130 Chapter 6
Career
FOCUS
These are careers that are available to individuals interested in the integumentary system:●● Cosmetologists have careers as makeup artists and hairstylists with positions in
television, the cinema, and local hair salons.^
●● Dermatologists are physicians who specialize in the diseases and disorders of the
skin.^
●● Allergists are physicians who specialize in the inflammatory responses of the skin and
reactions of the immune system.^
●● Plastic surgeons are physicians who specialize in cosmetic surgery to correct
birthdefects and to counteract the effects of aging.^
●● Nurses can also have careers that specialize in skin care.When external temperatures increase, blood -vessels in
the dermis dilate to bring more blood flow to the surface of
the body from deeper tissue beneath. In the -dermis of the
skin, this blood with its warm temperature can be lost by
either radiation, convection, or conduc-tion as applicable.
When we sweat, the water in sweat evaporates, which
requires energy and thus carries away heat to reduce body
temperature.
When external temperatures decrease, the first
-response is for blood vessels in the dermis to dilate to
bring heat to the surface to warm our extremities. Light-
skinned individuals will have rosy cheeks when they first
go out in the cold. Excessive exposure to the cold cannot be
main-tained for long, so blood vessels then constrict to
bring the heat inside to preserve the vital organs of the
body. Frost-bite occurs when the skin of the extremities no
longer gets a blood supply due to the maintained
constriction of the blood vessels in the dermis to conserve
heat. The tissues in the tips of these extremities die and turn
black.
Secretion
The skin produces two secretions: sebum and sweat.
Sebum- is secreted by the sebaceous glands. In addition to
imparting a cosmetic gloss to our skin and moisturiz-ing
our skin, sebum has both antifungal and antibacte-rial
properties. It helps prevent infection and maintains the
texture and integrity of the skin. Sweat is produced by the
sweat glands and is essential in the cooling pro-cess of the
body. Sweat also contains waste products such as urea,
ammonia, and uric acid and so can also be considered an
excretion. A secretion is something ben-eficial, whereas an
excretion is something the body does not need and could be
harmful.
The skin is actively involved in the production of
vitamin D. Exposure to the ultraviolet rays of the sun
stimulates our skin to produce a precursor molecule of
vitamin D that then goes to the liver and kidneys to be-
come mature vitamin D. Vitamin D is necessary for our
bodies because it stimulates the intake of calcium and
phosphorus in our intestines. Calcium is necessary for
muscle contraction and bone development. Phos-phorus is
an essential part of adenosine triphosphate. Because we live
indoors, and in colder climates wear heavy clothing, we
sometimes do not get enough expo-sure to the sun to
adequately produce enough vitamin D. We also should
ingest vitamin D through our diets. Good sources of
vitamin D are milk, other dairy prod-ucts, and fish oils.Body Systems
Working Together To
Maintain Homeostasis:^
The Integumentary SystemSkeletal System
●● Vitamin D manufactured by the skin helps provide
calcium for strong bones.
Muscular System
●● Vitamin D helps provide calcium for muscle
contraction.^
●● Facial muscles produce facial expressions of body
language.^
●● Shivering helps control body temperature by warm-
ing the body.