Introduction to Integument


Lips, Noses, and Wool

Slide 165 - Feline Lip

Lips have two sides. The outside is hairy, with a regular complement of sebaceous glands, sweat glands, thin, stratified squamous epidermis, and keratinized outer epidermis. On the inside is the mucous membrane of the oral cavity. This is also stratified, squamous epithelium with a dermis layer beneath, but there are no hairs or related glands.

Note that the hairs of the outer integument gather in clusters, with several secondary or insulating hairs associated with each primary or guard hair. You may also observe fibers of skeletal muscle in the region where a hypodermis should be located, as well as throughout the dermis. This unusual feature of integument is due to the high degree of flexibility required in the use of lips. The individual fibers of skeletal muscle are not erector pilus muscles, however.




Slide 45 - Canine Nose

Take a close look at the slide with your naked eyes, and you'll see the thicker epidermis of the hairless region on the true nose, as compared to the regular hairy skin on the sides. The nose is endowed with a very thick epidermis, and even thicker dermis which blends into the supporting cartilage rather than a hypodermis.




Since this part of the body may be considered an extension of the lip shown above, there is still that unusual feature, numerous skeletal muscle fibers throughout the hairy skin portion of this slide.

Carefully examine the skin at the base of the nose, then determine, does this canine skin have sweat glands?


Slide 65 - Ovine Wool

This is your mystery slide for the day. Does wooly skin have:

a) hollow or solid hairs (wool)? Are they more like primary or secondary fur?

b) sweat glands?

c) sebaceous glands?

d) thick (> 10 living cells thick) or thin epidermis?
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