Clinical note: Sebaceous glands become much more active after puberty and can become affected causing acne vulgaris. The increased build-up of sebum and dead cells leads to blocked ducts/hair follicles resulting in small white lesions (comedones) that can be sites of bacterial infection. The disease is normally self-limiting, but comedones can become sites of bacterial infections. Sometimes there is marked scaring left in the wake of the inflammation.

On these two slides of H&E and trichrome stained skin (sample 1, sample 2) identify:

• Secretory portions and darker-staining ducts of merocrine (“eccrine”) sweat glands.
• Look for myoepithelial cells surrounding the secretory units.
• In the ducts, note the unusual stratified cuboidal epithelium lining the ducts and the lack of myoepithelial cells.

Examine the next two slides for apocrine sweat glands (sample 1, sample 2).

• Compare the lumen size and overall histological appearance of apocrine sweat glands to the more common merocrine/eccrine sweat glands.

Try this short  self-assessment quiz to see what you've learned.

Next is the cartilage and bone.