Lecture 2 Flashcards
What are the 4 key accessory structures of the skin?
Hair, Sweat glands, Nails, Receptors
What is hair made of?
Dead, keratinised cells that have been made in a hair follicle. This hair projects from a hair follicle
What is the function of the arrestor pili muscle?
Attaches to hair follicle and contracts to produce goosebumps (improves insulation) - hair shaft stands up straight.
Describe the Root Hair Plexus
It is a collection of sensory nerves at the base of each hair follicle which causes heightened sensation
What are sebaceous glands?
Glands in the skin that produce oily secretion called sebum
What are the functions of sebum?
Nourishes hair shaft and naturally moisturises the skin, Water repellent
How does sebum relate to acne?
Sebum blocks the hair follicles. Combined with infection due to increased sebum production results in acne
What is the name for sebum secreted by sheep and what is it’s function?
Lanolin and it is purified and used commercially in skin products
What is the main difference in the location of eccrine and apocrine glands?
Eccrine glands are found in most areas of the skin whereas apocrine glands are found in specific areas such as the armpit, groin and around the nipples
What do eccrine sweat glands secrete?
Pour watery secretions directly onto the skin surface
What is the function of eccrine sweat glands?
Thermoregulation, salt excretion, antibacterial action.
What do apocrine sweat glands secrete and where?
Sticky/oily, sometimes odorous secretions into the base of hair follicles. This is influenced by hormones e.g. lactation
What are the 3 types of sensory receptors in the skin?
Tactile, lamellar, bulbous
What is the function of nails in terms of the skin?
Protect finger/toe tips, Enhance sensation (by membrane deformation)
What are the characteristics of ageing skin?
Thin epidermis and dermis, sagging/wrinkling due to diminished collagen, slower skin repair, drier epidermis due to decreased sebum, impaired cooling due to less sweat, pale skin, grey hair
How does tobacco cause premature skin ageing?
Damages collagen and elastin, reduces healing, causes acne and cancers .
How does vaping affect the skin?
Contains nicotine, which reduces blood circulation to the dermis causing contact dermatitis (rash)
Describe the function of melanin
Absorbs UV light to protect cells from sun damage, produced in Melanocytes (stratum basale) and transported to epidermal cells in melanosomes
Where are melanocytes found and what is a characteristic of their prolificity?
Only in the stratum basale so they are NOT shed. The density of melanocytes varies throughout the body and through time
What is a mole and what is it the cause of one?
A cluster of melanocytes. Over-proliferation can be caused by sun damage
What is a freckle and what causes them?
Melanocytes overproducing melanosomes. Over-production is triggered by sun exposure
What is the function of Vitamin D?
Calcium metabolism and bone strength. Also affects mood
What disease does a severe Vitamin D deficiency cause?
Rickets
How is the skin involved in vitamin D synthesis?
UV exposure to the skin is required for synthesis.
What is a basal cell carcinoma and where does it originate?
A common, relatively benign form of skin cancer that originates in the stratum basale of the epidermis and has rare metastasis (spread)
What is a malignant melanoma and where does it originate?
Rare form of skin cancer that is highly metastatic and can be deadly in left untreated that originates in melanocytes
Why do tattoos remain in the skin permanently?
They are deposited into the dermis layer of the skin, which is not shed. Cannot be completely broken down by immune cells.
