Since macrophages are sometimes associated with reticular connective tissue and since they often line blood sinusoids, macrophages are generally considered to form the reticulo-endothelial system. The nucleus is small, roughly spherical and pyknotic. Plasma Cells - are smaller than mast cells. There is a modest amount of cytoplasm and an eccentrically placed, spherical nucleus. Look for clock-face nuclear chromatin packing.
Lymphocytes are cells that have a dense nucleus and a small amount of cytoplasm.
Like plasma cells they originate from the blood stream but are often found in loose connective tissue. It has a honeycomb appearance and each large space represents the interior of a fat cell, which in life, was one large droplet of fat. The nucleus is pushed to the edge of the cell. Since lipids are soluble in our embedding chemicals, the fat is removed in this section. This is a whole mount, not a section.