Blood HISTOLOGY
○ O2 - bound to hemoglobin in erythrocytes (much more
1` q1` 2-
OUTLINE
abundant in arterial than venous blood)
I. BLOOD ○ CO2 - carried in solution as CO2 or HCO3- in addition to
II. COMPOSITION OF PLASMA
being hemoglobin-bounds
III. BLOOD CELLS
○ Nutrients - distributed from their sites of synthesis or
Erythrocytes
Leukocytes absorption in the gut
Granulocytes ○ Metabolic residues - collected from cells throughout the body
Neutrophils and removed from the blood by the excretory organs
Eosinophils ○ Hormone distribution in blood - permits the exchange of
Basophils chemical messages between distant organs regulating
Agranulocytes normal organ function
Lymphocytes ● Blood also participates in heat distribution, the regulation of
Monocytes body temperature, and the maintenance of acid-base and
Platelets osmotic balance.
● Leukocytes
BLOOD ○ One of the body’s chief defenses against infection
○ Spherical and inactive while suspended in circulating blood
● A specialized CT consisting of cells and fluid extracellular
○ When called to sites of infection or inflammation, they cross
material called plasma
the wall of venules
● Formed elements circulating in the plasma ○ Become motile and migrate into the tissues and display their
○ Erythrocytes (RBC) defensive capabilities
○ Leukocytes (WBC)
○ platelets
● Serum COMPOSITION OF PLASMA
○ A pale-yellow liquid
○ Contains growth factors and other proteins released from
platelets during clot formation, which confer biological
properties very different from those of plasma
● Hematocrit
○ Erythrocytes comprise the sedimented material and their
volume, normally about 44% of the total blood volume in
healthy adults
● Plasma
○ Straw-colored, translucent, slightly viscous supernatant
comprising 55% at the top half of the centrifugation tube
○ Buffy coat - a thin gray-white layer between plasma and the
hematocrit
■ About 1% of the volume
■ Consists of leukocytes and platelets, both less dense than
erythrocytes
● Plasma
○ An aqueous solution with pH 7.4
○ Contain substances of low or high molecular weight that make
up 7% of its volume
○ Electrolytes - include nutrients, respiratory gases, nitrogenous
waste products, hormones, and inorganic ions
● Through the capillary walls, the low-molecular-weight
components of plasma are in equilibrium with the interstitial fluid
of the tissues.
● The composition of plasma is usually an indicator of the mean
composition of the extracellular fluids in tissues.
● Plasma - 55% of whole blood
○ Water - 92%
○ Proteins - 7%
○ Other solutes - 1%
● Erythrocytes - 44% of whole blood
Major plasma proteins
● Albumin
○ Most abundant plasma protein
Functions of the blood ○ Made in the liver and serves primarily to maintain the
osmotic pressure of the blood
● A distributing vehicle, transporting O2, CO2, metabolites, ● Globulins (α- and β-globulins)
hormones, and other substances to cells throughout the body
1 of 13
, Blood
○ made by liver and other cells, include transferrin and other Erythrocytes
transport factors; fibronectin; prothrombin and other ● Red blood cells or RBCs
coagulation factors; lipoproteins and other proteins entering ● Terminally differentiated structures lacking nuclei and completely
blood from tissues. filled with the O2-carrying protein hemoglobin
● Immunoglobulins (antibodies or γ-globulins) ● The only blood cells whose function does not require them to
○ secreted by plasma cells in many locations leave the vasculature
● Fibrinogen ● Flexible biconcave discs,~7.5 µm in diameter, 2.6-µm thick at
○ the largest plasma protein the rim, but only 0.75-µm thick in the center.
○ made in the liver, which, during clotting, polymerizes as ○ can be used as an internal standard to estimate the size of
insoluble, cross-linked fibers of fibrin that block blood loss other nearby cells or structures
from small vessels. ○ provides a large surface-to-volume ratio and facilitates gas
● Complement proteins exchange.
○ comprise a defensive system important in inflammation and ● Normal concentration of erythrocytes in blood
destruction of microorganisms. ○ 3.9-5.5 million per microliter in women
○ 4.1-6.0 million/µL in men.
● quite flexible, which permits them to bend and adapt to the small
diameters and irregular turns of capillaries
● Cuplike shape
● Rouleaux - In larger blood vessels RBCs may adhere to one
another loosely in stacks
● Erythrocyte plasmalemma - best-known membrane of any cell
due to its ready availability
○ 40% lipid
○ 10% carbohydrate
○ 50% protein
○ Integral proteins include ion channels, the anion transporter
(band 3 protein and glycophorin A)
■ The glycosylated extracellular domains of the latter
proteins include antigenic sites that form the basis for the
ABO blood typing system
○ Peripheral proteins
■ Spectrin - dimers of which form a lattice bound to
underlying actin filaments
■ Ankyrin - anchors the spectrin lattice to the glycophorins
and band 3 proteins.
○ This submembranous meshwork stabilizes the membrane,
maintains the cell shape, and provides the cell elasticity
required for passage through capillaries.
● Erythrocyte cytoplasm lacks all organelles but is densely filled
with hemoglobin
○ Hemoglobin - the tetrameric O2 -carrying protein that
accounts for the cells’ uniform acidophilia
■ When combined with O2 or CO2, hemoglobin forms
oxyhemoglobin or carbaminohemoglobin, respectively.
■ The reversibility of these combinations is the basis for the
protein’s gas-transporting capacity.
● Lifespan: 120 days
○ defects in the membrane’s cytoskeletal lattice or ion transport
systems begin to produce swelling or other shape
abnormalities, changes in the cells’ surface oligosaccharide
complexes.
○ Senescent or wornout RBCs - are recognized and removed
from circulation, mainly by macrophages of the spleen, liver,
and bone marrow.
BLOOD CELLS
● Blood smears are routinely stained with mixtures of acidic
(eosin) and basic (methylene blue) dyes.
○ may contain dyes called azures that are more useful in
staining cytoplasmic granules containing charged proteins
and proteoglycans.
○ Azurophilic granules produce metachromasia in stained
leukocytes like that seen with mast cells in connective tissue. MEDICAL APPLICATION
○ Some of these special stains - Giemsa and Wright stain ● Anemia - the condition of having a concentration of
erythrocytes below the normal range
HISTOLOGY 2 of 13
○ O2 - bound to hemoglobin in erythrocytes (much more
1` q1` 2-
OUTLINE
abundant in arterial than venous blood)
I. BLOOD ○ CO2 - carried in solution as CO2 or HCO3- in addition to
II. COMPOSITION OF PLASMA
being hemoglobin-bounds
III. BLOOD CELLS
○ Nutrients - distributed from their sites of synthesis or
Erythrocytes
Leukocytes absorption in the gut
Granulocytes ○ Metabolic residues - collected from cells throughout the body
Neutrophils and removed from the blood by the excretory organs
Eosinophils ○ Hormone distribution in blood - permits the exchange of
Basophils chemical messages between distant organs regulating
Agranulocytes normal organ function
Lymphocytes ● Blood also participates in heat distribution, the regulation of
Monocytes body temperature, and the maintenance of acid-base and
Platelets osmotic balance.
● Leukocytes
BLOOD ○ One of the body’s chief defenses against infection
○ Spherical and inactive while suspended in circulating blood
● A specialized CT consisting of cells and fluid extracellular
○ When called to sites of infection or inflammation, they cross
material called plasma
the wall of venules
● Formed elements circulating in the plasma ○ Become motile and migrate into the tissues and display their
○ Erythrocytes (RBC) defensive capabilities
○ Leukocytes (WBC)
○ platelets
● Serum COMPOSITION OF PLASMA
○ A pale-yellow liquid
○ Contains growth factors and other proteins released from
platelets during clot formation, which confer biological
properties very different from those of plasma
● Hematocrit
○ Erythrocytes comprise the sedimented material and their
volume, normally about 44% of the total blood volume in
healthy adults
● Plasma
○ Straw-colored, translucent, slightly viscous supernatant
comprising 55% at the top half of the centrifugation tube
○ Buffy coat - a thin gray-white layer between plasma and the
hematocrit
■ About 1% of the volume
■ Consists of leukocytes and platelets, both less dense than
erythrocytes
● Plasma
○ An aqueous solution with pH 7.4
○ Contain substances of low or high molecular weight that make
up 7% of its volume
○ Electrolytes - include nutrients, respiratory gases, nitrogenous
waste products, hormones, and inorganic ions
● Through the capillary walls, the low-molecular-weight
components of plasma are in equilibrium with the interstitial fluid
of the tissues.
● The composition of plasma is usually an indicator of the mean
composition of the extracellular fluids in tissues.
● Plasma - 55% of whole blood
○ Water - 92%
○ Proteins - 7%
○ Other solutes - 1%
● Erythrocytes - 44% of whole blood
Major plasma proteins
● Albumin
○ Most abundant plasma protein
Functions of the blood ○ Made in the liver and serves primarily to maintain the
osmotic pressure of the blood
● A distributing vehicle, transporting O2, CO2, metabolites, ● Globulins (α- and β-globulins)
hormones, and other substances to cells throughout the body
1 of 13
, Blood
○ made by liver and other cells, include transferrin and other Erythrocytes
transport factors; fibronectin; prothrombin and other ● Red blood cells or RBCs
coagulation factors; lipoproteins and other proteins entering ● Terminally differentiated structures lacking nuclei and completely
blood from tissues. filled with the O2-carrying protein hemoglobin
● Immunoglobulins (antibodies or γ-globulins) ● The only blood cells whose function does not require them to
○ secreted by plasma cells in many locations leave the vasculature
● Fibrinogen ● Flexible biconcave discs,~7.5 µm in diameter, 2.6-µm thick at
○ the largest plasma protein the rim, but only 0.75-µm thick in the center.
○ made in the liver, which, during clotting, polymerizes as ○ can be used as an internal standard to estimate the size of
insoluble, cross-linked fibers of fibrin that block blood loss other nearby cells or structures
from small vessels. ○ provides a large surface-to-volume ratio and facilitates gas
● Complement proteins exchange.
○ comprise a defensive system important in inflammation and ● Normal concentration of erythrocytes in blood
destruction of microorganisms. ○ 3.9-5.5 million per microliter in women
○ 4.1-6.0 million/µL in men.
● quite flexible, which permits them to bend and adapt to the small
diameters and irregular turns of capillaries
● Cuplike shape
● Rouleaux - In larger blood vessels RBCs may adhere to one
another loosely in stacks
● Erythrocyte plasmalemma - best-known membrane of any cell
due to its ready availability
○ 40% lipid
○ 10% carbohydrate
○ 50% protein
○ Integral proteins include ion channels, the anion transporter
(band 3 protein and glycophorin A)
■ The glycosylated extracellular domains of the latter
proteins include antigenic sites that form the basis for the
ABO blood typing system
○ Peripheral proteins
■ Spectrin - dimers of which form a lattice bound to
underlying actin filaments
■ Ankyrin - anchors the spectrin lattice to the glycophorins
and band 3 proteins.
○ This submembranous meshwork stabilizes the membrane,
maintains the cell shape, and provides the cell elasticity
required for passage through capillaries.
● Erythrocyte cytoplasm lacks all organelles but is densely filled
with hemoglobin
○ Hemoglobin - the tetrameric O2 -carrying protein that
accounts for the cells’ uniform acidophilia
■ When combined with O2 or CO2, hemoglobin forms
oxyhemoglobin or carbaminohemoglobin, respectively.
■ The reversibility of these combinations is the basis for the
protein’s gas-transporting capacity.
● Lifespan: 120 days
○ defects in the membrane’s cytoskeletal lattice or ion transport
systems begin to produce swelling or other shape
abnormalities, changes in the cells’ surface oligosaccharide
complexes.
○ Senescent or wornout RBCs - are recognized and removed
from circulation, mainly by macrophages of the spleen, liver,
and bone marrow.
BLOOD CELLS
● Blood smears are routinely stained with mixtures of acidic
(eosin) and basic (methylene blue) dyes.
○ may contain dyes called azures that are more useful in
staining cytoplasmic granules containing charged proteins
and proteoglycans.
○ Azurophilic granules produce metachromasia in stained
leukocytes like that seen with mast cells in connective tissue. MEDICAL APPLICATION
○ Some of these special stains - Giemsa and Wright stain ● Anemia - the condition of having a concentration of
erythrocytes below the normal range
HISTOLOGY 2 of 13
