Example tissues that exhibit a broad range of sizes, shapes, morphology, and staining characteristics of cells and nuclei.

Blood Cells

Blood Smear - blood consists of 99% red blood cells and 1% white blood cells.

• Red blood cells are biconcave discs without a nucleus and have a diameter of ∼7.5 to 8.0 µm.
• They do not stain with hematoxylin.
• The red color (eosinophilia) is due to the high concentration of the protein hemoglobin in these cells.
• White Blood Cells - have nuclei of various shapes, staining patterns and vary in size (#1, #2, #3) from ∼10 to 25 µm.

Trachea

Trachea - contains examples of basophilia (stains with hematoxylin) and acidophilia (stains with eosin).

• Acidophilia (or eosinophilia) can be seen within cells such as red blood cells and duct cells. Eosin also stains the major extracellular protein, the connective tissue protein collagen.
• Basophilia can be seen within and outside cells. Hematoxylin stains DNA and RNA within cells. It also stains other negatively charged molecules. For example, the sulphated glycoproteins found in mucus and sulphated polysaccharides found in the extracellular matrix of cartilage.
• This section contains many examples of nuclear size, shape (round, spindle, lenticular) and staining intensity (euchromatic or heterochromatic).

Small Intestine

Small Intestine - In most places the surface epithelium is detached from the underlying supportive tissue.

• The surface eithelium is composed of polarized, column shaped cells with an oval nucleus found in the basal portion of these cells.
• Polarized cells have a basal surface that rests on supportive connective tissue and an apical free surface that faces the opposite side.
• The free surface always faces a lumen, such as, the interior of the gut or a duct.
• The cells in the lamina propria are found beneath the epithelial surface cells and are not polarized.
• Most cells have euchromatic nuclei.
• Many cells have eccentric nuclei (nuclei located not a the center of the cell).
• Smooth muscle and collagen.
• Smooth muscle cells are arranged in parallel bundles and have long spindle shaped euchromatic nuclei. These pink cells are seen in cross section in the lower left and in cross section in the upper right. Note the appearance of the nuclei in longitudinal and cross sections.
• The brighter red staining material is collagen and is extracellular. The cells interspersed among the collagen are fibroblasts with heterochromatic nuclei.