Introduction to Epithelial and Glands


Glands

Slide 22 - simple, unbranched straight tubular glands

Large intestine typically has simple, columnar epithelium with goblet cells, arranged into simple straight tubular glands. The glands are oriented in the same direction, even if that direction is at an angle to the plane of sectioning. The slide has a few areas with straight glands running the depth of the epithelial (mucosal) layer.



Slide 146 - Simple, Columnar Epithelium, Unicellular Goblet Cells and Simple, Branched Coiled Tubular Glands

This is intestine, and has a simple, columnar epithelium with goblet cells and a brush (or striated) border. Review the classical shape of a goblet cell. (Remember to look for an ideal presentation of epithelium.)


Then, at low power, examine the glands that are located below the epithelium. Their product is semi-mucous, and they have a typical branched, coiled tubular shape, with one generation of ducts ... thus a simple (not compound) design.

Of immunological interest, you may observe some dark blue spheres within the epithelium. These are lymphocytes, t-cells to be precise. They are sentinels for antigens.



Slide 66 Stratified Squamous Epithelium, with simple, branched alveolar (acinar) holocrine sebaceous (oil) glands, and simple, unbranched coiled tubular apocrine sweat glands

Stratified squamous epithelium covering the mammalian body typically has two major types of glands. Sweat glands moisten and cool; oil glands soften and prevent desiccation. The glands on this slide of goat skin are large. You may not need to use 40X. Use your atlas to find examples of:


  • sebaceous glands, with holocrine production of sebum
  • coiled tubular sweat glands that run deeper than the other epithelial components
  • myoepithelial cells at the bases of the secreting cells
  • sebaceous glands emptying into shafts of hair follicles.



Slide 147 - Feline Pancreas - compound, branched, tubulo-alveolar, serous gland

Here's the big kahuna - a classical example of a really complex gland.

Take a look for:
  1. sections through ducts of different sizes (hence ... many generations of ducts)
  2. tubulo-alveolar (tubulo-acinar) endings that branch
  3. classical serous appearance to the secretory cells, including:
    1. spherical, heterochromatic nuclei located on the basal side of centre
    2. a blue-staining base, indicative of high rough endoplasmic reticulum content
    3. a pink-orange apical end, filled with eosinophilic granules
    4. small ducts around the secretory units, and
    5. (apparent at low magnification and by naked eye) a lobular design.



Optional Quiz Slide - Slide 8

On this slide you should be able to locate portions of two tubular organs (one is considerably thicker than the other), and two solid structures on the sides.

Looking first at the thick tubular organ, what kind of epithelium lines its lumen?

Classify the glands that empty into this lumen.


Turning next to the solid structures on the sides, you'll see that it is composed of a series of small follicles, each lined by an epithelium. Classify this epithelium.

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