Essentials of Anatomy and Physiology

The Integumentary System 103

FOR FURTHER THOUGHT

1. The epidermis has no capillaries of its own; the
   stratum corneum is made of dead cells and doesn’t
   need a blood supply at all. Explain why the epider-
   mis is affected by a decubitus ulcer. Name another
   group of people, besides hospital or nursing home
   patients, that is especially susceptible to developing
   pressure ulcers.


2. Going out in the sun stimulates quite a bit of activ-
   ity in the skin, especially on a hot summer day.
   Describe what is happening in the skin in response
   to sunlight.


3. Ringworm is a skin condition characterized by

scaly red patches, often circular or oval in shape. It

is not caused by a worm, but rather by certain

fungi. What is the food of these fungi; that is, what

are they digesting?

4. There are several kinds of cells in the epidermis.
   Which cells exert their functions when they are
   dead? Which cells must be living in order to func-
   tion?


5. Wearing a hat in winter is a good idea. What hap-
   pens to the arterioles in the dermis in a cold envi-
   ronment? How does this affect heat loss? Is the
   head an exception? Explain.