Lecture 10 Flashcards
Blister
Seperation of dermis from epidermis
Acute severe friction
Callus
Thickening of epidermis
Chronic friction
Epidermis
Superficial epithelial tissue
Dermis
Deeper fibrous connective tissue
Vascularized
Hypodermis
Fatty layer under dermis
Superficial fascia, subcutaneous layer
Adipose and areolar connective tissue
Thickens during weight gain
Epidermis
Different layers of cells at different life stages
5 strata
Stratum basal
Cuboid cells right above dermis
Cells are constantly dividing
Contains melanocytes
Stratum spinosum
Cells look like that have sharp spiny edges
Attached to one another with desmosomes
Pre-keratin
Stratum granulosum
Cells have keratohyalin granules
Thick cell membrane
Stratum lucidum
Only in areas with thick skin
Cells are dead, with no organelles or nucleus
Filled with keratin
Stratum corneum
Top most layer
Cells are dead
No organelles/nucleus
Filled with keratin
Keratinocytes
Cells of the skin
Produce keratin
Melanocytes
Produce melanin
Increase production in response to UV light
Merkel’s cells
Touch receptors of the skill
Connected to nerves
Dendritic cells
Immune cells in skin
Dermal papillae
Epidermal/dermal ridges
Increase friction and grip
Sweat pores open along the crests of the ridges
Three pigments
- Melanin
- Carotene
- Hemoglobin
Melanin
Yellow to reddish to brown to black
Different types
Without it, epidermis would be translucent
Provides protection from UV rays
Carotene
Yellow-orange pigment
Accumulates in stratum corneum and hypodermis
Melanin granules
On superficial side of keratinocytes
Light skin
Melanin is digested by lysosomes short distance from basal layer
Not digested in dark skin
Dangers of UV rays
Sunlight decreases production of folic acid (anticancer)
Production of melanin to prevent loss of folic acid
Essentialness of UV rays
Needed during pregnancy to prevent neural tube defects
Sunlight stimulates deep epidermis production of VitD
Freckles
Increased melanin in stratum basale
Due to repeated exposure to light
Moles
Clusters of melanocytes converted into a melanin containing cell
Transdermal patch
Drug molecules diffuse through epidermis into dermis
Works well with small, lipid soluble molecules
Appendages of skin
Nails, hair/follicles, sebaceous glands, sweat glands
Nails
Modified epidermis, dead keratinized cells Hard keratin (unlike skin)
Nail bed
Deep layers of epidermis
Pink part of nail
Due to rich underlying capillaries
Lunule
Thick bed called nail matrix
Active growing part
Hair
Flexible strand of dead cells filled with keratin
Root and shaft
Melanocytes at base of hair follicle - different proportions in types of melanin give colours
Stem cells found in external root sheath
Round hair shaft
Straight hair
Oval hair shaft
Wavy hair
Flat hair shaft
Kinky hair
Grey hair
Decreased melanin and colourless air bubbles
Hair follicle
Hair bulb and hair follicle receptor
Stem cells found in external root sheath
Hair papilla with capillaries
Arrector pili
Raiser of hair, goose bumbs
Small muscle from follicle to epidermis
Sebaceous glands
Oil glands of skin
Associated with hair follicles
Secretion soften and lubricates hair and skin
Holocrine secretion: miniature explosion, death of cell
Acne
So much sebum: blocks the gland
White head is oxidized to black head
Infected sebaceous glands give pimples
Burns
Tissue damage due to heat, electricity, radiation, extreme friction, chemicals
Infection or dehydration
First degree burn
Damage to epidermis
Redness, swelling, pain
Second degree burn
Damage to epidermis and upper dermi
Blisters
Third degree burn
Entire thickness of skin
White, red or black discolouration
Autograft required
Autograft
Skin from other parts of patients body grafter to burned area
Artificial skin
Skin made from bovine collagen dermis and epidermis made of silicon
