INTEGUMENTARY SYSTEM The skin (including sweat and oil glands), hair and nails.
Skin Appendages: Hair, Nails, Glands
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Transcript of Skin Appendages: Hair, Nails, Glands
SKIN APPENDAGES: HAIR, NAILS, GLANDSSeptember 23-24 2014
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
You’ll be able to
identify
sebaceous glands on slides by
looking for la
rge, roundish glands
with a LARGE duct that e
mpties
into the hair f
ollicle.
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
Fun fact: the ‘pores’ on our faces are actually hair follicles
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) 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
Notice that sweat glands, since they empty into the skin, are often farther and deeper than sebaceous glands
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• The hair follicle is surrounded by a thin layer of epidermal
tissue.
• The follicle
is slanted
unless the
arrector pili
muscles
are
contracted Dermal
epidermal
hair bulb
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
Change the words on the diagram of your guided notes
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 hairOval shaft = silky, wavy hairFlat 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
2
3
4
5
6
7
8