SKIN APPENDAGES &
SKIN CANCER
September 28-29 2015
Skin Appendages
The skin appendages include cutaneous glands, hair, and
nails.
Cutaneous Glands
What is cutaneous?
What is an exocrine gland?
Cutaneous Glands
What is cutaneous? Relating to the skin
What is an exocrine gland?
A gland that releases
its product to a
particular site, rather
than into the blood
stream. (Endocrine
glands release their
products to the blood).
Cutaneous Glands
1) Sebaceous (oil) glands
• Found everywhere except palms of hands and soles of
feet
• The ducts mostly empty into hair
follicles
• Produce oily product called sebum
• Functions:
• Keep hair and skin from drying out
• Kill bacteria
• Become much more active in
adolescence
Cutaneous Glands
1) Sebaceous (oil) glands
Fun fact: the ‘pores’
on our faces are
actually hair follicles
• Found everywhere except palms of hands and soles of
feet
• The ducts mostly empty into hair
follicles
• Produce oily product called sebum
• Functions:
• Keep hair and skin from drying out
• Kill bacteria
• Become much more active in
adolescence
Acne occurs when the hair follicle is clogged
with sebum.
Cutaneous Glands
2) Sweat (sudoriferous) glands
• Eccrine glands produce sweat (water, salt, urea, lactic acid)
• Duct lead to pores in skin
• Functions
• Thermoregulation
• Excretion
• Bacterial inhibition (sweat is acidic)
• Apocrine glands produce a milky secretion
fully of fatty acids and proteins.
• Small duct leads to hair follicle
• Function: Pheromone!
Cutaneous Glands
2) Sweat (sudoriferous)
Notice that sweat glands, since
they empty into the skin, are
glands often farther and deeper than
sebaceous glands
• Eccrine glands produce sweat (water, salt, urea, lactic acid)
• Duct lead to pores in skin
• Functions
• Thermoregulation
• Excretion
• Bacterial inhibition (sweat is acidic)
• Apocrine glands produce a milky
secretion full of fatty acids and
proteins.
• Duct leads to hair follicle
• Function: Pheromone!
Fun fact: Randy Thornhill’s work
Cutaneous Glands – Quick Review
Make a Venn Diagram comparing the three types of
cutaneous glands. You may work with a partner.
5 min
Hair follicle
Why/when do the arrector pili muscles contract?
The arrector pili muscles contract when we are
cold, to raise the hairs and reduce heat loss
• The hair follicle is surrounded by a thin layer of epidermal
tissue.
• The follicle
is slanted
unless the
arrector pili
muscles
are
contracted
Change the words on the diagram of
your guided notes
Dermal
epidermal
hair bulb
Hair
• Hair can be divided into the shaft (part outside of body)
and root (inside body)
• Hair is produced by epithelial cells in the hair bulb, but as
the cells are pushed away from the bulb they begin to die.
• Like the outer layer of the skin, the
hair shaft is composed of dead,
keratinized cells.
Fun fact:
Round shaft = straight, coarse hair
Oval shaft = silky, wavy hair
Flat shaft = curly hair
Nails
• Produced by epithelial cells
• The nail root, closest to the nail matrix, is living
• The outer part, like the hair and skin, consists of dead
keratinized cells.
Fun fact:
Fingernails
are a derived
trait in
primates
Quick Review
Turn & Talk. Be prepared to share with the class.
Are the skin appendages (cutaneous glands, hair, hair
follicles, and nails) found in the dermis or epidermis?
Justify your answer.
Quick Review
Turn & Talk. Be prepared to share with the class.
Are the skin appendages (cutaneous glands, hair, hair
follicles, and nails) found in the dermis or epidermis?
Justify your answer.
They are in the epidermis, because the epidermis
surrounds and gives rise to these structures. However,
these structures usually sit deeper than the most of the
epidermal tissue.
Label the diagram
Label the diagram
• A: epidermis
• B: dermis
• C: hypodermis
• 1: hair shaft
• 2: pores
• 3: Eccrine gland
• 4: sebaceous gland
• 5: capillary
What did we talk about today that
you don’t see on this diagram?
Label the diagram
• A: epidermis
• B: dermis
• C: hypodermis
• 1: hair shaft
• 2: pores
• 3: Eccrine gland
• 4: sebaceous gland
• 5: capillary
What did we talk about today that
you don’t see on this diagram?
Apocrine glands.
Identify the parts of the skin
1
4
5
6
2
7
8
3
Common Types of Skin Cancer
There a three main types of skin cancers, defined by the type
of cell from which they arise.
Basal cell carcinoma – arise
from the basal edge of the
epithelial tissue.
Squamous cell carcinoma –
arise from the keratinproducing cells in the middle
of the epithelial tissue.
Melanoma – arise from the
melanin-producing cells at
the basal edge of the
epithelial tissue
Basal Cell Carcinoma
• Most common form of
skin cancer
• Affects ~2.8 million
people in the US each
year
• Slow-growing and
rarely fatal
Squamous Cell Carcinoma
• Second most
common form of
skin cancer
• Affects ~700,000
people in the US
each year
• Grow and invade
surrounding tissue
quickly
• <5% are fatal
Melanoma
• Third most common skin
cancer
Melanoma may be the least common
• Affects ~76,000 people in the
type of skin cancer, but it is by far the
US each year
most deadly.
• Quickly metastasizes
while rates of most other
(spreads) toMoreover,
blood vessels
cancers– are
declining in the US (due
and lymph nodes
which
a reduction
allows it to to
spread
to otherof smoking) melanoma
are increasing.
locations inrates
the body
• Fatal in more than 10% of
cases
Closure
• What were our objectives today?
How did we meet them?
• What was our learner profile trait and how did we use it?
• How does what we did today address our unit objective?