Transcript Blood - BowNET

Red Blood Cells
Formation and structure
Regulation of RBC Production

Decrease in oxygen in blood
Hemorrhage
 Excessive RBC destruction
 Decreased oxygen availability

• Hypoxia

Higher altitudes  decreased oxygen
availability
Platelets

Also called thrombocytes.


Smallest of formed elements.
Important in blood clotting:
Constitute most of the mass of the clot.
 Release serotonin to reduce blood flow to
area and ADP to cause pseudopodia to
grow.
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Secrete growth factors

Maintain the integrity of blood vessel wall.
RED BLOOD CELL
ABNORMALITIES

Anemia

Polycythemia

Sickle Cell Anemia
Anemia
General definition – reduced O2 carrying capacity
Causes:
• Low number of erythrocytes
• Hemorrhage – blood loss
• Hemolytic – ruptured RBC’s
• Aplastic – inability of bone marrow to
synthesize RBC

Decreased hemoglobin
• Iron-deficiency
• Athletes anemia – expanded blood volume
• Pernicious anemia – B12 deficiency or lack
factor for B12 absorption
Polycythemia

Over production of RBCs
 Hematocrit = 80% (normal = 45%)
 Cause: bone marrow cancer
 Symptoms: headache, dizziness, blood clots

Secondary causes
 Adaptation to high altitude
 Blood doping
 Supplemental Erythropoeitin
Sickle Cell Anemia

Shape of erythrocyte is altered
1 amino acid (out of 267) is different in
hemoglobin
 Blood cells have a crescent shape
 Decreased organ blood flow

White blood cells (Leukocytes)
How do they differ from erythrocytes?
1.
Contain nuclei and other cell organelles
2.
Almost invisible under a microscope
3.
Lifespan: 12 hours300 days
Types of Leukocytes:
•
Neutrophils, lymphocytes, monocytes,
eosinophils, basophils
Bacterial or viral infection: increased WBC production
WBC disorders

Leukopenia – low WBC count (nutrition/
radiation)

Leukemia – cancer of WBC

Large number of immature, non-functioning
WBCs
• Anemia
• Hemorrhage
• Massive infections
Blood types

RBC plasma membranes have specific
antigens which are unique
• A,B,AB (universal recipient), O (universal donor)
• Rh negative or Rh positive (85% of population)
Red Blood Cell Antigens

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ABO system:
Major group of antigens of RBCs.
 Type A:
• Only A antigens present.
 Type B:
• Only B antigens present.
 Type AB:
• Both A and B antigens present.
 Type O:
• Neither A or B antigens present.
RBC Antigens

Type B:
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Type AB:

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May have inherited B gene from each parent.
May have inherited B gene from 1 parent and O
gene from the other parent.
Inherited the A gene from one parent and the B
gene from the other parent.
Type O:

Inherited O gene from each parent.
Transfusion Reactions


If blood types do not match, the recipient’s
antibodies attach to donor’s RBCs and
agglutinate.
Type O:
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Universal donor.
Recipient’s antibodies cannot agglutinate the
donor’s RBCs.
Type AB universal recipient:
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Lack the anti-A and anti-B antibodies.
Cannot agglutinate donor’s RBCs.
Rh Factor
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Another group of antigens found on RBCs.
Rh positive:
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Rh negative:
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Have these antigens.
Do not have these antigens.
Significant when Rh negative mother give
birth to Rh positive baby.
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At birth, mother may become exposed to Rh
positive blood of fetus.
Mother at subsequent pregnancies may produce
antibodies against the Rh factor.
Fig. 4.12
Reading thus far:
Pages 366-375: Circulatory system, WBC,
RBC, hematopoiesis, hemostasis, blood types
Pages 378-383: Heart anatomy, structure,
cardiac circulation
Page 354: Cardiac muscle fibers