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Integumentary system
Function Of Skin
• Protection - Prevent drying (lipids), outside
agents from inside (barrier and pH), UV rays
(melanin)
• Body temperature regulation
(Thermoregulation) – Dilation / contraction of
blood vessels, sweating
• Sensation - Receive sensory informationreceptors for temperature and pressure
• Secretion – sebum, excretion too – sweat,
vitamin D production due to UV rays (low
dose)
Keratinization
• Skin cell process of being keratinized;
newly formed cells in the stratum
germinativum divide and push upward to
the surface, they fill up with keratin, a
protein. They move upward and lose their
nucleus and die. The cells become horny.
Takes 28 days.
Structure Of Skin
Structures
• Epidermis-Top Layer, Stratified Squamous epithelial, no blood
vessels, diffusion (O2 , nutrients) Has five layers:
• Stratum Corneum- (horny Layer) outer layer. Scale like cells (dead)
that continually shed. barrier
• Stratum lucidium- (clear Layer) transparent layer under the stratum
corneum. Small cells that light can pass through.
• Stratum Granulum (granular layer) layer, the cells look like distinct
granules. The cells are almost dead (keratinization), they are
pushed to the surface to replace the cells that were shed from the
stratum corneum. Lost nuclei and become brittle.
• Stratum spinosum – (spiny lavers) desmosomes – interlocking
cellular bridges, polyhedron shape.
• Stratum Germinativum – (regenerative layer) Basal, deepest layer.
Responsible for the growth (mitosis) of the epidermis. Melanocytes –
skin color
Skin structure picture con’t
Structures
• Dermis- Corium, true skin, Middle Layer, Dense
connective tissue, blood, lymph vessels, nerves,
muscles, glands, hair follicles, papillar below
epidermis, reticular above subcutaneous
• Hypodermis / subcutaneous- Bottom layer, Adipose
• Sebaceous Gland- Oil, Near hair, rich in lipids
• Sudoriferous- Sweat, pore to outside, water and salt
• Arrector Pili- Smooth muscle, Contracts to form
goose bumps (hair stands on end)
• Nerve- Pain, Pressure, temperature
Sebaceous gland
• The Sebaceous gland is an oil gland. It is
connected to the hair follicles. Everywhere
on your body has an oil gland except for
your palms and the soles of your feet.
Sebum flows through the oil ducts leading
to the mouths of the hair follicles. Sebum
lubricates and protects hair / skin. Acne –
pore clogged with sebum. Oxidizes –
blackhead, Pus filled – white head /
pimple. Deep clog – boil,holocrine
Sudoriferous gland
• The sudoriferous gland is a sweat gland. 2
types: Eccrine – produce sweat, Apocirne –
body’s natural scent. Both merocrine All the
parts of your body have sweat glands. It
regulates body temperature. The excretion of
sweat is controlled by the nervous system.
Sweating is important for survival because it keeps
temperature from going really high. It allows the body
to be cooled by the evaporation of sweat.
• Some things that can make your temperature
go high is: Exercising ,Being sick
Skin coloring differences
• Skin Differences
The color differences depend primarily on the
amount of melanin (blood supply too). The tiny
grains of pigment (melanin) deposited in the
stratum germinativum of the epidermis and the
papillary layers of the dermis. The color of
pigment varies from person to person. The
distinctive color of the skin is a hereditary
(genetic) trait and varies among races and
nationalities. Dark skin contains more active
melanin; Albinism, genetic, absence of melanin.
Skin Coloring
• Melanin- Pigments responsible for coloring, Protects
from UV light
• Albinism- Lack of Melanin, Genetic
• Carotene- Yellow pigment, Source of Vitamin A, Skin
yellow by consumption
• Cyanosis- Bluish color, Lack of O2
• Birth Marks- congenital (at birth), Disorder of blood
vessels in dermis
• Jaundice – yellow skin (billirubin build up) impared
liver function
• Rash / lesion – Scarlet fever, strep infection due to
toxins released allergic reaction
HAIR STUCTURE
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12 = scales / cuticle
13 = cortex
14 = medulla
15 = melanocytes
16 = keratinocytes
17 = dermal papilla
Hair- Trichology
• Main characteristic of mammals, none palms,
soles ,external genitalia
• Shaft- Hair above the surface
• Roots- Below the surface
• 3 Layers of hair- Cuticle (outer layer,), Cortex
(hard inner layer, pigment), Medulla (soft
center)
• Hair Follicle- Where hair is found in dermis
• Dermal Papilla- Blood vessels provide hair
with nutrients to grow
Anatomic parts of hair
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Cortex
Cuticle
Medulla
Hair root
Hair shaft
Follicle
Hair bulb
Dermal papilla
Arrector pilli
Sebaceous gland
Hair Growth
• Begin with cells deep in follicle at bulb
growing by mitosis
• Anagen- Growth phase, hair makes new
keratinized cells, ½ an inch per month,
3-5 years
• Catagen- The transition phase, the
follicle shrinks and detaches from
papilla(1-2 Weeks)
• Telogen- Resting phase, hair is shed(36 Months)
• Entire Cycle- Every 4-5 years
Hair texture
• Straight, wavy or curly (kinky)
• Alpha keratin cross links.
• Permanent wave: Chemical reducing
agent break disulfide bonds, chemical
oxidizing agent make new cross links.
Hair color
• Pigment in cortex give the colors
• Gray – lack of pigment in cortex
• White – no pigment and air bubbles in
shaft
• Trauma – cause premature gray / white
Nails- Onyx
• Nail Bed- Nail attaches to skin
• Nail Root-(Matrix) where nail is formed
• Lunula- white cresent, half-moon,
visible matrix, air mixed with keratin
• Nail Body- Plate- visible part of nail
• Cuticle- Overlap skin (stratum
corneum) around the nail, eponychium
• Grows 1/8 in. per month, grows
continuously, no resting stage
NAIL STRUCTURE
Disorders
• Acne- Disorder of the hair follicle and
sebaceous gland
• Impetigo- Bacteria making blisters that break
to form a yellow crust
• Measles- A rash, by virus, damage fetus
• Cold Sores- Herpes simplex 1, Virus
• Warts- Uncontrolled growth of epidermis
papilloma virus
• Ring Worm- Fungal infection, scaly patches
Disorders
• Eczema- Inflammation of the skin
• Psoriasis- Increase cell division in the
stratum basal, thicker skin
• Chicken Pox/Shingles- Virus, remains
dormant with the nerve cells, painful lesions
along dermatones
• Dandruff (Pityriasis)- Excessive shedding of
epithelial cells
• Lice (Pediculosis)- Itching, slight rash
• Vitiligo – irregular patches of skin lacking
pigment.
Burns description
• First Degree- Only epidermis, red painful,
slight edema (swelling) Heal without
scaring in a week, sunburn
• Second Degree- Into the dermis, blisters,
epidermis from hair follicle
• Third Degree- Tissue completely
destroyed, Heals from edge of burn,
painless because receptors are damaged,
scaring, sometimes skin graphs
Burns diagrams
Aging
– Skin becomes thinner
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Loss of elasticity
Wrinkles sagging
Less oil and sweat production
Age spots – loss of melanocytes
around it
• Gray in hair – lack of melanin
Wrinkles
Cancers
• Uncontrolled growth
• Skin cancer (most common type)
• Basal Cell Carcinoma- (Most frequent)
Stars in Stratum Basal
• Squamous Cell Carcinoma- Cells above
stratum basal- Keratin bumps
• Melanoma- Rare but deadly in
melanocytes- in a mole (group of
melanocytes)
Skin cancers
Skin cancers