Chapter 2 Lesson 2

Keratin is an important skin pigment that protects against ultraviolet light.

False

Lipid-soluble substances such as O2, CO2, and Vitamins A, D, E, and K cannot penetrate the skin.

False

When an individual is exposed to extremely low air temperatures, the capillaries of the skin will dilate so that the blood will flush into skin capillary beds and heat will be dissipated.

False

Which of the following is not one of the functions of the skin?

Gives the body its overall shape, loss of this function can be seen with the dropping of skin with age.

Water loss through the epidermis could case a serious threat to health and well-being.

Glycolipids that are secreted by keratinocytes into extracellular spaces.

In addition to protection (physical and chemical barrier), the skin serves other functions.

It converts modified epidermal cholesterol to a vitamin D precursor import to calcium metabolism.

Which of the following is NOT true about the skin?

Our primary way of eliminating nitrogen-containing wastes is though the skin.

Which of the following statements indicates the way in which the body's natural defenses protect the skin from the effects of the UV damage?

Prolonged exposure to the sun induces melanin dispersion, which in turn acts as a natural sunscreen.

Which of the following examples listed below illustrates homeostasis maintained by a negative feedback?

Release of sweat by eccrine glands in response to heat.

A light skinned person who is very cold may have a pale appearance.

The person's blood vessels in the dermis have undergone vasoconstriction (narrowing).

DNA helps protect skin cells from damage by absorbing UV radiation and dissipating the energy as heat.

True

The apocrine sweat glands are not the primary gland involved in thermoregulation.

True

The pinkish hue of healthy individuals with fair skin is the result of the crimson color of oxygenated hemoglobin circulating in the dermal capillaries and reflecting through the dermis.

True

Melanocytes and keratinocytes work together in protecting the skin from UV damage when keratinocytes _____________.

accumulate the melanin granules on their superficial portion, forming a UV-blocking pigment layer

A lightskinned person may appear pink when they become over heated.

the blook cessels of the dermis have undergone vasodilation, bringing a greater volume of blood to the skin