MORPHOLOGY OF BLOOD CELLS
Section I. GENERAL INFORMATION
BASIC CONCEPTS OF CELL MORPHOLOGY
a. In this lesson, all normal and most commonly seen abnormal blood cells are
morphologically described. Although general rules for identification are given along with
representative photographs and drawings, it is important to realize that no biological
entity fits the guidelines precisely.
b. The present classification of blood cells is man's attempt at identifying stages
of maturation by assigning artificial steps to a continuing process. The process is a
smooth, continuing one, and therefore no one cell ever precisely fits the criteria for a
specific stage. These stages are artificial classifications that exist to simplify
GENERAL RULES OF CELL IDENTIFICATION
Certain general rules are applied to all cell maturation (hemopoiesis) either in the
erythrocyte, leukocyte, thrombocyte, or plasmocyte series. Although these rules are
broken by individual cells, they are an aid to classifying cells.
a. Immature cells are larger than mature cells and become smaller as they
b. The relative and absolute size of the nucleus decreases as the cell matures.
In some cell series the nucleus disappears.
c. The cytoplasm in an immature cell is quite blue in color and lightens as the
d. The young nucleus is reddish and becomes bluer as the cell ages.
e. Nuclear chromatin is fine and lacy (lacelike) in the immature cell It becomes
coarse and clumped in the more mature cells.
f. If there is doubt in the identity of a cell, classify to the more mature form.
Section II. ERYTHROCYTES
a. In the normal development and maturation (erythropoiesis) of the erythrocytic
series, the red blood cell undergoes a graduation of morphological changes. This cell