Chapter 17 Blood Flashcards
Blood leaves the heart via
arteries
Arteries branch
repeatedly until they become capillaries
oxygen and nutrients diffuse across
capillary walls and enter tissues
carbon dioxide and wastes move from
tissues into the blood
oxygen-deficient blood leaves the
capillaries and flows in veins to the heart
after oxygen-deficient blood flows to the heart it then flows to the
lungs where it releases CO2 and picks up O2
The oxygen-rich blood returns to the
heart
Blood is the body’s only
fluid tissue
Blood is composed of
liquid plasma (55%0 and formed elements (45%)
Formed elements include:
Erythrocytes or red blood cells (RBCs)
Leukocytes or white blood cells (WBCs)
Platelets
Hematocrit
the percentage of RBCs out of the total blood volume
Components of whole blood
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blood is ______, __________ with a ________.
sticky, opaque fluid with a metallic taste
Blood color varies from
scarlet to dark red
the pH of blood is
7.35-7.45
the temperature of blood is
38 degrees Celcius
Blood accounts for approximately ____ of body weight.
8%
The average volume for males
5-6L
The average volume for females
4-5L
blood performs a number of functions dealing with:
- substance distribution
- Regulation of blood levels of particular substances
- body protection
Blood transports
- oxygen from the lungs and nutrients from the digestive tract
- metabolic wastes from cells to the lungs and kidneys for elimination
- hormones from endocrine glands to target organs
Blood maintains
- appropriate body temperature by absorbing and distributing heat
- normal pH in body tissues using buffer systems
- adequate fluid volume in the circulatory system
Blood prevents blood loss by:
- activating plasma proteins and platelets
* initiating clot formation when a vessel is broken
blood prevents infection by:
- synthesizing and utilizing antibodies
- activating complement proteins
- activating WBCs to defend the body against foreign invaders
Erythrocytes, leukocytes, and platelets make up the
formed elements
Only WBCs are
complete cells
RBCs have no nuclei or organelles, and platelets are just
cell fragments
most formed elements survive in the bloodstream
for only a few days
Erythrocytes (RBCs) are biconcave discs, anucleate, essentially
no organelles
Erythrocytes (RBCs) are filled with
hemoglobin (Hb), a protein that functions in gas transport
Erythrocytes (RBCs) structural characteristics contribute to its gas transport function:
- Biconcave shape has a huge surface area relative to volume
* Erythrocytes are more than 97% hemoglobin
Erythrocytes (RBCs)
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Components of whole blood
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Erythrocytes (RBCs) are dedicated to
respiratory gas transport
Hb reversibly binds with oxygen and most
oxygen in the blood is bound to Hb
Each Hb molecule can transport
4 molecules of oxygen
Structure of hemoglobin
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Oxyhemoglobin
Hb bound to oxygen
*oxygen loading takes place in the lungs
Deoxyhemoglobin
Hb after oxygen diffuses into tissues (reduced Hb)
Carbaminohemoglobin
Hb bound to carbon dioxide
*carbon dioxide leading takes place in the tissues
Hematopoiesis
blood cell formation
Hematopoiesis occurs in the
red bone marrow
the life span of an erythrocyte is
100-120 days
Old RBCs become rigid and fragile, and their
Hb begins to degenerate
dying RBCs are engulfed by
macrophages
Heme and globin are separated and the iron is
salvaged for reuse
Erythrocyte disorders
anemia-blood has
abnormally low oxygen-carrying capacity
Polycythemia-excess RBCs that
increase blood viscosity
Three main polycythemias are
- polycythemia vera
- secondary polycythemia
- blood doping
Leukocytes (WBCs) are the only blood components that are
complete cells
Leukocytes (WBCs) are less
numerous than RBCs
Leukocytes (WBCs) make up
1% of the total blood volume
Leukocytes are broken down into
granulocytes and agranulocytes
Percentage of Leukocytes
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Granulocytes
neutrophils, eosinophils, and basophils
Granulocytes contain
cytoplasmic granules that sain specifically (acidic, basic, or both) with Wright’s stain
Granulocytes are
larger and usually shorter-lived than RBCs
Granulocytes have lobed
nuclei
Granulocytes are all
phagocytic cells
Neutrophils have to types of granules that:
- take up both acidic and basic dyes
- give the cytoplasm a lilac color
- contain peroxidases, hydrolytic enzymes, and defensins (antibiotic-like proteins)
Neutrophils are our body’s
bacteria slayers
Neutrophils make up
50%-70% of the differential WBC count
Eosinophils account for
1%-4% of WBCs
Eosinophils have red-staining, bilobed nuclei via a
broad band of nuclear material
Eosinophils have red to crimson (acidophilic)
large, course, lysosome-like granules
Eosinophils lead the body’s counterattack against
parasitic worms
Eosinophils lessen the severity of
allergies by phagocytizing immune complexes
Basophils account for
0.5% of WBCs
Basophils have
U- or S-shaped nuclei with two or three conspicuous constrictions
Basophils are functionally similar to
mast cells
Basophils have large, purplish-black (basophilic)
granules that contain histamine
histamine
an inflammatory chemical that acts as a vasodilator and attracts other WBCs (antihistamines counter this effect)
Argranulocytes are ______ and ______.
lymphocytes and monocytes
Argranulocytes lack
visible cytoplasmic granules
Argranulocytes are similar structurally but are
functionally distinct and unrelated cell types
Argranulocytes have _____ or ______ nuclei
spherical (lymphocytes or kidney-shaped (monocytes)
Lymphocytes account for
25% or more of WBCs
Lymphocytes have large, dark purple
circular nuclei with a thin rim of blue cytoplasm
Lymphocytes are found mostly enmeshed in
lymphoid tissue (some circulate in the blood)
There are two types of lymphocytes:
T cells and B cells
T cells
function in the immune response
B cells
give rise to plasma cells, which produce antibodies
Monocytes account for
4-8% of leukocytes
Monocytes are the
largest leukocytes
Monocytes have abundant pale-blue
cytoplasms
Monocytes have purple staining,
U- or kidney-shaped nuclei
Monocytes leave the circulation, enter tissue and differentiate into
macrophages
Macrophages are highly
mobile and actively phagocytic
Macrophages activate
lymphocytes to mount an immune response
Leukocytes
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Summary of formed elements
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Leukocytes disorders
Leukemias-leukemia refers to
cancerous conditions involving WBCs
Immature WBCs are found in the
bloodstream in all leukemias
The WBCs produced, though numerous,
are not functional (leukemia)
Platelets are
fragments of megakaryocytes with a blue-staining outer region and a purple granular center
Platelets function in the
clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels
Substances used to prevent undesirable clots:
aspirin, heparin, and warfarin
Asprin
an anti-prostaglandin that inhibits thromboxane A2
Heparin
an anticoagulant used clinically for pre- and postoperative cardiac care
Warfarin
used for those prone to atrial fibrillation
The ABO blood groups consist of:
- two antigens (agglutinogens) (A and B) on the surface of the RBCs
- two antibodies )agglutinins) in plasma (anti-A and anti-B)
The ABO blood groups may ave various types of
antigens and preformed antibodies
Agglutinogens and their corresponding antibodies cannot be
mixed without serious hemolytic reactions
ABO Blood Groups
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Presence of the Rh agglutinogens on RBCs is indicated as
Rh+
Anti-Rh antibodies are not spontaneously formed in
Rh- individuals
If an Rh- individual receives Rh+ blood,
anti-Rh antibodies form
A second exposure to Rh+ blood will result in a
typical transfusion reaction
Hemolytic disease of the newborn -Rh+ antibodies of sensitized Rh- mother cross the placenta and attack and destroy the
RBCs of an Rh+ baby
Rh- mother becomes sensitized when the exposure of Rh+ blood causes her body to
synthesize Rh+ antibodies
The drug RhoGAM can prevent the Rh- mother from becoming
sensitized
Treatment of hemolytic disease of the newborn involves pre-birth
transfusions and exchange transfusions after birth
When serum containing anti-A or anti-B agglutinins is added to blood,
agglutination will occur between the agglutinin and the corresponding agglutinogen
Positive reactions indicate
agglutination
Blood Typing
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