Read the section on skin (pp. 152-157).

• You should learn the names of the five visible layers of epidermis of thick skin and the four visible layers of the epidermis in thin skin. That's something I usually ask on exams.
  • In my opinion, the epidermal layers are better seen on Martini Fig. 5-4 than on Marieb Fig. 5.2. One note, though: the Martini figure uses an alternate name for the strata basale and spinosum called the stratum germinativum. (You don't need to learn that, but it sometimes shows up in some books.)
• You should know what process occurs in the stratum basale that makes it important.
• Two of the four major epidermal cell types that you should know are the keratinocytes and the melanocytes. Know what these cells produce and the importance of these products.
• You should know the names of the two layers of the dermis.
• You should know the tissue types found in the following skin layers:
  • Epidermis = stratified squamous epithelium
  • Dermis (papillary layer) = areolar connective tissue
  • Dermis (reticular layer) = dense irregular connective tissue
  • Hypodermis = mostly adipose tissue
• See this hand-drawn cross-section of skin that I draw on the board in class.
• See animation – Skin Regions
• See Art-Labeling Activity for Marieb Fig. 5.1

Read the section on skin color (p. 157).

• Know the three pigment molecules of the skin and their associated colors.
• Know the function of melanin. Why is melanin's location within the epidermis important to its function?
• Know that, of the three pigment molecules, only melanin is produced by the skin.
• I'm not interested in the disorders at the end of this section.

Read the section on sweat glands (p. 158).

• Be able to distinguish between eccrine sweat glands, apocrine sweat glands, and ceruminous glands. (Mammary glands usually get covered in the reproductive system, time permitting)
• All sweat glands are technically merocrine glands (see Marieb Fig. 4.5).

Read the section on sebaceous glands (p. 159).

• Sebaceous glands are holocrine glands (see Marieb Fig. 4.5).
• Know what sebum is.
• Sebaceous glands are usually hormonally controlled, which is why they often go haywire during puberty.

Read the section on hair and hair follicles (pp. 159-162; up until types and growth of hair).

• Know the three layers of a hair (medulla, cortex, and cuticle).
• Know the names of the root sheaths in the wall of the hair follicle, as well as the glassy membrane.
• Know that hair is composed of hard keratin.
• Know that hair grows from deep to superficial.
  • Laugh all you want but an unfortunate number of students get that question wrong every semester!
• Know that there are muscles and nerve endings associated with hair follicles.
  • The muscles (arrector pili) can make your hair stand up.
  • The nerve endings can detect when something lands on your skin.

Read the section on nails (p. 163).

• This is all you need to know:
  • Know these parts on Marieb Fig. 5.6: nail root, nail body, free edge, and the nail bed.
  • Know that the nail is made from hard keratin, which is structurally different from the "soft" keratin found in the skin. (Hair is also hard keratin.)
  • Know that nails grow from proximal to distal.

Read the section on the functions of the integumentary system (pp. 163-165).

• I consider this section to be fairly important.
• For each of the integumentary system's functions, you should be able to tell me which parts of the system are important in that function.
  • Example: Protection from pathogens.
    • Skin = barrier
    • Sebum = has antibacterial properties
    • Dermis = immune system cells roam through connective tissue and dispose of pathogens
  • Not all of the functions will use all of these players. (Only sweat glands function in excretion; only the skin has important metabolic functions, etc.)