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FUNCTIONS OF BLOOD
 Transportation-
O2 and CO2,
nutrients, waste, hormones
 Regulation- pH (buffers), heat,
osmotic pressure
 Protection- clotting, immune system
 Connective
tissue: has no fibers
 The only fluid tissue in the body
 Composed of formed elements
suspended in a nonliving fluid
called plasma
BLOOD CHARACTERISTICS
Can be separated into layers with centrifuge
 Heavier, thicker, more viscous
than H2O
(5x)
 Temperature of 100.4 F
 pH of 7.4
 8% body weight
 5-6 liters (1.5 gallons) in males
 4-5 liters (1.2 gallons) in females


Plasma: Liquid matrix (ECF) (55% of total
blood volume)
 Over 90% water
 Over 100 substances dissolved - Figure
10.1
 Proteins
(most abundant)
 Nutrients
 Lipids
 Electrolytes
 Respiratory gases
 Wastes
 Homeostatic
mechanisms keep fairly constant
Erythrocytes

RBCs (45% blood volume)
 carry
O2
 No nucleus or organelles
 No mitosis/ metabolism
 Outnumber white blood cells 1,000 to 1
 5 million RBC/mm3
 Hemoglobin (4 protein complex)- 33% volume
 Responsible
for color of blood
 1 RBC contains~250 million hemoglobin molecules
Erythrocytes

RBCs (45% blood volume)
 Antigens
on membrane determine ABO blood
type and Rh factor
 Worn down RBCs destroyed in spleen and liver
(macrophages)- 120 day life span
 Too few RBCs or hemoglobin= anemia
 Not enough O2 intake= hypoxia
 Leukocytes
(WBCs): 1% of blood volume
Have nucleus
Defend against bacteria, viruses,
parasites, tumor cells
Separated into granulocytes (3 types)
and agranulocytes (2 types)
(Table
10.2)
GRANULOCYTES
Neutrophils (40-70%of WBCs)- phagocytic
 (small granules)


Eosinophils (1-4%)- kill parasites/ controls
inflammation/ release histaminases (fight allergic
reaction)

Basophils (<1%)- release heparin, histamine,
serotonin
AGRANULOCYTES

Monocytes (4-8%)- phagocytic (large)
Lymphocytes (20-45%)- provide immunity
 B and T cells produce antibodies

 Thrombocytes
(platelets)
Fragments of megakaryocytes
Repair slightly damaged vessels
Promote clotting
link
Occurs in red
bone marrow
 100 billion cells
produced daily
 All arise from
hemocytoblast
(stem cell)

NORMAL BONE MARROW
nucleated
erythroid
precursors
eosinophil
normal megakaryocyte
FORMATION OF RED BLOOD CELLS
Process takes 3-5 days
 Rate of production controlled by erythropoietin
(hormone)

FORMATION OF WHITE BLOOD CELLS AND
PLATELETS

Stimulated by hormones
 Released
bacteria)
by chemical signals (inflammation,
HEMOSTASIS: STOPPAGE OF BLEEDING

Three phases
a)
b)
c)
Vascular spasms
Platelet plug formation
Coagulation

Vascular spasms—smooth muscle contracts

Vasoconstriction decreases blood loss

Platelet plug formation– exposed collagen fibers
cause platelets to adhere to damaged area
 Platelets cause nearby platelets to become
sticky and form plug

Coagulation—at the same time
Formation
of mesh of fibrin strands trap RBCs to
make clot
 Process
normally takes 3-6 minutes
HUMAN BLOOD GROUPS
Due to proteins (antigens) on plasma
membranes of RBCs
 Antigens of one type are recognized as foreign
by antibodies of another
 Antibodies bind to foreign RBCs and cause
agglutination (clumping) and rupture
(hemolysis)
 ABO and Rh blood groups are most important

BLOOD TRANSFUSION
Blood
Group
O
A
B
AB
•
Prevalence
Blood Rec.
****
***
**
*
Only O
O or A
O or B
All
If the wrong blood type is used the person’s own
immune system immediately attacks the donor’s
blood and causes clots and RBC destruction that
can lead to total kidney failure and death.
NO AGGLUTINATION REACTION
•
A person with blood type A can receive
blood from a donor with blood type A.
–
The anti-B antibodies in the recipient do not combine
with the type A antigens on the red blood cells of the
donor.
AGGLUTINATION REACTION

A person with blood type B cannot receive
blood from a donor with blood type A.

The anti-A antibodies in the recipient will combine
with the type B antigens on the red blood cells of the
donor.
Rh BLOOD TYPE

Rh+: have Rh antigen and no antibodies

Rh-: have no antigens and no antibodies

Rh-negative people will develop antibodies to the Rh antigen
if they are exposed to the Rh-positive blood

If a Rh-negative woman becomes pregnant with a Rhpositive fetus she may make antibodies to the fetus’ RBCs

This can be prevented with RhoGAM
HEMOLYTIC DISEASE OF THE NEWBORN (HDN)
HDN is the most common problem with Rh incompatibility.
AGGLUTINATION
REACTIONS