Skin Appendages -- epidermal derivatives such as hair follicles, glands, etc. whose distribution, arrangement, and structural details vary greatly in skin on different parts of the body.

Examine several hair follicles cut transversely on slides 17 and 36.

In the hair shaft itself, identify if possible the

• Medulla,
• Cortex, and
• Cuticle (Fig. 18-13).
  • Not all layers may be evident, depending on the plane of section.
• Identify the internal and external root sheathes of the follicle.

Examine hair follicles cut longitudinally on slide 67 and slide 51, and again identifying as many layers as possible. Identify

• Sebaceous glands (Fig. 18-15), pictured to the right, and
• Arrector pili muscle (Fig. 18-12) associated with hair follicles.

What type of muscle is the arrector pili muscle?

How do hairs, sebaceous glands, and arrector pili muscles contribute the functions of skin?

What is the mode of secretion of sebaceous glands and why do they stain poorly?

More on skin appendages.