Introduction to Dermatology & the Epidermis Flashcards
Are skin diseases common?
Yes
Fill in the following for: Skin Type I
- Hair
- Eyes
- Skin
- Freckles
- Sunburn
- Tan
Hair- Red/Blond Eyes- Blue/Green Skin- White Freckles- +++ Sunburn- Always Tan- 0
Fill in the following for: Skin Type II
- Hair
- Eyes
- Skin
- Freckles
- Sunburn
- Tan
Hair- Blond/Brown Eyes- Light to medium Skin- Fair Freckles- ++ Sunburn- Easily Tan- Minimally
Fill in the following for: Skin Type III
- Hair
- Eyes
- Skin
- Freckles
- Sunburn
- Tan
Hair- Brown Eyes-Medium to Dark Skin- Light brown Freckles- + Sunburn- Initially Tan-Gradual
Fill in the following for: Skin Type IV
- Hair
- Eyes
- Skin
- Freckles
- Sunburn
- Tan
Hair- Medium to Dark Eyes- Dark Skin- Moderate Brown Freckles- 0 Sunburn- Minimally Tan- Tans Well
Fill in the following for: Skin Type V
- Hair
- Eyes
- Skin
- Freckles
- Sunburn
- Tan
Hair- Dark Eyes- Dark Skin- Dark Brown Freckles- 0 Sunburn- Rarely Tan- Dark Tan
Fill in the following for: Skin Type VI
- Hair
- Eyes
- Skin
- Freckles
- Sunburn
- Tan
Hair- Dark Eyes- Dark Skin-Black Freckles- 0 Sunburn- Never Tan- Always Tan
Is skin color due to the number of melanocytes in the skin?
No.
What are the two types of melanin produced?
Eumelanin & Pheomelanin
What type of pigment does eumelanin produce?
Black and brown pigment
What type of pigment does pheomelanin produce?
Yellow to red-brown pigment
What is the distribution of melanosomes in light skin?
Melanosomes are distributed in clusters above the nucleus
What is the distribution of melanosomes in dark skin?
Melanosomes are distributed individually throughout the cytoplasm
Name some of the functions of skin.
- Decoration/ beauty
- Barrier
- Vitamin D synthesis
- Water Homeostasis
- Thermoregulation
- Insulation/ Calorie Reservoir
- Touch/ Sensation
What are the components of the epidermis?
A stratified squamous epithelial layer
What are the components of the dermis?
Papillary layer & Reticular layer
What is the Papillary layer composed of?
Loose connective tissue that lies just immediately under the epidermis
What is the reticular layer?
Deeper part of the dermis composed of dense connective tissue
Name 5 adnexal structures.
- Apocrine glands
- Eccrine glands
- Hair
- Nails
- Sebaceous glands
Subcutaneous fat is composed of what type of cells?
Adipocytes
Where is thick skin found?
Palms and soles
What converts 7-dehyrocholesterol to Vitamin D3 (cholecalciferol)?
UV light in the skin
What converts cholecalciferol (Vitamin D3) to Calcidiol (25-hydroxy Vitamin D)?
Liver
What converts calcidiol (25- hydroxy Vitamin D) to the ACTIVE 1-25- dihydroxy-Vitamin D (calcitriol)?
Kidney
What do keratinocytes produce?
Keratin, the major intracellular fibrous protein of the skin
What is the precursor cell of melanocytes?
Neural crest
What do melanocytes produce?
melanin, a pigment derived from tyrosine
Autoimmunity to melanocytes causes what condition?
Vitiligo
What is the role of Langerhans cells?
Small numbers in all of the epidermal layers that act as dendritic cells in the skin
Where are Langerhans cells derived from?
Bone marrow stem cells
Basal keratinocytes are considered what type of cell?
Stem cells
Hemidesmosomes attach what two structures?
They attach basal cells firmly to the basal lamina of the dermal epidermal junction
Antibodies to proteins in teh hemidesmosomes may cause autoimmune blistering. What is this called?
Bullous pemphigoid
What causes Dystrophic Epidermolysis Bullosa?
Genetic defects in Collage VIII
What causes Junctional EB?
Genetic defects in Laminin-5
What is the function of desmosomes?
Attach keratinocytes to each other
Antibodies to proteins in the desmosomes may cause what autoimmune disease?
Pemphigus vulgaris causes blistering
What causes Epidermolysis bullosa simplex?
Congenital defects in Keratin filaments 5 and 14
What are tonofilaments?
Protein structures (keratin filaments) that insert into the dense plaques of desmosomes on the cytoplasmic side of the plasma membrane
What is the appearance of stratum spinosum?
prickly
What proteins are synthesized in the stratum spinosum?
Involucrin
Membrane coating granules
What type of granule is found in stratum granulosum?
Keratohyalin granules
What is the function of filaggrin?
Cross-links keratin tonofilaments and is important in the barrier function of the skin
Filaggrin is mutated in what two dry skin conditions?
- Ichthyosis
2. Atopic dermatitis
What is unique about keratinocytes in the stratum lucidum layer?
They no longer have nuclei or organelles.
This layer is thin
Are desmosomes still connected in the stratum corneum?
Yes
Meissner’s corpuscles are found in what part of the dermis?
What is their function?
Papillary layer
Sense touch
Blood vessels in the reticular layer have what function?
Thermoregulation
What and where are Pacinian corpuscles found?
Found: Reticular layer
Function: Sense vibration, pressure and touch
What type of skin contains Meissner’s corpuscles?
Dermal papillae of thick skin
What do Meissner’s corpuscles consist of?
Schwann cells and sensory nerve terminals wrapped by fibroblasts and collagen
What skin type contains Pacinian corpuscles?
Thick and thin skin
What is the appearance of Pacinian corpuscles?
Concentric layers are composed of flattened connective tissue-like cells
Where are apocrine sweat glands located?
Axillary, pubic, and perianal regions
Where are eccrine sweat glands not found?
Not found in the lips, under the nails or on the glans penis, glans clitoris or labia minora
Describe the consistency of aporcine products vs. eccrine.
Apocrine- Milky, viscid, carbohydrate-rich secretions
Eccrine- Watery, enzyme-rich secretion, initially isotonic
What is the function of eccrine glands?
Thermoregulation
Describe the structure of hair.
Central medulla of soft keratin, and a cortex and cubicle of hard keratin
Where does the pigment of hair come from?
Melanocytes
What causes “goose bumps”?
Contraction of arrector pili muscle
What do sebaceous glands secrete?
Sebum, a complex mixture of lipids
Where do sebaceous glands secrete sebum?
Upper one-third of hair follicles. Accelerated during puberty
