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PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
17
Blood
Modified by:
Olga E. Vazquez
Copyright © 2010 Pearson Education, Inc.
Cardiovascular System
• Cardio = heart
• Vascular = blood vessels
• Consists of three interrelated components:
• Blood
• Heart
• Blood vessels
• We will now examine the blood.
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Topics Discussed Today
• Blood as connective tissue
• Physical characteristics and volume of blood
• Functions of blood
• Blood components
• Plasma
• Formed elements
• Hematopoiesis
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Blood
• Blood is unique from person to person
• Health care professionals routinely examine
and analyze its differences through various
blood tests to determine the causes of
different diseases.
• Hematology = study of blood
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Blood: An Overview
• Blood is the only fluid tissue in the
body.
• Even though it might seem like a
homogeneous liquid, the microscope
reveals 2 components:
• Cellular component
• Liquid component
• What type of tissue is blood classified
as?
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Blood: An Overview
• Blood is a specialized type of connective
tissue in which living blood cells, the formed
elements (cells), are suspended in a nonliving
fluid matrix called plasma.
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Blood: An Overview
• Blood cells carry oxygen and nutrients to our body’s
tissues, and remove Carbon Dioxide and other
wastes, and take them to places to be removed from
the body.
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Physical Characteristics and Volume
• Total blood volume: 8%
of body weight
• Average volume in
healthy males:
• 5-6 L (~ 1.5 gallons)
• Average volume in
healthy females:
• 4-5 L (1.05 to 1.32
gallons)
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Physical Characteristics and Volume
• Blood is more dense than water and about
5 times more viscous. Why?
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Functions
• Blood performs a number of functions, all
concerned in one way or another with:
• Distribution
• Regulation
• Protection
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Functions
• There are six functions:
1. Transportation
• O2 lungs → cells
• CO2 cells → lungs
• Nutrients → cells
• waste from cells → kidneys (excretion!)
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Functions
2. Defense
• White blood cells – fight disease
• blood proteins – antibodies (identification)
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Functions
3. Temperature regulation - absorbs and distribute
heat throughout body and skin
4. Prevents loss of blood – blood clots
5. Hormone movement – endocrine gland → cells
6. Regulates pH (our acid/base balance in our
bodies) – through buffers
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Components of Blood
• If a sample of blood is spun in a centrifuge, the
heavier formed elements are packed down by
centrifugal force and the less dense plasma
remains at the top.
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Components
• Bottom – erythrocytes
(what are they?)
• Erythro = red
• Buffy coat – whitish layer
present at the erythrocyteplasma junction
• Contains platelets and
leukocytes (white blood
cells)
• Plasma
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Plasma
• Makes up 55% of blood
• Although is made up of
about 90% water,
plasma contains over
100 different dissolved
solutes including gases,
hormones, waste, etc.
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Plasma
• Contains proteins
• Contains electrolytes
• Contains wastes to be taken away
• Contains water
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Components of Whole Blood
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Formed Elements
• The formed elements are
present in the buffy coat
and the bottom red layer.
• In other words the
formed elements are the
red blood cells, white
blood cells, and platelets
(platelets help form clots)
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Components of Whole Blood
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Figure 17.2
Formed Elements
• These cells have unusual features.
• Two of the three are not even true cells. Why?
• RBC’s have no nuclei or organelles, and
platelets are cell fragments. Only leukocytes are
true cells
• Most of the formed elements survive in the
bloodstream for only a few days.
• Most blood cells do not divide.
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Formed Elements
• Erythrocytes normally
constitute 45% of the total
volume of blood.
• This percentage is known
as hematocrit (“blood
fraction”).
• In males and females, this
percentage might differ:
• males: 47% ± 5%
• females: 42% ± 5%
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Formed Elements
• RBC or erythrocytes are involved in gas
transport
• Carry O2
• Carry 20% of CO2
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Formed Elements
• WBC or leukocytes have
many specialized
functions. Together with
platelets, leukocytes
contribute less than 1% of
blood volume.
• Immunity
• T cells, B cells,
neutrophils, macrophages
• Most abundant –
neutrophils
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Formed Elements
• Platelets
• Cell fragments
• Encourage clot formation
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Formed Elements Formation
• Hematopoiesis (hemato = blood, poiesis = to
make)
• Process in which formed elements of the blood
develop
• Erythropoiesis
• Leukopoiesis
• Before birth it occurs
• Yolk sac
• Later in the liver, spleen, thymus and lymph nodes
• Last 3 months of gestation in the red bone marrow
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Hematopoiesis
• During childhood (up to 5
years) occurs in the
epiphysis of almost all long
bones.
• In adults it occurs also in flat
and irregular bones such as
the skull, sternum, hip bone,
ribs, and vertebra.
• Formed element production
in adult’s long bones occurs
in the humerus and femur.
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Checking Understanding
• Explain why blood is classified as a connective tissue
• What is the average blood volume in human adult?
• What are the two components of the blood?
• Why blood is more viscous than water?
• List three major functions of blood and provide an example of
each.
• Name the formed elements. Why are they elements instead of
cells?
• What is the hematocrit? What is the normal value?
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Red Blood Cells
• Erythrocytes
• Erythro =
• Cyte =
• The erythrocyte is an excellent example of
complementarity of structure and function.
• Each structural characteristic contributes to its
gas transport functions.
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Structural Characterstics
• Its small size and
biconcave shape
provides 30% more
surface area than other
spherical cells. Why is
this important?
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Structural Characteristics
• No nucleus (anucleate) or
organelles
• The red blood cell carries a
protein called “hemoglobin”
that carries the oxygen to our
body parts.
• Hemoglobin is made partly
with iron.
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Structural Characteristics
• Major function of RBC is to
transport hemoglobin.
• Erythrocytes are over 97%
hemoglobin. This is why RBC
could be called “bags” of
hemoglobin.
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Hemoglobin
• It’s the protein that makes RBC red.
• Binds easily and reversibly to oxygen
• Oxygen moves in the blood bound to
hemoglobin
• Normal values of hemoglobin
• 14-20 g/100ml in infants
• 13-18 g/100ml in adult males
• 12-16 g/100ml in adult females
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Hemoglobin
• A single RBC contains about 250 million
hemoglobin molecules.
• So, each RBC can hold about 1 billion
molecules of O2.
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Erythropoiesis
• Erythropoiesis needs to be controlled so there is
a balance between RBC production and
destruction.
• New cells are made at a rate of more than 2
million per second in healthy people.
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Erythropoietin
• Hormone effects:
• Hormones produced in the kidney and liver
• Stimulates red bone marrow to increase rate of
cells
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Homeostasis: Normal blood oxygen levels
1 Stimulus:
Hypoxia (low blood
O2- carrying ability)
due to
• Decreased
RBC count
• Decreased amount
of hemoglobin
• Decreased
availability of O2
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Figure 17.6, step 1
Homeostasis: Normal blood oxygen levels
1 Stimulus:
Hypoxia (low blood
O2- carrying ability)
due to
• Decreased
RBC count
• Decreased amount
of hemoglobin
• Decreased
availability of O2
2 Kidney (and liver to
a smaller extent)
releases
erythropoietin.
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Figure 17.6, step 2
Homeostasis: Normal blood oxygen levels
1 Stimulus:
Hypoxia (low blood
O2- carrying ability)
due to
• Decreased
RBC count
• Decreased amount
of hemoglobin
• Decreased
availability of O2
2 Kidney (and liver to
3 Erythropoietin
a smaller extent)
releases
erythropoietin.
stimulates red
bone marrow.
Copyright © 2010 Pearson Education, Inc.
Figure 17.6, step 3
Homeostasis: Normal blood oxygen levels
1 Stimulus:
Hypoxia (low blood
O2- carrying ability)
due to
• Decreased
RBC count
• Decreased amount
of hemoglobin
• Decreased
availability of O2
4 Enhanced
erythropoiesis
increases RBC
count.
2 Kidney (and liver to
3 Erythropoietin
a smaller extent)
releases
erythropoietin.
stimulates red
bone marrow.
Copyright © 2010 Pearson Education, Inc.
Figure 17.6, step 4
Homeostasis: Normal blood oxygen levels
1 Stimulus:
Hypoxia (low blood
O2- carrying ability)
due to
• Decreased
RBC count
• Decreased amount
of hemoglobin
• Decreased
availability of O2
5 O2- carrying
ability of blood
increases.
4 Enhanced
erythropoiesis
increases RBC
count.
2 Kidney (and liver to
3 Erythropoietin
a smaller extent)
releases
erythropoietin.
stimulates red
bone marrow.
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Figure 17.6, step 5
Analyzing
• How might your hematocrit change if you
move from a town at sea level to a high
mountain village?
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Destruction of Erythrocytes
• Red blood cells have a useful life span of 100
to 120 days, after which they become trapped
and fragment in smaller circulatory channels,
particularly in those of the spleen.
• In the red pulp of the spleen, RBC rupture when
they try to squeeze through because of their
fragile old membrane.
• For this reason, the spleen is sometimes called
the “red blood cell graveyard
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Anemia
• Any decrease in blood’s oxygen-carrying
capacity is known as anemia.
• Causes:
• Insufficient number of RBC
• Low hemoglobin content
• Abnormal hemoglobin
• One of the major effects of anemia is the greatly
increased work load on the heart.
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Human Blood Groups
• RBC’s have antigens (identifiers) on them.
• The presence or absence of these antigens
tell us what blood type we have.
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Markers on RBC
• If there are no blood type
antigens, you have type O
blood.
• If you have B type antigens,
you have type B blood.
• If you have A type antigens,
you have A type blood.
• What about people with type
AB blood?
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People that carry
the “D” antigen
are Rh +. If they
do not have the
antigen, they are
Rh-
ABO Markers
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Rh Factor
• There are 45 different types of Rh agglutinogens.
• Three of which (C, D, and E) are common
• About 85% of Americans are Rh positive, which
means they carry the D antigen.
• Presence of the Rh agglutinogens on RBCs is
indicated as Rh+
• As a rule, a person’s ABO and Rh blood groups
are reported together, for example, O+, A-, and
so on.
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Rh Factor and Pregnancy
• Rho GAM
• Injection of anti-Rh antibodies given soon after
every delivery, miscarriage, abortion-binds
• Inactivates fetal Rh antigens so mother’s
immune system doesn’t respond
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Checking Your Understanding
• What is the main function of RBC?
• What organ is the red blood cell graveyard?
• Mrs. D has type A blood and is Rh+. So, she has A+
blood. What antigens (ID markers) are carried on her
blood?
• Mrs. D’s husband has type A- blood. What does this
mean?
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