BLOOD
Learning Outcomes:
C6 - Describe the components of blood:
 Describe the shape, function and origin of red
blood cells, white blood cells, and platelets
 List the major components of plasma
 Explain the role of antigens and antibodies
Functions of Blood
Why do we need blood?
 Transport
 O2 and CO2, nutrients,
wastes, hormones
 Protection
 Seek and destroy pathogens,
provide immunity
 Regulation
 Temperature, body chemistry
Components of Blood
Components of Blood
Plasma
 Fluid containing dissolved substances and plasma proteins
Formed elements - the “solids”
 Red blood cells
 White blood cells (several types)
 Platelets
Fig. 13.10a
Fig. 13.10b
Fig. 13.10c
Plasma
 The fluid portion of blood
 Contains water, salts, nutrients, dissolved gases,
plasma proteins, wastes
 Maintains correct pH, blood volume, and
chemical composition of blood
Plasma Protein Functions
 Immunity (antibodies)
 Messengers (hormones)
 Clotting factors (prothrombin, fibrinogen)
 Albumin - maintains osmotic pressure and
transports substances
Formed Elements
Red Blood Cells
 a.k.a. erythrocytes
 Live 120 days; made in
the red bone marrow
 Function is transport
of O2 and CO2
 Disc, shaped, with no
nucleus
What advantage might this
shape have?
Hemoglobin
 A protein found in red
blood cells
 4 polypeptides and a
heme (iron) group
 Oxygen binds to the
heme portion
Fig. 13.11
White Blood Cells
 A.k.a. leukocytes
 Contain nuclei
 Main function is fighting disease and infection
 Several different types, with specific functions
Monocytes
 Become macrophages,
the largest w.b.c’s
 Phagocytic - engulf
and destroy bacteria
and viruses
 Video of white blood
cell attacking a
bacterium
Fig. 13.12
Neutrophils
 Granular in appearance
 phagocytic
Lymphocytes
 B lymphocytes - formed in the bone
marrow
 Produce antibodies – specific
proteins that bind to antigens of
invaders
 T lymphocytes - made in bone
marrow, mature in the thymus gland
 Attack foreign cells directly using
various mechanisms
Platelets and Blood Clotting
 Platelets are fragments of larger cells
 Work with plasma proteins to make a clot to
repair damaged blood vessels
 Blood clotting prevents excess blood loss in case
of injury
The Clotting Process
 Platelets collect at injury site and initiate the
clotting process
 Several proteins are involved – as enzymes, and as
part of the clot
3
Why does this process have to go through all these steps?
Why can’t fibrin be present in the blood all the time?
Stem Cells
 Undifferentiated cells,
found in the
developing fetus and
some adult tissues
 Mature to become all
different types of cells
 All types of blood cells
originate from stem
cells in bone marrow
Fig. 13.14
Stem Cell Story Video
 http://www.eurostemcell.org/films/a-stem-cell-
story/English
 http://www.youtube.com/watch?v=2-3J6JGN-_Y