1084 



GENERAL ANATOMY OR HISTOLOGY. 



flattened from mutual pressure, and are set upright on the surface on which they 

 are supported. Their protoplasm is always more or less reticulated, and fine 

 longitudinal striae may be seen in it. They possess a nucleus which is oval in 

 shape and contains an intranuclear network. 



This form of epithelium covers the mucous membrane of nearly the Avhole 

 gastro-intestinal tract and the glands of that part, the greater part of the 



FIG. 605. Spheroidal epithelium. 

 Magnified 250 times. 



FIG. 600. Ciliated epithelium from the human 

 trachea. Magnified 350 times, a. Innermost 

 layers of the elastic longitudinal fibres, b. 

 Homogeneous innermost layer of the mucous 

 membrane, c. Deepest round cells, rf. Middle 

 elongated cells, e. Superficial cells, bearing cilia. 



urethra, the vas deferens, the prostate, Cowper's glands, Bartholini's glands, and 

 a portion of the uterine mucous membrane. In a modified form it also covers 

 the ovary. 



G-oblet- or chalice-cells are a modification of the columnar cell. They appear 

 to be formed by an alteration in shape of the columnar epithelium (ciliated or 

 otherwise) consequent on the formation of granules which consist of a substance 

 called mucigen in the interior of the cell. This distends the upper part of the cell, 

 while the nucleus is pressed down toward its deep part, until the cell bursts and 

 the mucus is discharged on to the surface of the mucous membrane as shown in 

 Fig. 604, the cell then assuming the shape of an open cup or chalice. 



The glandular or spheroidal epithelium (Fig. 605) is composed of spheroidal or 

 polyhedral cells, but the cells may be columnar or cubical in shape in some situ- 



FIG. 607. Epithelial cells from the oral cavity of man. Magnified 350 times, a. Large, b. Middle sized. 

 c. The same with two nuclei. 



ations. Like other forms of epithelial cells, the protoplasm is a fine reticulum, 

 which gives to the cell the appearance of granulation. They are found in the 

 terminal recesses of secreting glands, and the protoplasm of the cells usually 

 contains the materials which the cells secrete. 



Ciliated epithelium (Fig. 606) may be of any of the preceding forms, but usually 

 inclines to the columnar shape. It is distinguished by the presence of minute 

 processes, which are direct prolongations of the cell-protoplasm, like hairs or eye- 



