Transcript Blood Cells

Blood
Human Anatomy and Physiology
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Introduction
• Blood, a type of connective tissue, is a complex
mixture of cells, chemicals, and fluid.
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• Blood transports substances throughout the body,
and helps to maintain a stable internal
environment.
• The blood includes red blood cells, white blood
cells, platelets, and plasma.
• There are about one billion red blood cells in two
to three drops of blood. For every 600 red blood
cells, there are about 40 platelets and one white
cell.
Blood Volume and Composition
• An average-sized adult has a blood volume of about 5.3
quarts (5 liters).
• A blood hematocrit is normally 45% cells and 55%
plasma.
• Plasma is a mixture of water, amino acids, proteins,
carbohydrates, lipids, vitamins, hormones, electrolytes,
and cellular wastes.
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Blood Cells – Red Blood Cells
•
Red blood cells (erythrocytes) are biconcave
disks that contain one-third oxygen-carrying
hemoglobin by volume.
•
When oxygen combines with hemoglobin bright
red oxyhemoglobin results.
Deoxygenated blood (deoxyhemoglobin) is
darker.
Red blood cells discard their nuclei during
development and so cannot reproduce or produce
proteins.
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Red Blood Cell Production
and Its Control
•
In the embryo and fetus, red blood cell
production occurs in the yolk sac, liver, and
spleen; after birth, it occurs in the red
bone
marrow. Red marrow can be found in the flat
bones and in the spongy bone located in the
epiphysis of the long bones.
•
The average life span of a red blood cell is 120
days.
The total number of red blood cells remains
relatively constant due to a negative feedback
mechanism utilizing the hormone erythropoietin.
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Erythropoietin
 Hormone released from the kidneys and liver in response to the
detection of low oxygen levels.
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Dietary Factors Affecting
Red Blood Cell Production
• Vitamins B12 and folic acid are needed for DNA
synthesis, so they are necessary for the
reproduction of all body cells, especially in
hematopoietic (blood cell producing) tissue.
• Iron is needed for hemoglobin synthesis.
• A deficiency in red blood cells or quantity of
hemoglobin results in anemia.
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Anemia
• Anemia is a condition in which the body does not
have enough healthy red blood cell
• The body needs certain vitamins, minerals, and nutrients
to make enough red blood cells. Iron, Vitamin B12, and
folic acid are three of the most important ones.
• Symptoms of Anemia:
• You may have no symptoms if the anemia is mild. Some
of the first symptoms include feeling grumpy, tired,
headaches, or problems thinking.
• As symptoms progress, symptoms may include brittle
nails, light headedness, pale skin, sore tongue, shortness
of breath.
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Red Blood Cells
•
With age, red blood cells become increasingly fragile
and are damaged by passing through narrow
capillaries.
•
Macrophages in the liver and spleen phagocytize
damaged red blood cells.
Hemoglobin from the decomposed red blood cells is
converted into heme and globin.
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Heme is decomposed into iron which is stored or
recycled and biliverdin and bilirubin which are
excreted in bile.
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Types of White Blood Cells
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White blood cells (leukocytes) help defend the
body against disease.
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Five types of white blood cells are in circulating
blood and are distinguished by size, granular
appearance of the cytoplasm, shape of the
nucleus, and staining characteristics.
They are formed from hemocytoblasts
(hematopoietic stem cells).
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Types of White Blood Cells
Granulocytes
Agranulocytes
• Neutrophils have red-staining
• Monocytes are the largest
fine granules and a multi-lobed
nucleus; they comprise 54-62%
of leukocytes.
• Eosinophils have coarse
blood cells, have variablyshaped nuclei, and make up
3-9% of circulating
leukocytes.
• Lymphocytes are long-lived,
granules that stain deep red, a
have a large, round nucleus,
bilobed nucleus, and make up
and account for 25-33% of
only 1-3% of circulating
circulating leukocytes
leukocytes.
• .Basophils have fewer granules
that stain blue; they account for
fewer than 1% of leukocytes.
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Neutrophil
Eosinophil
Basophil
Lymphocyte
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Monocyte
Functions of White Blood Cells
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Leukocytes (WBCs) can squeeze between cells lining
walls of blood vessels and attack bacteria and debris.
Neutrophils and Monocytes
 Both are phagocytic, with monocytes engulfing the larger particles.
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Eosinophils
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• moderate allergic reactions
• defend against parasitic infections
• Includes mast cells that migrate to
Basophils damaged tissues and release histamine
to promote inflammation and heparin
to inhibit blood clotting.
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Lymphocytes
• The major players in specific immune reactions
• Some produce antibodies
• Originate from stem cells and differentiate into either B cells or T
cells in lymphoid tissue (thymus or bone marrow)
• Found in lymph and blood
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White Blood Cell Counts
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Leukocytosis occurs after an infection when
excess numbers of leukocytes are present.
Leukopenia occurs from a variety of conditions,
including AIDS, in which low numbers of
leukocytes are present.
A differential white blood cell count can help
pinpoint the nature of an illness, indicating
whether it is caused by bacteria or viruses.
• It lists the percentages of the types of
leukocytes in a blood sample.
Blood Platelets
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•
Blood
platelets
megakaryocytes.
•
Platelets help repair damaged blood vessels by
adhering to their broken edges.
are
fragments
of
Blood Plasma
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Plasma is the clear, straw-colored fluid portion of
the blood.
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Mostly water
substances.
but
contains
a
variety
of
-
Transports nutrients
and gases, regulates
fluid and electrolyte balance, and maintains a
favorable pH.
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Plasma Proteins
 The plasma proteins remain in the blood and interstitial fluids and
are not normally used as energy sources.
 Three major types: albumins, globulins, and fibrinogen
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Nutrients and Gases
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The most important blood gases are oxygen and carbon
dioxide.
The plasma nutrients include amino acids,
monosaccharides, nucleotides, and lipids.
• Since lipids are not soluble in the water of the plasma,
they are surrounded by protein molecules for transport
through the bloodstream as lipoproteins.
- Lipoproteins are classified on the basis of their
densities, which reflects their composition.
- Types of lipoproteins include HDL, LDL, VLDL, and
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chylomicrons.
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nonprotein Nitrogenous Substances
 Generally include amino acids, urea, and uric acid.
 Urea and uric acid are the by-products of protein and
nucleic acid catabolism.
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Plasma Electrolytes
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Plasma electrolytes are absorbed by the intestine
or are by-products of cellular metabolism.
They include sodium, potassium, calcium,
magnesium, chloride, bicarbonate, phosphate,
and sulfate ions.
Some of these ions are important in maintaining
osmotic pressure and pH of the plasma.
Hemostasis
• Hemostasis refers to the stoppage of bleeding.
• Following injury to a vessel, three steps occur in
hemostasis:
1. blood vessel spasm
2. platelet plug formation
3. blood coagulation.
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Blood Vessel Spasm
• Cutting a blood vessel causes the muscle in its
walls to contract in a reflex, or engage in
vasospasm.
• This reflex lasts only a few minutes, but it lasts
long enough to initiate the second and third steps
of hemostasis.
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Platelet Plug Formation
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Platelets stick to the exposed edges of damaged
blood vessels, forming a net with spiny processes
protruding from their membranes.
•
A platelet plug is most effective on a small
vessel.
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Blood Coagulation
• Blood coagulation is the most effective means of
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hemostasis.
Blood coagulation is very complex and uses clotting
factors.
Once a blood clot forms, it promotes still more
clotting through a positive feedback system.
After a clot forms, fibroblasts invade the area and
produce fibers throughout the clots.
A clot that forms abnormally in a vessel is a
thrombus; if it dislodges, it is an embolus.
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Blood Groups
and Transfusions
Antigens and Antibodies
• Clumping of red blood cells following transfusion
is called agglutination.
• Agglutination is due to the interaction of proteins
on the surfaces of red blood cells (antigens) with
certain antibodies carried in the plasma.
• Only a few of the antigens on red blood cells
produce transfusion reactions.
- These include the ABO group and Rh group.
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ABO Blood Group
• Type A blood has A antigens
on red blood cells and anti-B
antibodies in the plasma.
• Type B blood has B antigens
on red blood cells and anti-A
antibodies in the plasma.
• Type AB blood has both A
and B antigens, but no
antibodies in the plasma.
• Type O blood has neither
antigen, but both types of
antibodies in the plasma
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ABO Blood Group
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Adverse transfusion reactions are avoided by preventing the
mixing of blood that contains matching antigens and
antibodies.
Adverse reactions are due to the agglutination of red blood
cells
Blood Types & Transfusion Possibilities
Blood Type
Antigens
Antibodies
Can Receive
Can Donate
To
A
A
anti-B
O, A
A, AB
B
B
anti-A
O, B
B, AB
AB
A,B
none
all
AB
O
O
both anti-A
and anti-B
only O
all
Rh Blood Group
• The Rh factor was named after the rhesus monkey.
• If the Rh factor surface protein is present on red blood
cells, the blood is Rh positive; otherwise it is Rh
negative.
• There are no corresponding antibodies in the plasma
unless a person with Rh-negative blood is transfused
with Rh-positive blood; the person will then develop
antibodies for the Rh factor.
• Erythroblastosis fetalis develops in Rh-positive fetuses
of Rh-negative mothers but can now be prevented.
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Blood Types
in the U.S.
Blood Type & Rh
Frequency
• O Rh Positive
37.4%
• O Rh Negative
6.6%
• A
Rh Positive
35.7%
• A
Rh Negative
6.3%
• B
Rh Positive
8.5%
How Many Have It
1 person in 3
1 person in 15
1 person in 3
1 person in 16
1 person in 12
Blood TYpes
• Most common blood type is type O +
• Least common blood type is AB -
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Blood Typing
To determine a
blood type, we
different serums
samples and see
form.
person ’ s
add three
to blood
if clumps
Clumps = Positive (+)
No Clumps = Negative (-)
14. Use the results shown
to determine the blood
type for each sample.
+ = Clump
- = No Clumps
A
Rh
What would the blood type
be for this sample?
B
#13
Blood Type: ___
A
Blood Typing
A
Rh
Use the results shown to determine the
blood type for each sample.
B
Rh
B
Blood Type: ___
+ = present
A
A
Rh
- = absent
B
A
Rh
B
Blood Type: ___
Blood Type: ___
Rh
B
Blood Type: ___
Blood Type: ___
• Universal Recipient has blood type AB+
• Universal Donor has blood type O-
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