1. Chapter 11 Blood
Transportation, regulation and
protection

2. Summary
 Blood Composition
 Plasma
 Cells
 Red blood cells
 White blood cells
 Platelets
 Myeloid tissue
 Clotting process
 Blood types

3. Blood Composition
 Blood is a fluid tissue made up of water,
many types of chemicals and millions of
cells.
 Blood volume – 4-6 liters depending on
sex, size and age.
 Color – arterial blood is bright red and
venous blood is dark red.

4. Blood Composition
 pH – normal is 7.35 – 7.45; venous blood
will have a lower pH because it has a
higher concentration of CO2.
 pH (parts hydrogen) is a measure of the amount
of H+ in a solution. Values range from 0-14.
Neutral pH is 7.0 and a pH below 7 is acid while
a pH above 7 is alkaline.
 Blood is slightly ?

5. Blood Composition
 Plasma
 91% water, with proteins (albumen and
globulins), salts, a little oxygen, nutrients,
wastes, hormones, antibodies and clotting
factors.
 Also contains formed elements – cells and cell
fragments.
 Serum – plasma minus the clotting factors;
retains antibodies.

6. Blood Composition - Cells
 Red blood cells (RBCs) or erythrocytes
 Function: transport oxygen to other cells of the body. Key
– hemoglobin contained in the RBC. Hemoglobin (Hgb)
has 4 iron (Fe) atoms that bind O2. Hgb picks up O2 as it
passes through the lungs.
 Life cycle – 120 days
 Normal Hgb – 12-18 grams per 100 ml of blood (dl).
 Normal RBC count – 4.5 – 5.5 million/cubic mm
 Hematocrit – %, volume of RBC in a volume of blood;
normal is 35-50%.

7. Blood Composition - Cells
 Anemia – Term used to describe a number
of different conditions caused by an inability
of the blood to carry sufficient O2 to the
cells of the body. May be a result of low
RBC count or low Hgb.
 Causes – inadequate diet, hemorrhage,
infections, cancers or treatments where the
myeloid tissue is not able to produce enough
RBCs.

8. Blood Composition - Cells
 Anemias
 Pernicious anemia – a deficiency of RBCs due to lack of
vitamin B12.
 Iron deficiency anemia – caused by lack of dietary iron.
 Aplastic anemia – caused by suppression of myeloid
tissue resulting in decreased RBCs. May be due to
radiation or chemical exposure.
 Hemolytic anemia – disorder that causes RBCs to rupture
before the end of their normal life span. Includes malaria
and sickle cell anemia.

9. Blood Composition - Cells
 Other RBC abnormalities
 Polycythemia vera – condition in which the
myeloid tissue produces an excess of RBCs;
blood becomes too thick to flow properly.

10. Blood Composition - Cells
 White Blood Cells (WBCs) or leukocytes
 Normal WBC count = 5,000 to 10,000/microliter
 Buffy Coat – after blood is centrifuged
(separating cells from plasma) the thin layer
between the RBC and the plasma consists of
WBCs and platelets.
 5types of WBCs

11. Blood Composition - Cells
 WBC types
 Neutrophils – phagocytes (phagocytosis means
that they “eat” and destroy invaders, etc.”)
 Eosinophils – defense against parasites; helps
protect the body from irritants that cause
allergies.
 Basophils – function in the inflammatory
response/allergic reactions; produce histamines
and Heparin.

12. Blood Composition - Cells
 WBC types
 Lymphocytes – “B” cells produce antibodies, T-
cells recognize foreign antigens and destroy
them = immune response.
 Monocytes – phagocytes; become macrophages.

13. Blood Composition - Cells
 WBC – abnormalities
 Leukopenia – abnormally low WBC count (viral
infections).
 Leukocytosis – abnormally high WBC count
(bacterial infections)
 Leukemia – malignant disease in which the
number of WBCs increases tremendously but
cells do not function normally.

14. Blood Composition - Cells
 Platelets or thrombocytes
 Not cells but fragments of megakryocytes that
live in the bone marrow.
 Function in the clotting process.
 Normal value – 150,000 to 300,000/cubic
millimeter.
 Thrombocytopenia – low platelet count.

15. Cells – Myeloid Tissue
 2 types of connective tissue that produce
blood cells for the body:
 Myeloid tissue – red bone marrow located in the
sternum, ribs and pelvis. Stem cells produce all
types of blood cells except some lymphocytes
and monocytes.
 Lymphatic tissue – located primarily in the lymph
nodes, thymus, and spleen. Produces
lymphocytes and monocytes.

16. Clotting Process
 Hemostasis – prevention of blood loss.
 Injury to a blood vessel occurs.
 Myogenic response – smooth muscle lining of blood
vessel contracts causing vasoconstriction.
 Rough spot forms on the lining of the vessel (lining is
simple squamous epithelium).
 Platelets break up as they pass over the injured area –
releasing platelet factors that make the platelets sticky
and they stick to the wound. (In small vessels the platelet
plug is all that is necessary to stop the bleeding).

17. Clotting Process
 Hemostasis
 Platelet factors combine with prothrombin
(protein manufacture in the liver), calcium and
other substances to form thrombin (an enzyme).
 Thrombin reacts with fibrinogen (a blood protein)
to change it into fibrin that forms a fibrous gel in
the area of the wound. Fibrin is like a web of fine
threads that traps RBCs and form a barrier
across the vessel.

18. Clotting Process
 Hemostasis
 Clot retraction – fibrin threads pull the edges of
the break in the vessel together.
 Note: vitamin K (produced in the colon)
stimulates the production of prothrombin by the
liver.
 Embolus – blood clot that moves
 Thrombus – stationary blood clot

19. Blood Types
 ABO Blood Group
 4 blood types – A, B, AB, O
 Types are identified by antigens located on the
RBC surface.
 Antigens – protein substances that can stimulate
the body to make antibodies.
 Antibody – proteins made by the body in response
to stimulation by an antigen – causes clumping or
agglutination in the case of RBCs.

20. Blood Types
 ABO group
 A person with Type A blood has A antigens on
their RBC and a person with Type B blood has B
antigens. What antigens does a person with
type AB blood have? type O?
 Natural antibodies are also present in the
plasma: A person with type A blood has anti-B
antibodies and a person with type B blood has
anti A antibodies. What antibodies do people
with type AB or type O blood have?

21. Blood Types
 Typing and cross-matching – process by
which blood type is identified and donor
blood is tested for possible transfusion.
 Transfusion:
 Type O is a “universal donor”, i.e.can give blood
to anyone.
 Type AB is the “universal recipient”, i.e. can
receive blood from anyone.

22. Blood Types
 Transfusion
 Type A can receive type A or type O blood
 Type B can receive type B or type O blood
 Type AB can receive type B, A, AB, or O
 Type O can receive type ??? Blood.

23. Blood Types
 Rh factor – another antigen which may be
present (Rh +) or absent (Rh -) on RBCs.
 Rh negative (-) do not have natural antibodies to
the Rh antigen. If they receive blood that is Rh
positive (+) antibodies form but not a problem.
The second exposure can produce a transfusion
reaction (hemolysis and possible kidney
damage).

24. Blood Types
 Rh factor
 People with Rh negative blood should receive Rh
negative blood.
 ??? What blood type is the “real Universal
donor”?