Chapter 5
The Integumentary System
171
5
2.
Victims of third-degree burns demonstrate the loss of vital
functions performed by the skin. What are the two most
important problems encountered clinically with such patients?
Explain each in terms of the absence of skin.
3.
Telma, a 30-year-old resident of a mental hospital, has an
abnormal growth of hair on the dorsum of her right index
finger. Te orderly comments that she gnaws on that finger
continuously. What do you think is the relationship between
Telma’s gnawing activity and her hairy finger?
4.
A model is concerned about a new scar on her abdomen. She tells
her surgeon that there is practically no scar from the appendix
operation done when she was 16, but this new gallbladder scar
is “gross.” Her appendectomy scar is small, obliquely located on
the inferior abdominal surface, and very indistinct. By contrast,
the gallbladder scar is large, lumpy, and runs at right angles to the
central axis of the body trunk. Can you explain why the scars are
so different?
5.
Osteomalacia, a condition of soF bones, is prevalent in
Muslim countries that decree that their women wear the
burka, a garment that covers all but their eyes. What is the
cause and effect here?
6.
Mrs. Gaucher received second-degree burns on her abdomen
when she dropped a kettle of boiling water. She asked her doctor
(worriedly) if she would need a skin graF. What do you think he
told her?
22.
Why are there no skin cancers that originate from stratum
corneum cells?
23.
A man got his finger caught in a machine at the factory. Te
damage was less serious than expected, but the entire nail was
torn off his right index finger. Te parts lost were the body, root,
bed, matrix, and eponychium of the nail. ±irst, define each of
these parts. Ten, tell if this nail is likely to grow back.
24.
On an outline diagram of the human body, mark off various
regions according to the rule of nines. What percentage of the total
body surface is affected if the skin over the following body parts is
burned? (a) the entire posterior trunk and buttocks, (b) an entire
lower limb, (c) the entire front of the leF upper limb.
25.
A common belief is that having your hair cut makes it become
thicker. Explain why this belief is not true.
Critical Thinking
and Clinical Application
Questions
1.
Dean, a 40-year-old aging beach boy, is complaining to you that
although his suntan made him popular when he was young,
now his face is all wrinkled, and he has several darkly pigmented
moles that are growing rapidly and are as big as large coins. He
shows you the moles, and immediately you think “ABCD.” What
does that mean and why should he be concerned?
Related Clinical Terms
Albinism
(al
9
bĭ-nizm;
alb
5
white) Inherited condition in which
melanocytes do not synthesize melanin owing to a lack of
tyrosinase. An albino’s skin is pink, the hair pale or white, and
the irises of the eyes unpigmented or poorly so.
Boils and carbuncles
(kar
9
bung-klz; “little glowing embers”)
Inflammation of hair follicles and sebaceous glands in which an
infection has spread to the underlying hypodermis; common
on the dorsal neck. Carbuncles are composite boils. A common
cause is bacterial infection.
Cold sores (fever blisters)
Small fluid-filled blisters that itch and
smart; usually occur around the lips and in the mucosa of the
mouth; caused by a herpes simplex infection. Te virus localizes
in a cutaneous nerve, where it remains dormant until activated
by emotional upset, fever, or UV radiation.
Contact dermatitis
Itching, redness, and swelling, progressing to
blister formation; caused by exposure of the skin to chemicals
(e.g., poison ivy oleoresin) that provoke an allergic response in
sensitive individuals.
Decubitus ulcer
(de-ku
9
bĭ-tus) Localized breakdown and ulceration
of skin due to interference with its blood supply. Usually occurs
over a bony prominence, such as the hip or heel, that is subjected
to continuous pressure; also called a bedsore.
Dermatology
Te branch of medicine that studies and treats
disorders of the skin.
Eczema
(ek
9
ze-mah) A skin rash characterized by itching, blistering,
oozing, and scaling of the skin. A common allergic reaction in
children, but also occurs (typically in a more severe form) in
adults. ±requent causes include allergic reactions to certain foods
(fish, eggs, and others) or to inhaled dust or pollen. ²reated by
methods used for other allergic disorders.
Epidermolysis bullosa (EB)
A group of hereditary disorders
characterized by inadequate or faulty synthesis of keratin,
collagen, and/or basement membrane “cement” that results
in lack of cohesion between layers of the skin and mucosa.
A simple touch causes layers to separate and blister. ±or this
reason, EB victims are called “touch-me-nots.” In severe cases
fatal blistering occurs in major vital organs. Because the blisters
rupture easily, victims suffer frequent infections. ²reatments are
aimed at relieving the symptoms and preventing infection.
Impetigo
(im
0
pĕ-ti
9
go;
impet
5
an attack) Pink, fluid-filled, raised
lesions (common around the mouth and nose) that develop a
yellow crust and eventually rupture. Caused by staphylococcus
infection, it is contagious, and common in school-age children.
Porphyria
(por-fer
9
e-ah; “purple”) An inherited condition in which
certain enzymes needed to form the heme of hemoglobin
of blood are lacking. Without these enzymes, metabolic
intermediates of the heme pathway called porphyrins build up,
spill into the circulation, and eventually cause lesions throughout
the body, especially when exposed to sunlight. Te skin becomes
lesioned and scarred; fingers, toes, and nose are disfigured; gums
degenerate and teeth become prominent. Believed to be the basis
of folklore about vampires.
Psoriasis
(so-ri
9
ah-sis) A chronic autoimmune condition
characterized by raised, reddened epidermal patches covered
with silvery scales that itch or burn, crack, and sometimes bleed
or become infected. When severe, it may be disfiguring and
AT T H E C L I N I C
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