The Skin Flashcards
What are the appendages of the skin?
hair
nails
sudoiferous glands
sebacious glands
Characteristics of healthy skin:
smooth
soft
slightly moist
slightly acidic (pH 5.5)
List the functions of the skin
Protection Heat regulation Absorption Sensation Secretion Excretion
Describe the main protective functions of the skin
1) Barrier function: the cornecytes and the intercellular matrix in between (composed of lipids) act as a protective barrier keeping pathogens from entering skin. Protects against TEWL
2) Acid mantle: a protective film on surface of skin. consists of sebum, lipids, sweat and water and is slightly acidic (lubricates and kills bacteria)
3) Regenerative ability and hyperproduction of cells (platelets and clotting)
5) Protect against UV rays - melanocytes produce melanin
What is transepidermal water loss? (TEWL)
Evaporation of water on the skin’s surface, occurs when the barrier function is compromised
What is the main function of the sudoiferous gland?
Thermoregulation. Heat is released through perspiration.
What are 2 automatic responses to warm body?
Goosebumps (arrector pilli muscles)
Shivering
How does our skin regulate our temperature?
Perspiration
Evaporation
radiation
insulation
What does it mean that skin in selectively permeable?
allows absorption of beneficial ingredients (oxygen, water, vitamin D from sun)
How are topical products absorbed into skin?
follicle walls sebacious glands sudoiferous glands intercellular (between cells) intracellular (through cells)
*dependent on molecule size
How does our skin help us experience our senses?
Sensory receptors in our skin help us feel touch, pressure, pain, heat, cold sensations
Where are sensory receptors located?
The Dermis
What are the effects of estrogen on the skin?
Anti-innflammatory
Antioxidant
Helps mainatin moisture
helps with tissue repair
Describe the secretion function of the skin
Sebacious glands: secrete sebum
sebum coats the skin and slows TEWL, keeps skin soft and protects against bacteria/elements
What is the secondary function of the sudoiferous glands?
They excrete small amounts of salts, chemicals and water through pores to help detoxify the body
What is an appocrine gland?
- Sweat glands located underarms and genital area
- attatched to hair follicles
- sensitive to adrenalin active during sex/stress
- odor associated
What is an eccrine gland?
- sweat glands not attched to follicle, release sweat through pores all over body
- associated with excersize and heat
What is normal temperature of body?
37 degress
where are melanocytes found?
Basal layer of epidermis and papillary layer of dermis
How is the epidermis nourished?
blood and lymph from the dermis
Why do people have different skin colors?
Skin color is not dependent on the number of melanocytes everyone has the same amount.
Darker skinned people have larger melanosomes and therefore more melanin
Describe the deepest layer of the skin
The hypodermis:
- connective tissue, mainly adipose tissue
- gives insulation, stores energy, necessary for hormone production
Where are thick networks of collagen and elastin found?
the reticular layer of th dermis
Define collagen
gives skin its strength
Define Elastin
gives skin its elasticity
What is hyaluronic acid? and what does it do?
Hyaluronic acid is a water binder molecule (GAG) found in the intercelluar space of the dermis.
Attacts water and helps keep skin hydrated
What is the dermal epidermal junction?
Where the dermis meets the epidermis and provides nourishment through blood and lymph vessels
define fibroblasts
cells found in the dermis that stimulate the production of collagen and elastin
what do keratinocytes produce? what layer is it produced?
keratin
produced in the statum granulosum
pheomelanin
red/yellow colored melanin
what is dark brown/ black melanin called?
eumelanin
define tyrosinase
An enzyme that stimulates melanoytes to produce melanin
List structures found in the dermis
Collagen Elastin Hair follicles sebacious glands sudoiferous glands arrector pilli muscles Nerve endings capillaries
What occurs in the basal layer?
- Mitosis (proliferation of keratinocytes)
- Melanocytes produce melanin pigment
- Stem cells differentiate into other cells
What happens in the stratum spinosum?
- junctions between keratinocytes are formed called DESMOSOMES which hold cells together
- langerhans cells (guard cells) found in this layer
What happens in the Stratum granulosum?
- desmosomes are dissolved
- Keratin is produced by keratinocytes
- lintercellular ipids are produced here
what do Lamellar granules do?
help produce lipids for the intercellular matrix
Where on the body is the Stratum Lucidum layer found?
only found palms of hands and soles of feet
clear layer
Describe the outtermost layer of the epidermis
Stratum Corneum:
- composed of corneocytes (dead cells) and intercelluar matrix which forms a skin barrier
- desquamation the shedding of dead skin cells occurs constantly and cells from lower layer replace these cells
How long is cell turnover in average person?
28 days (slows down as we age)
Define glycation
- glycation is when glucose molecules bind to proteins and negatively affect their biological functioning.
- glucose attches to collagen causing wrinkles and elastin causing stiffness
differentiate between UV Rays
UVC - stopped by ozone layer
UVB- shorter wavelengths, cause burning, cancer and give us vit D
UVA- aging rays penetrate into dermis and damage collagen and elastin
List signs of photoaging
hyperpigmentation telangiectasia wrinkles sagging cancers
What are free radicals?
What causes them?
unstable electrons in our bodies that steal electrons from other molecules causing a chain reaction of destruction in our body
Define antioxidants
molecules that have extra electons and are vital to stabilize free radicals on our bodies
List 4 antioxidants
vitamin C
Vitamin E
Niacinamide
green Tea
What causes skin cancer?
UV rays cause damage to the DNA
cells divide rapidly and unevenly
What are langerhans cells and where are they found?
They are cells that provide immunity (guard cells) and are found in the Stratum spinosum.
