complexes
involved in suppressing allergic
responses
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White Blood Cells
• Producing antibodies (Immune
response):
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B-cells – plasma cells – produce antibodies
to help destroy bacteria/inactivate toxins
T-cells – attack viruses, fungi, cancer cells,
transplanted cells, bacterial cells
Natural killer (NK) cells – attack infectious
microbes and some types of tumor cells
White Blood Cells
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• Major histocompatibility (MHC)
antigens – proteins on the surface of
a cells that act as “cell identity
markers” that are unique for each
person; used to type tissue for
transplants
WBC Life Span
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• Life span is a few days normally; a
few hour during an active infection;
some B and T cells live for years
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• Number of RBC vs. WBC is 700:1;
5000-10,000 WBC /µl blood
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WBC Life Span
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• Leukocytosis= normal increase in
WBC #’s  response to stresses;
indicates inflammtion/infection
• Differential white blood cell count is
the measure of the different types of
WBC per 100 WBC (helps in diagnosis)
• Leukopenia = abnormally low WBC
numbers; never good; radiation,
shock, some chemotherapeutic agents
Platelets
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• Myeloid stem cells  megakaryoblasts 
megakaryocytes  2000 -3000
fragments = platelets
• Plug damaged blood vessels
• Promote blood clotting
• Life span 5-9 days
Hemostasis
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• Hemorrhage - loss of large amounts
of blood
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• Hemostasis = stationary blood – a
series of responses that stop bleeding
when blood vessels are injured
1. Vascular reactions (spasm)
2. platelet plug formation
3. blood clotting (coagulation)
• 1. Vascular spasm – contraction of
smooth muscle in the walls of a
damaged blood vessel; effective for
several minutes to several hours;
platelets at the site release chemicals
to enhance vasoconstriction
maintaining vascular spasm
Quick reduction of blood loss
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Hemostasis
Hemostasis
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• 2. platelet plug formation – platelets
stick to parts of a damaged blood
vessel; they release chemcials to
make other platelets sticky;
eventually forms a platelet plug
Hemostasis
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• 3. blood clotting –when blood is
withdrawn it separates into serum
and a gel called fibrin (protein fibers
that make up a clots)
• Clotting (coagulation) –process of
clot formation; series of chemical
reactions involving clotting factors
• Thrombosis – clotting in an
unbroken blood vessel
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• 1. prothrombinase is formed
• 2. prothrombinase converts
prothrombin (a protein)  thrombin
(an enzyme)
• 3. thrombin converts fibrinogen
(another protein)  fibrin (fibers
that form the threads of a clot)
clot
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3 Stages of Clotting
Prothrombinase Formation
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• Extrinsic pathway happens
quickly;
• Intrinsic Pathway  takes several
minutes
Materials “intrinsic” to blood make
prothrombinase
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tissue factor(TF) from damaged cells
makes prothrombinase
• Clot retraction- consolidation or
tightening of the fibrin clot
• As the clot retracts damaged edges
of blood vessels pull closer together
• Permanent repairs take place when
fibroblasts form connective tissue
and endothelial cells repair the
vessel lining
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Clot Retraction & Vessel Repair
Control Mechanisms
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• Fibrinolysis: dissolving of unnecessary
clots by activated plasmin which
digests fibrin threads in a clot
• Clots can be triggered by
1. Roughness on vessel wall as a
result of atherosclerosis, trauma,
infection
2. If the flow of blood becomes too
slow clotting factors accumulate
enough to trigger a clot
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Clotting in Blood Vessels
• Thrombosis - clotting in an unbroken
vessel (thrombus = clot)
• Blood clot, air bubble, or fat from a
broken bone transported by blood=
embolus and can block a small blood
vessel
• Pulmonary embolism – blockage of
blood vessel in the lungs
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Control Mechanisms
Figure 14.5
• Agglutinogens – antigens composed
of glycolipids/proteins on the surface
of RBC
• Blood groups are categorized based
on the presence or absence of
various antigens
• >24 blood groups and >100 antigens
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Blood Group and Types
• We will deal with ABO and Rh groups
• ABO blood group has two antigens A
and B
• Your blood type is determined by
which you have (if you have the A
antigen you have blood type A; AB
blood has both the A and B antigen;
O has no antigen)
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Blood Types
ABO Group
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• Blood usually has antibodies or
agglutinins that can react with
antigens
e.g. anti-A antibody or anti-B antibody
Thus: type A has anti-B and vice versa
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• You don’t react with your own
antigens
Figure 14.6
• The Rh blood group is named after
the rhesus monkey where the Rh
antigen was discovered
• If have antigen you are Rh+
• Normally we don’t have anti-Rh
antibodies they develop after the
first exposure from transfusion
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Rh Blood Group
• Transfusion – transfer of whole
blood or blood components (plasma)
• If mismatched blood is given
antibodies in the recipient's blood
bind to the antigens on the donated
RBC and causes hemolysis (rupture
of RBC)
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Transfusions
• Universal recipients - Type AB has no
AB antibodies so can receive any ABO type
blood
• Universal donors - Type O have neither
antigen so can donate to any other ABO
type
• Misleading because of many other
blood groups that must be matched
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Transfusions