Download Composition of Blood

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Dr. Gihan Gawish
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 Blood measures about 5 liters in the adult human
and accounts for 8 percent of the body weight.
 Blood cells are formed in the bone marrow, the
soft, spongy center of bones.
 New (immature) blood cells are called blasts.
Some blasts stay in the marrow to mature.
Some travel to other parts of the body to mature.
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
Blood is one of the connective tissue .
It consists of
Hematic cells
Erythrocytes
(Red blood cells(
Matrix (plasma).
Platelets
Leucocytes
(White blood cells)
Because blood has many functions you might be able to conclude that the
blood is composed of many different parts.
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Whole blood
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Centrifuge
anticoagulant
Plasma
 Plasma takes up about 55% of the total volume
of the blood.
 Cells free serum or plasma, can be obtained by
centrifugation.
 The plasma is a slightly alkaline fluid, with a
typical yellowish color.
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Composition of plasma
 It consists of 90 % water and 10% dry matter.
 The other 10% contains many types of
molecules,
including
nutrients,
glucose,
vitamins, cellular wastes, salts, and proteins.
 There are three major types of proteins which
exist in plasma )albumin, fibrinogen, and
globulins(
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Functions of plasma proteins
 The albumin keeps water from leaving the blood and
entering the surrounding cells by osmosis. It does this
by helping to keep the concentration of the water within
the blood the same as the concentration in the body
tissues.
 The fibrinogen aids in the clotting of the blood.
 Some globulins transport proteins and other substances
from one part of the body to the next.
 Other globulins are known as antibodies, which help to
fight of infection. Antibodies are proteins that attach to
and help destroy foreign substances in the body .
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Hematic cells
1. Red blood cells
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 The human body
millions/mm3 of blood
contains
approximately
5
 In humans, the matured red blood cells do not contain a
nuclei.
 Their cytoplasm is filled with an iron-containing protein
called hemoglobin.
 Hemoglobin is the substance that gives the blood its red
color.
 When a person has an insufficient amount of
hemoglobin or too few red blood cells, this is referred
to as anemia. Both of these conditions lowers the
amount of oxygen that can be carried throughout the
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blood.
 New cells are produced at the same rate red
blood cells are destroyed .
 The old red cells are removed from the body
by the spleen and liver and are then broken
down.
 The iron from the hemoglobin is then
collected and reused .
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Function of RBCs
 The red blood cells transport oxygen
from the lungs to the tissues in the
body.
 They also carry carbon dioxide from
the body tissues to the lungs.
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Hematic cells
2. Platelets (thrombocytes)
 The part of the blood which is involved in the clotting of
blood.
 Platelets are formed when bits of cytoplasm are
pinched. Even though these bits of cytoplasm contain no
nuclei, they surrounded by a membrane.
 There about a total of 1.5 trillion platelets in the blood of an
adult human.
 There are about 300,000 platelets existing in a cubic
millimeter of blood.
 Their life lasts for about seven days and are produced at
about
200 billion /day.
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Hematic cells
3. White blood cells (LEUKOCYTES)
Granulocyte
Neutrophil
Eosinophil
Agranulocyte
(lymphoid cells)
Basophil
Lmphocytes
Monocytes
 The term granulocyte is due to the presence of granules in the
cytoplasm of these cells. These granules have a different affinity
towards neutral, acid or basic stains and give the cytoplasm different
colors.
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3
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 There is a variety of colorless blood cells which make
the white blood cells, or known as leukocytes.
 These white blood cells are defenders for the
body. They protect the body from bacteria and viruses,
which are disease-causing organisms.
 Unlike red blood cells, the white blood cells contain a
nucleus and are larger than the red blood cells.
 There are fewer white blood cells than red, but there
are still about 60 billion in an adult human body.
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Function of WBCs
 There are five different types of white blood
cells.
 The majority of them function to protect the
body in some form.
 A portion of the white blood cells are what are
called phagocytic (monocytes & neutrophils).
 The lymphocytes take care of the production of
antibodies and the cells that destroy certain
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substances
and uncommon cells.
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 The body consists of metabolically active cells
that need a continuous supply of nutrients and
oxygen.
 Metabolic waste products need to be removed
from the cells to maintain a stable cellular
environment.
 Blood is the primary transport medium that is
responsible for meeting these cellular demands.
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The transport functions include:
 Carrying oxygen and nutrients to the cells .
 Transporting carbon dioxide and nitrogenous
wastes from the tissues to the lungs and kidneys
where these wastes can be removed from the
body .
 Carrying hormones from the endocrine glands to
the target tissues .
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The regulation functions include:
 Helping regulate body temperature by removing heat
from active areas, such as skeletal muscles, and
transporting it to other regions or to the skin where it
can be dissipated.
 Playing a significant role in fluid and electrolyte
balance because the salts and plasma proteins contribute
to the osmotic pressure.
 Functioning in pH regulation through the action of
buffers in the blood.
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The protection functions include:
 Preventing fluid loss through hemorrhage when
blood vessels are damaged due to its clotting
mechanisms.
 Helping (phagocytic white-blood cells) to protect
the body against microorganisms that cause
disease by engulfing and destroying the agent.
 Protecting (antibodies in the plasma) protect
against disease by their reactions with offending
agents.
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Total volume
 It measures about 5 liters in the adult human
and accounts for 8 percent of the body
weight.
 Infants have a large amount of blood volume
in proportion to their body weight compared
to the body weight of adult
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Hematocrite
 Hematocrite= (length of RBC column / Total length of
blood column) x 100
 The range of hematocrite in males is from 42% to 52%
 The range of hematocrite in females is from 37% to 47%
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Specific Gravity
 SG= density of blood / density of water OR
= mass of given wt of blood / mass of equal wt. water
 SG of blood ≈ 1.055 to 1.065
 It means the density of blood more than of
water
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Viscosity
 The viscosity of plasma is about 1.8-times the
viscosity of water (termed relative viscosity at
37°C) and is related to the protein composition
of the plasma.
 Whole blood has a relative viscosity of 3-4
depending upon hematocrit, temperature, and
flow rate .
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 Hematocrit : Therefore, a 50% increase in hematocrit from a
normal value increases blood viscosity by about 100%. Such
changes in hematocrit and blood viscosity occur in a patients with
polycythemia.
 Temperature : As temperature decreases, viscosity
increases. Viscosity increases approximate 2% for each
°C decrease in temperature. This effect has several
implications.
 The flow rate : At very low flow states in the
microcirculation, as occurs during circulatory shock, the
blood viscosity can increase quite significantly.
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Osmotic pressure of the Blood ≈ 25mmHg
 It is the hydrostatic pressure produced by a solution in a space
divided by a semi permeable membrane due to a differential in
the concentrations of solute.
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 Osmotic potential is the opposite of water
potential with the former meaning the degree to
which a solvent (usually water) would want to
stay in a liquid.
 When a biological cell is in a hypotonic
environment (the cell interior contains a lower
concentration of water and a higher concentration
of other molecules than its exterior), water flows
across the cell membrane into the cell, causing it
to expand due to osmotic pressure.
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