Kamis, 05 April 2012

Cells


Fibrocytes—Fibroblasts

In connective tissue sections, the nonmotile (fixed) fibrocytes look like thin, spindle-shaped elements. However, their true shape can be brought out in thin whole-mount preparations. Fibrocytes are sometimes rounded, sometimes elongated, flattened cells with membranous or thorn-like processes 1 . The cell processes often touch each other and form aweb. Their large, mostly oval nuclei feature a delicate chromatin structure (not visible in this preparation). Here, the nuclei appear homogeneous . Fibroblasts biosynthesize all components of the fibers and the extracellular matrix (ground substances). Fibrocytes are fibroblasts that showmuch lower rates of biosynthetic activity.

1 Fibrocytes with cytoplasmic processes
2 Nuclei from free connective tissue cells
Stain: Gomori silver impregnation, modified; magnification: × 650


Purkinje Cells—Cerebellar Cortex

Pear-shaped Purkinje cells, which are about 50–70μm high and 30–35μm wide (cell soma, perikaryon) 2 , send out 2–3μm thick dendrites that branch out like trellis trees. These delicate trees reach up to the cortical surface, extending their fine branches espalier-like in only one plane. The axon (efference) 1 spans the distance between the basal axon hillock and the cerebellar cortex. The elaborate branching can only be seen using metal impregnation
1 Axon
2 Perikaryon
Stain: Golgi silver impregnation; magnification: × 50




Oocyte

Oocyte from a sea urchin ovary. Large, heavily stained nucleolus 2 inside a loosely structured nucleus 1 . The finely granulated cytoplasm contains yolk materials. Cell organelles are not visible 

1 Nucleus
2 Nucleolus
Stain: azan; magnification: × 150





Vegetative Ganglion Cell

Large vegetative ganglion cell from the Auerbach plexus (plexus myentericus) from cat duodenum. A collateral branches from the upward extending axon. The downward-pointing cell processes are dendrites. Note the large nucleus

Stain: Cauna silver impregnation; magnification: × 650



Kuehnel, Color Atlas of Cytology, Histology, and Microscopic Anatomy © 2003 Thieme

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