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What are the functions of Skin?
- 1. Protection
- 2. Body Temperature regulation
- 3. Cutaneous Sensation
- 4. Metabolic Function
- 5. Blood Reservoir
- 6.Secretion
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What are the regions of the skin?
- Epidermis
- Dermis
- Hypodermis
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Epidermis
- The outermost layer
- Keratinized, stratified squamous epithelium
- Keratin makes it stronger/tougher
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Dermis
- 2 different types of connective tissue
- Connective Tissue Proper
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What are the 4 different types of cells that make up the Epidermis?
- Kerantiocytes
- Langehens Cells
- Merkel Cells
- Melenocytes
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Kerantiocytes
- Produces Keratin(Makes cells tough/hard)
- Connected by desmosomes
- Arises from a deeper mitotically active layer
- Dead at Surface
- ONLY CELL IN EPIDERMIS THAT REGENERATE
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Langehens Cells
- Resident Macrophage Cells(White Blood Cells)
- Active Immune Systems
- Initiate the immune response
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Merkel Cells
- This is the receptor for touch.
- It is located at the epidermal junction.
- More in fingers, less in back
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Melenocytes
- Synthesizes Melanin (Give you skin color)
- Found in deepest layer
- Amount of Melanin determines color
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What are the layers of the Epidermis in order?
- Stratium Basale
- Stratium Spinosum
- Stratium Grulosum
- Stratium Corneum
- Stratium Lucidin
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Stratium Basale
- Deepest layer, attached to dermis
- Single Row of youngest keratinocytes
- Melanocytes Cells
- Uses most of energy
- Skin Color orginates in this layer
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Stratium Spinosum
- Several Layers thick
- Irregular shaped Keratinocytes
- Attached by desmosomes
- Starting to produce Keratin
- Still use a little energy
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Stratium Grulosum
- 3-5 Layers Thick
- Organelles are depleted
- Cells begin to die
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Keratohyaline Granules
- Help form keratin in upper layers.
- Located in Stratium Grulosum
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Lamellated Granules
- A cell that contain a water resistant glycolipid that is spewed in the extra cellular space and is a major factor in slowing water loss across the Epidermis.
- Located in Stratium Grulosum
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Stratium Corneum
- 20-30 layers thick
- Glycolipid between cells(Help skin be waterproof)
- Washed a little away everyday
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Stratium Lucidin
- ONLY IN THICK SKIN
- Single cell layer thick
- Only found in palms and soles of feet
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2 layers of the Dermis
- Papillary Layer
- Reticular Layer
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Papillary Layer
- Loose Areolar Connective Tissue
- 20% of the Dermis
- Dermal Papillae
- It is loose to allow phagocytes and other defensive cells to move around to protected the body from bacteria that could have possible gotten past the epidermis.
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Reticular Layer
- 80% of the Dermis
- Dense irregular connective Tissue
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Dermal Papillae
- The indent the overlying epidermis
- Some contain capillary loops and some contain touch receptors.
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Elector Fili Muscle
Makes the hair stand up on end goose pimples
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Friction Ridges
Increase friction and enhance the gripping ability of the fingers and feet.
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Clevage Lines
Collagen Fibers arranged in bundles form cleavage(Tension Lines)
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Eccrine Sweat Glands
- Most Abundant gland
- Not prominent in children
- High density on palms, side of feet and forehead
- Secrete sweat
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Sweat
- Hypotonic blood filtrate
- 99% water, some NaCl and other materials
- Acidic(pH 4-6)-Used to help with bacteria control
- Thermoregulation
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Apocrine Sweat Glands
- Sex hormone stimulates this gland so not present until puberty
- Converted to axially(armpit) region and anal genital area
- Larger then Eccrine Gland
- Higher Lipid content- leads to milky color and body odor from bacteria.
- Creates sexual arousals
- Similar to sexual scent gland-sexual foreplay increases activity
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Mammary Glands
- Creates Milk
- Men have these glands they just don't work.
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Serimincous Glands
Makes Earwax(Helps keep bugs away)
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Sebuceous Glands(Oil)
- Puke to skin soft and smooth
- Alveolar gland(everywhere but the palms and soles of feet)
- Secretes Sebum
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Sebum(Holocrine)
- Lubrication-helps hair from getting matted up
- Skin-slows waterloss
- Hair-prevents brittleness
- Bacterial Function-kills bacteria
- Stimulated by androgens(more abundant after puberty)
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Acne develops:
- Hair follicles become plugged: sebum and dead skin follicle
- Bacteria is then triggered leading to inflammation, infection
- Once the inflammation response occures white blood cells are sentand this cause the puss.
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Reasons for Hair
- Nerve endings help us preserve our environment, insect, or wind.
- Hair protects from sun.
- Hair distributed over entire skin expect soles of feet, palms, lips, nipples, and portions of external genitalia.
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3 Layers of Cells for Hair
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Medulla
- Cell of Hair
- No Hard Keratin; only terminal hair has Medulla
- Not found in fine hairs
- Only part with soft keratin
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Cortex
- Cell of Hair
- Tend to be thick
- Moderately hard keratin
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Cuticle
- Cell of Hair
- Completly made of keratin
- Outer layer
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What are split ends?
The cuticle has been removed and the cortex and medulla has begun to unravel.
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Review Hair Bulb In Notes and Book
REVIEW HAIR BULB IN NOTES AND BOOK
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Terminal Hair
- Thick Hair
- Hair on head
- Eye Brows
- Visible
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Vellus Hair
- Thin Hair
- Doesn't develop or grow
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Growth of Hair
- 2.5 mm per week
- Activate/Dormant(fall out)
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Loose about ________ per day
_____________ have stay longer, so not as many fall out
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Alopecia
- Hair Thinning
- Age related hair loss
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Baldness
- Generally determined and sex altered
- Male Pattern baldness-caused by follicular response to DHT(high levels of DHT)
- Passed by mom(sex-linked) have to have trait for it
- Makes hair follicular sensitive; makes hair follicles to be dormant usually they have very short life cycle for the hair.
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Basal Cell Carcinoma(Skin Cancer)
- Least malignant; most treatable; this is the one u want to get.
- Stratum basal cells proliferate and invade dermis
- Sun exposed area more common
- Usually a slow growing type of cancer
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Squamous Cell Carcinoma (Skin Cancer)
- Keratinocyte of the stratum spinosum
- Will start with what looks like a mole, but is more rapid than basal cell
- Grows rapidly, metastasizes, good outcome if caught early(enters the blood stream and goes somewhere else)
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Melanoma (Skin Cancer)
- Most dangerous, highly metastasize, chemotherapy resist
- Cancer of melanocytes
- 1/3 from pre-existing moles
- Start at basal layer epidermis; don't see it before it has already has spread
- Spreads laterally, then down before it grows up and can be identified
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ABCD Rule of Thumb Identifing Skin Cancer
- Asymmetry- 2 sides don't match; unusual, not uniform
- Border Irregular-indentions in border; tent to have a distinct pattern
- Color-pigmented spots contain different colors; not uniform in color
- Diameter- longerthan 6 mm diameter
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1st Degree Burn
Only the epidermis is damaged
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1st Degree Burn Symptoms
- Localized redness
- Swelling pain
- Some peeling a few days later
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2nd Degree Burn
Epidermis and upper dermis are damaged.
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2nd Degree Burn Symptoms
- Localized redness
- Swelling pain
- Some peeling a few days later
- BLISTERS(fluid accumulation)
- Swelling
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3rd Degree Burns
- Entire thickness of the skin is damaged, getting into deeper tissue.
- Can't regulate temperature in burnt area because the loss of sweat glands
- Charring is also accompanying the skin next to the burn.
- Dehydration is the 1st thing to worried about
- Infection is next: will happen the next 12 to 24 hours
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3rd Degree Burns Symptoms
- Burn appears gray-white, cherry-red, or black
- There is no initial pain or edema
- Have to get a skin graft(To completly heal)
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Rules of Thumb for Burns(Burns are critcal if:)
- Over 25% of body has 2nd degree burns
- Over 10% of body has 3rd degree burns
- There are 3rd degree burns on face, hands and/or face
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Rules of Nine
- Tool to estimate body fluid loss
- 1%-Private
- 9%-Front of Legs
- 9%-Back of Legs
- 9%-Whole Arms
- 9%-Anterior of Front
- 9%-Posterior of Back
- 9%-Head
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Types of Skeletal Cartilage
- Hyaline
- Elastic
- Fibrocartilage
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Hyaline
- Provides support but is flexible
- Most abundant
- Good at withstanding comprising forces
- Located on long bones to decrease friction
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Elastic
- Withstands repeated stretching
- Located in the ear and epiglottitis
- Can be stretch and returned back to original shape
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Firbrocartilage
- Compressible with a high tensile strengeth
- Located mostly where we have compression
- Acts as a cushion
- More dense than hyaline
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Appositional Growth(Outside)
Cartilage Growth
- Cartilage forming cells secrete new matrix an external face;
- Chondroblasts(can lay down cartilage)
- Become a chondrocytes when their is a high number in the lacunae.
- Laying down new cartilage as well as laying down ground substance.
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Interstitial Growth(Outside)
Cartilage Growth
- 1 Mature chondrocytes secrete matrix
- Lays down limited amount of cartilage and ground substance
- Limited amount of growth
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Bone Functions
- Support
- Protect
- Movement
- Mineral Storage
- Blood Cell Formation
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Groups of Bones-2
- Axial Skeleton
- Appendicular Skeleton
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