1. Skin Appendages & Skin Cancer
September

2. Skin Appendages
The skin appendages include cutaneous glands, hair, and nails.

3. Cutaneous Glands
What is cutaneous? What is an exocrine gland?

4. 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).

5. Cutaneous Glands 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 large, roundish glands with a LARGE duct that empties into the hair follicle.

6. Cutaneous Glands Sebaceous (oil) glands
Fun fact: the ‘pores’ on our faces are actually hair follicles
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

7. Acne occurs when the hair follicle is clogged with sebum.

8. Cutaneous Glands 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!
Apocrine glands active after puberty and during stress/pain/ sexual activity

9. Cutaneous Glands Sweat (sudoriferous) glands
Notice that sweat glands, since they empty into the skin, are often farther and deeper than sebaceous glands
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
Apocrine glands active after puberty and during stress/pain/ sexual activity

10. Cutaneous Glands – Quick Review
Make a Venn Diagram comparing the three types of cutaneous glands. You may work with a partner. 5 min

11. Change the words on the diagram of your guided notes
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

12. 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

13. 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

14. 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.

15. 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.

16. Label the diagram

17. Label the diagram A: epidermis B: dermis C: hypodermis 1: hair shaft
2: pores
3: Eccrine gland
4: sebaceous gland
5: nerve
Also visible on this diagram are root hair plexus (nerve endings) and arrector pili muscle. You can’t see apocrine glands
What did we talk about today that you don’t see on this diagram?

18. Label the diagram A: epidermis B: dermis C: hypodermis 1: hair shaft
2: pores
3: Eccrine gland
4: sebaceous gland
5: capillary
Also visible on this diagram are root hair plexus (nerve endings) and arrector pili muscle. You can’t see apocrine glands
What did we talk about today that you don’t see on this diagram?
Apocrine glands.

19. Identify the parts of the skin1 4 5 6 2 7 8 3

20. 1) Hair shaft, 2) pore, 3) sweat glad, 4) sebaceous gland, 5) blood vessel

21. 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 keratin-producing cells in the middle of the epithelial tissue.
Melanoma – arise from the melanin-producing cells at the basal edge of the epithelial tissue
Excess sun exposure increases the risk of each of these cancers

22. Basal Cell Carcinoma Most common form of skin cancer
Affects ~2.8 million people in the US each year
Slow-growing and rarely fatal

23. 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

24. Melanoma Third most common skin cancer
Affects ~76,000 people in the US each year
Quickly metastasizes (spreads) to blood vessels and lymph nodes – which allows it to spread to other locations in the body
Fatal in more than 10% of cases
Melanoma may be the least common type of skin cancer, but it is by far the most deadly.
Moreover, while rates of most other cancers are declining in the US (due to a reduction of smoking) melanoma rates are increasing.

25. 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?
How does what we did today address our TOK connection?