The protein, water and salts forced out from between the fibrin strands by centrifugation is known as serum. Estimate the Hct for the microhematocrit shown on the lower right. The Hct varies with age and sex. All blood cells appear to originate from a common progenitor cell or pluripotent. Purported stem cells can be recogized only by immunologic means as morphologically they resemble immature lymphocytes.
Stem cells are self-replicating in that only one of the daughter cells differentiates.
The other remains a stem cell. Thus the number of stem cells remains constant. Thus the number of stem cells remains constant. Most of the early hematopoietic development and maturation takes place in the bone marrow. Hematopoiesis is found in only certain bones of which the major sites are the vertebra, sternum, pelvis, ribs, skull, scapula,and proximal long bones.