What is the normal bone marrow cellularity in the population ...

[jazziefee]

What is the normal bone marrow cellularity in the population older than 65 years?
 
  a. 90
  b. 70
  c. 50
  d. 30

Question 2

Why is there a relative lymphocytosis in a 2 year old?
 
  a. An absolute neutropenia occurs.
  b. The absolute number of lymphocytes is increased as the immune system develops.
  c. A greater proportion of neutrophils are marginated.
  d. Fewer lymphocytes are marginated.

[mathjasmine]

Answer to Question 1

ANS: D
Bone marrow cellularity decreases in the older population and is approximately 30. That of a young adult is 50. This change may be caused by an increase in the volume of spongy tissue in the bone, as well as an increase in fat, rather than an actual decrease in hematopoietic tissue.

Answer to Question 2

ANS: B
An absolute increase in lymphocytes occurs, presumably because the immune system is developing as more antigens are encountered; this increases the absolute number of lymphocytes, as well as the relative percent. The number of marginated neutrophils is not increased; lymphocytes do not marginate.