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Human Anatomy
McKinley & O'Loughlin
Chapter 18
Blood
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Blood-Heart
Heart-vessels
Vessels-LymphLec quiz 4
Lymph-Resp
Exam 4: Cardio-Resp
21-2
Blood
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Why is Blood Red?
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Average adult has ___pints of blood?
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Blood Types: U.S. Average
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A = 34%
B = 9%
AB = 3%
a- 6%
b- 9%
ab- 1%
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Blood
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Blood is a Connective Tissue Because……
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it contains cells,
a liquid ground substance (called plasma),
dissolved protein fibers.
Blood is also:
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four times more viscous (or thicker) than water.
Temperature of blood is about 1°C higher than measured body temperature.
Can be broken down into its liquid and cellular components by a machine
called a centrifuge.
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blood is withdrawn from a vein and collected in a centrifuge tube
tube is placed into the centrifuge, which then spins it in a circular
motion for several minutes
rotational movement separates the blood into
 Liquid & Cellular components
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Components of Blood(3)
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1. Erythrocytes (or red blood cells)
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2. Buffy coat
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form the lower layer of the centrifuged blood
typically make up about 44% of a blood sample
makes up the middle layer
thin, slightly gray-white layer composed of cells called
leukocytes (or white blood cells) and cell fragments called
platelets
forms less than 1% of a blood sample
3. Plasma
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straw-colored liquid that rises to the top
generally makes up about 55% of blood
21-6
Components of Blood
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Erythrocytes and the components of the buffy coat are
called the formed elements.
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not “cells,” merely fragments broken off from a larger cell
Formed elements and the liquid plasma compose whole
blood.
So…..
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Formed Elements = RBC’s + buffy coat(WBC’s + platelets)
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Formed elements + Plasma = whole blood
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Functions of Blood
1. Transportation
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Transports numerous elements and compounds
throughout the body.
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erythrocytes carry oxygen from the lungs to body cells and
then transport carbon dioxide from the cells back to the
lungs for expulsion from the body
blood plasma
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transports nutrients that have been absorbed from the GI tract
hormones secreted by the endocrine organs to their target cells
plasma
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carries waste products from the cells to organs such as the
kidneys, where these waste products are removed
21-9
Functions of Blood
2. Regulation of Body Temp.
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Regulates body temperature.
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plasma absorbs and distributes heat throughout
the body
for cooling the blood vessels in the dermis
dilate and dissipate the excess heat through the
integument
when the body needs to conserve heat, the
dermal blood vessels constrict, and the warm
blood is shunted to deeper blood vessels in the
body
21-10
Functions of Blood
3. Regulation of pH Levels
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Blood plasma pH is continuously regulated at a
value of 7.4 the pH level required for normal
cellular functioning.
 pH is a measure of how alkaline or acidic a fluid is.
 Neutral pH is measured at exactly 7.
 Acidic fluids ( orange juice) are between 0 and
7.
 Alkaline fluids ( milk) are between 7 and 14.
 Blood plasma contains compounds and ions that
may be distributed to the fluid among tissues
(interstitial fluid) to help maintain normal tissue
21-11
pH.
Functions of Blood
4. Maintenance of Fluid Levels
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Maintains normal fluid levels in the
cardiovascular system.
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IF… too much fluid is absorbed in the blood,
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Prevents fluid loss.
Constant exchange of fluid between the blood plasma and
the interstitial fluid.
High Blood Pressure results
If too much fluid escapes the bloodstream and enters
the tissues, may drop to unhealthy low levels, and the
tissues swell with excess fluid.
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Blood Pressure Drops
21-12
Functions of Blood –
5. Protection
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Leukocytes (white blood cells) help guard against
infection
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Plasma
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mounting an immune response if a pathogen or an antigen
is found.
transports antibodies, which are molecules that can
immobilize antigens until a leukocyte can completely kill or
remove the antigen.
Platelets and blood proteins
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protect the body against blood loss by forming blood clots
on damaged vessels.
21-13
Components of Plasma
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Complex mixture of water, proteins, and other
solutes.
When the proteins are moved from plasma, the
remaining fluid is termed serum.
Water makes up about 92% of plasma’s total
volume.
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water facilitates the transport of materials in the plasma
21-14
Plasma Proteins (4)
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The next most abundant materials in plasma
are the plasma proteins.
Make up about 7% of the plasma.
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6 and 8 grams of protein in a volume of 100
milliliters of blood (referred to as g/dl)
The plasma proteins include:
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albumins
globulins
fibrinogen
regulatory proteins
21-15
Plasma Proteins
1. Albumins
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Smallest and most abundant of the plasma
proteins.
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make up approximately 58% of total plasma proteins
Regulate water movement between the blood
and interstitial fluid.
Albumins act as transport proteins that carry ions,
hormones, and some lipids in the blood.
21-16
Plasma Proteins
2. Globulins
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Second largest group of plasma proteins,
forming about 37% of all plasma proteins.
Smaller alpha-globulins and the larger beta-globulins
primarily bind, support, and protect certain waterinsoluble or hydrophobic molecules, hormones, and
ions.
Also called immunoglobulins or antibodies.
Produced by some of our defense cells to protect the
body against pathogens that may cause disease.
21-17
Plasma Proteins
3. Fibrinogen
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Makes up about 4% of all plasma proteins.
Responsible for blood clot formation.
Following trauma to the walls of blood vessels,
fibrinogen is converted into long, insoluble strands of
fibrin, which is the essence of a blood clot.
21-18
Plasma Proteins
4. Regulatory Proteins
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Form a very minor class of plasma proteins.
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<1% of total plasma proteins
Include enzymes to accelerate chemical reactions in
the blood and hormones being transported
throughout the body to target cells.
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Formed Elements in the Blood
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Erythrocytes
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Leukocytes
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make up more than 99% of formed elements
primary function is to transport respiratory gases in the
blood
make up less than .01% of formed elements
contribute to defending the body against pathogens
Platelets
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make up less than 1% of formed elements and
help with blood clotting
21-20
Hematocrit
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Percentage of erythrocytes in the blood.
Values vary slightly and are dependent on age and sex.
Adult males
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Females
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range between 42% and 56% .
range from 38% to 46%.
Altitude can affect the hematocrit.
 body compensates by making more erythrocytes
 more erythrocytes in the blood can carry more oxygen to
the tissues
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Erythrocytes
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Mature erythrocytes lack nuclei.
 Lack of nuclei enables them to carry respiratory
gases more efficiently
The “job” of these erythrocytes is to Transport
oxygen and carbon dioxide to and from the tissues
and the lungs.
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Hemoglobin in Erythrocytes
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Every erythrocyte is filled with approximately 280
million molecules of a red-pigmented protein called
hemoglobin.
Transports oxygen and carbon dioxide, and is
responsible for the characteristic bright red color of
arterial blood.
Hemoglobin that contains no oxygen has a deep red
color that is perceived as blue because the blood
within these veins is observed through the layers of
the skin and the subcutaneous tissue.
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Antibodies
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An antibody interacts with a specific antigen.
The ABO blood group has both anti-A and anti-B
antibodies that react with the surface antigen A and
the surface antigen B, respectively.
The antibodies in your blood plasma do not
recognize the surface antigens on your
erythrocytes.
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Leukocytes
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Leukocytes are true “cells” because….
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they contain a nucleus and cellular organelles.
Leukocytes help initiate an immune response and
defend the body against invading pathogens.
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Leukocytes also differ from erythrocytes in that they are
about 1.5 to 3 times larger, and they do not contain
hemoglobin.
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Leukocytes
Granulocytes (3)
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1. Neutrophil
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2. Eosinophils have reddish, or pink-orange granules in their
cytoplasm.
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60–70% of the total number of leukocytes
constitute about 2–4% of the total number of leukocytes
nucleus usually has two lobes, which are connected by a thin
strand
3. Basophils are
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1.5 times larger than erythrocytes
least numerous of the granulocytes
constitute about 0.5–1% of the total number of leukocytes
always exhibit a bilobed nucleus and abundant blue-violet granules
in the cytoplasm
21-32
Leukocytes
Agranulocytes (2)
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Agranulocytes are leukocytes that have such small
granules in their cytoplasm that they are frequently
overlooked upon casual observation—hence the
name agranulocyte.
Agranulocytes include
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4. lymphocytes
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5. monocytes.
21-33
Leukocytes – Agranulocytes Lymphocytes
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T-lymphocytes (T-cells)
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B-lymphocytes (B-cells)
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manage and direct an immune response
some directly attack foreign cells and virusinfected cells
stimulated to become plasma cells and produce
antibodies
Natural killer cells (NK cells)
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attack abnormal and infected tissue cells
21-34
Leukocytes – Agranulocytes Monocytes
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Up to three times the diameter of an erythrocyte.
Constitute about 3–8% of all leukocytes.
Nucleus is kidney-shaped or U-shaped.
Their job is…..
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Macrophages phagocytize bacteria, cell fragments, dead
cells, and debris.
21-35
Platelets
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Irregular, membrane-enclosed cellular fragments that are about 2
micrometers in diameter (less than one-fourth the size of an
erythrocyte).
In stained preparations, they exhibit a dark central region.
Sometimes called thrombocytes.
Continually produced in the red bone marrow by cells called
megakaryocytes.
Severe trauma to a blood vessel causes the blood to coagulate,
or clot.
Components in the plasma produce a web of fibrin that traps
erythrocytes and platelets in the web to halt blood flow.
21-36