Globulins are a class of protein that comprise 36 of

liver and constitutes 60% of the total protein content of the blood. Globulins are a class of
protein that comprise 36% of plasma proteins (they function in lipid transport, as steroid
hormones, and in blood clotting). Fibrinogen is another protein synthesized in the liver, and is
essential to formation of blood clots.
With respect to its cellular constituents, the proportion of blood volume that is composed
of erythrocytes is termed the hematocrit . The cellular constituents of the blood are produced
within bone marrow. The most abundant cell type are the erythrocytes (45% of blood volume).
These red blood cells contain large quantities of hemoglobin . Hemoglobin is essential for
transport of oxygen and carbon dioxide in the blood. These cells no longer function like other
cells since they lack nuclei, mitochondria, and ribosomes. They have a relatively short lifespan
(120 days) and are stimulated to proliferate by erythropoietin. The remainder of the cellular
components of blood include leukocytes and platelets . Leukocytes function to defend the body
against microorganisms and other foreign materials. Unlike red blood cells, these cells are not
restricted to the circulation and can be found in most tissues. Platelets are important in blood
clots. They are derived as cellular fragments from megakaryocytes.
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2) Oxygen and carbon dioxide are poorly soluble in plasma so they require erythrocytes for their
transport in blood. Describe how erythrocytes transport these gases.
ion.
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3) Erythrocytes have no nucleus or organelles. Therefore, the lifespan is short. Describe the
lifecycle of erythrocytes.