Lecture Two - Skin Flashcards
1
Q
Skin accessory structures
A
- hair
- sweat glands
- receptors
- nails
2
Q
Where is hair found
A
All over the body except palms, soles and lips
3
Q
What is hair made of?
A
Made of dead, keratinised cells produced inside a hair follicle
- hair shafts projects from the follicle
4
Q
Accessory structures - hair
A
- arrector pili muscle
- root hair plexus
- sebaceous glands
5
Q
What does the arrector pili muscle do?
A
- contraction produces ‘goose bumps’
- improves insulation
6
Q
What is the root hair plexus and what does it do?
A
- a collection of sensory nerves at the base of each hair follicle
- heightened sensation
7
Q
What do the sebaceous glands do?
A
- produce oily secretion called sebum
- nourished hair shaft and naturally moisturises skin
- water repellent
- blocked hair follicles + infecutoion due to increase sebum production leads to acne
8
Q
What does increased sebum production do
A
- results in blocked hair follicles and infection leading to acne
9
Q
What is lanolin?
A
- sheep sebum
- purified and used commercially in skin care products
10
Q
A
11
Q
Where are eccrine sweat glands found?
A
- found in most areas of the skin
12
Q
What do eccrine sweat glands do?
A
- pour watery secretions directly onto the skin surface
- important in thermoregulation and excretion
- some antibacterial action
13
Q
Where are apocrine sweat glands found?
A
- found in specific areas
E.g: armpit, groun and around nipples
14
Q
What do apocrine sweat glands do?
A
- secrete sticky/oily and at times potentially odorous secretions into the base of the hair follicle
- influences by hormones e.g lactation
15
Q
A
16
Q
Receptors
A
- tactile
- lamellar
- bulbous
17
Q
What do nails do?
A
- protect fingertips / toes
- enhance sensation
- sensory receptors require deformation
18
Q
A
19
Q
How does skin anatomy relate to its function ?
A
- aging
- pigmentation
- protection from UV radiation (high pigmentation)
- vitamin D production (low pigmentation)
- skin cancer / vitamin D insufficiency
- tattoo (artificial pigmentation)
20
Q
Skin aging
A
- thin epidermis
- thin dermis (sagging/wrinkling) - reduced collagen
- slower skin repair
- drier epidermis (less sebum)
- impaired cooling (less sweat)
- less pigmentation (pale skin, grey hair)
21
Q
Smoking and skin aging - tobacco
A
- contains agents that accelerate aging
- damages collagen and elastin in the skin
- linked with poor wound healing, acne, skin and oral cancers
22
Q
Vaping and skin aging
A
- contains nicotine
- nicotine reduces blood circulation in the dermis
- contact? Dermatitis (skin inflammation) due to metal coating on e-cigarettes
23
Q
Difference betweeen a mole and a freckle
A
Mole:
- cluster of melanocytes
- over proliferation can be caused by sun exposure
Freckle:
- melanocytes overproducing melanosomes
- over produciotn triggered by sun exposure
24
Q
Skin _____ matches ____ exposure
A
Skin pigmentation matches UV exposure ( in indigenous populations)
25
Vitamin D is essential for…
- normal calcium metabolism
- strong bones
26
Vitamin D diffieicny causes …
- rickets
- affects mood
27
What is required for vitamin D synthesis
- UV exposure in skin
This explains the greater incidence of lightly pigmented skin at higher latitudes
28
Who is more susceptible to vitamin D dificiency ?
Highly pigmented people are more susceptible to vitamin D deficiency, particularly at extreme latitudes
29
Why NZ has one of the highest rates of skin cancer world wide… why?
- large European population
- intense UV (elliptical orbit of sun, latitude, thin Ozone)
- Australia is similar
30
What absorbs UV light? And what does it result in?
Melanin pigment absorbs UV light, protecting cells from UV damage
31
Where is melanin produced?
In melanocytes (cells)
32
How is melanin pigment transferred to epidermal cells?
Melanin pigment is transferred to epidermal cells by melanosomes (vesicles containing melanin)
33
34
35
Where are melanocytes found
Melanocytes are only found in the stratum basale - they are not shed
36
Where are melanosomes found
Melanosomes are found throughout the epidermis - is shed with keratinocytes
37
Desity of melanocytes ?
Varies throughout the body and through time
38
39
Basal cell carcinoma
- common but relatively benign
- originates in stratum basale (gets moved away from blood stream via epidermis shedding)
- metastasis (spread) is rare
40
Malignant melanoma
- rare but deadly if not treated
- originates in the melanocytes (pigmented)
- highly metastatic
- mortality rate dependent upon tumour
41
The thickness of melanoma highly correlates with mortality rate
42
Tattoo and how it relates to skin anatomy
Artificial pigmentation (usually ink) deposited deep within the skin
- dermal layer, i.e - not shed
- captured (but not broken down) inside immune cells/scar tissue
- ‘Lena’ tattoo, pigmentation of lymph nodes
43
Pigment in lymph nodes =
Tattoo
Not melanoma
44
Types of tattoo
- trauma
- decorative
- cosmetic tattoos
45
Tattoo Polynesian connection
- Māori, ta moko
- Samoan, Pe’a
46
Skin is composed of…
All four basic tissue types:
Epithelial, muscular, nervous and connective
