Ch 20: The Blood
Discuss the composition of blood including the
functions of the various components
Explain the anatomy and functions of the red blood cells,
including a description of blood typing
Discuss the types of white blood cells found in the blood
and give the functions of each
Give a brief accounting of the platelets
Review hemopoiesis, including RBC and
leukocyte formation
Functions of Blood

Distribution - nutrients, wastes,
hormones, gases, etc.

Self-sealing – hemostasis

Disease/ infection fighting
Blood = connective tissue
extracellular
matrix:
Plasma
specialized cells:
(= Formed elements)
RBCs
WBCs
color ?
volume ?
Platelets
Plasma Composition
Transports organic and
inorganic molecules,
formed elements, and heat



Water
92%
Plasma proteins 7%
Other solutes
1%
Plasma Proteins

Albumin (60%) Major contributor to osmotic
concentration of plasma. Transport of lipids
and steroid hormones

Globulins (35%) Transport ions, hormones,
lipids; immune function

Fibrinogen (4%) Essential component of
clotting system (conversion to insoluble
fibrin)

Regulatory proteins (< 1%) ????
Other Solutes
 Electrolytes:
Normal extracellular
fluid ion composition (????)
 Organic
nutrients: glucose, FA,
AA
 Organic
wastes: urea, bilirubin
Difference between Plasma and Interstitial Fluid :
Plasma has more:


Dissolved O2
O2 diffuses out into tissue
Dissolved proteins (too big to cross caps.)
» Albumins
» Globulins
–  globulins
–  and  globulins
» Fibrinogen
Similar concentration: Salts & small molecules
Difference between
plasma and serum?
serum = plasma -
. . . . 2 more things:
Most plasma proteins are made in liver.
Exception: ?
Lipoproteins = particles containing
lipids (cholesterol & triglycerids) and
proteins (albumins & globulins)
Formed Elements
Red and White
Blood Cells
Platelets
Platelets
 WBCs


RBCs
.1%
99.9%
Formed Elements cont.
Why white blood cells???
RBCs = Erythrocytes
Measured by hematocrit or PCV
Most abundant blood cell: 1000
RBCs/1 WBC
Contain hemoglobin, carry O2
Very regular shape - biconcave discs
Anucleate: Lifespan ~ 120 days
replacement rate ~ 3 mio RBCs / sec
Structure of Hemoglobin (Hb)

Fe ion
in heme
group
reversibly
binds O2
How many oxygen
molecules can 1
Hb molecule
carry?

ABO & Rh Blood

Types
Blood groups (types) based on
specific RBC surface antigens (=
proteins)
blood type ?

> 30 common varieties of antigens
known. Most important ABO & Rh
ABO Blood typing:
4 combinations possible
A surface antigen = blood type A
 B surface antigen = blood type B
 both surface antigens = type AB
 neither surface antigen = type O

Rh surface antigen = + blood type
 no Rh antigen = negative blood type

. . . 2 - 8 months after birth:
Anti-A and anti-B antibodies can be
formed in plasma !
normally NO
anti Rh present
Transfusion Reaction
Transfusion of incompatible blood can be fatal!
Universal Donor vs.
Universal Recipient
Only for emergencies - must be
given slowly !
Clinical Brief
Anemia: p. 536
Reduced oxygen carrying ability of blood.
Causes??
Polycythemia:
Erythrocytosis: excessive increase in
RBCs
Polycythemia vera:
Blood Doping: p. 545
Via direct transfusion, or
EPO use
WBCs = Leukocytes
Quantity and type determined
by differential WBC count
Circulating WBCs are only a
small fraction of total WBCs.
Most are located in ?
Diapedesis
Chemotaxis
Granulocytes and
Agranulocytes
Neutrophil (= PMN)
Up to ~ 70% (~ 2/3) of circulating WBCs
Cytoplasm packed with pale granules containing
lysosomal enzymes
phagocytic
Eosinophil
~ 2% - 4% of circulating WBCs
Granules stain with eosin
Increased in allergies and parasitic infections
Basophil

< 1% of circulating WBCs

Granules stain with basic dyes and contain histamine

Discharge of histamine promotes inflammation at site
of injury (Similar to mast cells)
Monocyte



~ 2% - 8% of circulating WBCs
Large kidney shaped nucleus
In tissue called Macrophage
Lymphocytes




~ 20% - 30% of circulating WBCs
Relatively small (slightly larger than RBCs)
Large round nucleus
B, T, NK
Platelets = Thrombocytes
Cell fragments of Megakaryocytes
(~ 4,000 thrombocytes per Megakaryocyte)
 ~ 160 m
Lifespan ~ 12 days
involved in blood
clotting
Abnormal Blood Cell Counts
Leukopenia < 2,500/ L (normal 6000 – 9000)
Leukocytosis > 30,000/ L
Thrombocytopenia: < 80,000/ L (normal ~ 350,000)
Thrombocytosis: > 1,000,000/ L
Also
Lymphopenia vs. _____________
_________vs. Neutrophilia
Hemopoiesis = Blood Cell Formation
Hemocytoblasts: One type of stem cell for all blood cells
. . . then differentiation
into 4 types of
progenitor stem cells:
Erythroblast
Myeloblast
Monoblast
Lymphoblast
In red bone marrow
Fig 20.8