Lecture 2: ANATOMY OF SKIN - Part 2 Flashcards
Where is hair found?
All over the body (only prominent on the head) except palms of hands and soles of feet
What does hair consist of?
Hair shaft, hair follicle, arrector pili muscle and sebaceous gland
What happens when the arrector pili muscle contracts?
Causes the hair to raise
What does a sebaceous gland do?
Produce sebum which acts as a natural moisturiser/water repellent
Where is sebum produced more?
On the head, shoulders and face
What is lanolin?
Sheep sebum which is used in skincare
What is acne?
Blockage of hair follicles and infection
What does increased sebum do?
Increase the risk of acne
What are the two types of sweat glands?
Eccrine and apocrine
Where are eccrine glands?
Everywhere
What is the role of eccrine glands?
Thermoregulation
What is the role of apocrine glands?
Specialised
Where are apocrine sweat glands?
Situated deeper in the skin, release into base of the hair follicle
How are apocrine secretions described?
Oily
What are the 3 types of receptors?
Tactile, lamellar and bulbous
What receptor is deeper?
Lamellar are deeper than tactile receptors
What do nails do?
Protect fingertips and enhance sensation
What do sensory receptors require?
Deformation
What does high pigmentation do?
Protects from UV radiation
What does low pigmentation do?
Helps with vitamin D production
What does melanin pigment do?
Absorbs UV light to protect from UV damage (damage DNA)
Where is melanin produced?
In cells called melanocytes
How is melanin transported?
By melanosomes (vesicles) to the epidermal cells
Where are melanocytes found?
Only in the stratum basale
Do melanocytes shed?
No
Where are melanosomes found?
Throughout the epidermis
Do melanosomes shed?
Yes. With the keratinocytes
Where does the density of melanocytes vary?
Throughout the body but not between races
What is a mole?
Cluster of melanocytes
What causes a mole?
Overproliferation can be cause by sun exposure
What is a freckle?
Melanocytes overproducing melanosomes
What causes a freckle?
Overproduction triggered by sun exposure
What does more UV mean?
More pigment
What does less UV mean?
Less pigment
What is vitamin D deficiency?
Rickets
What is vitamin D essential for?
Normal calcium metabolism and strong bones
What does vitamin D deficiency also effect?
Mood
What is UV exposure in skin required for?
Vitamin D synthesis
Where is there a greater incidence of lightly pigmented skin?
At higher latitudes
What people are more susceptible to Vitamin D deficiency?
Highly pigmented people, particularly at extreme latitudes
What does New Zealand have one of the highest rates for worldwide?
Skin cancer
What proportion of NZers are pakeha (European descent, mostly British)?
Large proportion (74%)
What is the UV of NZ?
Intense (elliptical orbit of the sun, latitude, thin ozone)
What country also has high skin cancer rates?
Australia
What are the types of skin cancer?
Basal cell carcinoma and malignant melanoma
How is basal cell carcinoma described?
Common but relatively benign
Where does basal cell carcinoma originate?
In the stratum basale
Metastasis is ______ for basal cell carcinoma?
Rare
What is metastatis?
Breaking off and moving to and growing in another part of the body
How is Malignant melanoma described?
Rare but deadly if not treated
Where does malignant melanoma originate?
In the melanocytes (pigmented)
Malignant melanoma is ______ metastatic
Highly
What does the mortality rate of malignant melanoma depend on?
The tutor (thickness and depth as it is more likely to get into the circulatory system and cause damage to organs)
What is tattoo?
Artificial pigmentation (usually ink) deposited deep within the skin
Where is the ink of a tattoo deposited?
Into the dermal layer so it is effective and doesn’t shed
What is done with the tattoo ink?
It is captured inside the immune cells/scar tissue but not broken down
What happens to lymph nodes in tattoo?
They may become pigmented as the tattoo breaks down
What are the types of tattoo?
Trauma, decorative and cosmetic (e.g. eyebrows)
What is the Polynesian connections of tattoos?
Maori, ta moko
Samoan, Pe’a
