Integument
Integument System
MJM
One of the largest organs ~ 2/3 size of the liver
Receives up to 1/3 of blood supply
Layers
epidermis
Site of fluid accumulation in blisters
Dermal papilla - nipple-shaped mound
dermis
hypodermis
fascia or periosteum
Functions
1. Physical protection from environmental hazards, influences, water, disease, chemicals
2. Protect from excessive water loss
3. Regulate body temperature
4. House sensory receptors
5. Excretion of waste materials
6. Synthesis of vitamin D3
7. Synthesis and storage of lipid reserves
8. Coordinate immune response to pathogens and cancers in skin
Epidermis - Stratified squamous epithelium
0.1 to 1mm thick (due to pressure, rubbing and other mechanical factors
palms of hands and soles of feet thick in the foetus
Layers
1. Stratum germinativum - basal layer, cell division with many mitotic figures. Attach to basal lamina. Contain epidermal stem cells, melanocytes 1:4 - 1:20 ratio, and Merkel cells (Pressure sensitive, release chemicals to stimulate neurons when "pushed". Langerhans cells to initiate immune response against pathogens.
2. Stratum spinosum - cells pull apart, thin "spiny" interconnections, Keratinocytes are bound together by desmosomes attached to tonofibrils of the cytoskeleton
3. Stratum granulosum - Keratinocytes produce keratohyalin and keratin. Keratin fibers develop as cells become thinner and flatter. Gradually, the cell membranes thicken, the organelles disintegrate, and the cells die
4. Stratum lucidum - granules fuse, appears "glassy", cells become further elongated, nucleus shrinks.
5. Stratum corneum - no nucleus, keratin predominate, multiple layers of flattened, dead, interlocking keratinocytes, typically relatively dry, water-resistant, but not waterproof, permits a slow water loss by insensible perspiration.
Skin color due to combination of blood supply, melanin, and carotene. Melanocytes stimulated by sun's UV light, causes tyrosinase to oxidize tyrosine to form melanin.
Dermis - Consists of CT, collagen and elastic, BVs, 3 mm thick (soles of feet) 0.5 mm in the eyelid.
Hypodermis - beneath dermis, CT varies in fat cell content, attachment to deeper layers.
Eyelids -without hypodermis containing fat
Fat content important in transplants.
Hair
1. Vellus hairs - fine "peach fuzz" over much of body
2. Intermediate hairs - hairs of upper and lower limbs
3. Terminal hairs - heavy, pigmented, curley hairs of head
Hair cycle
Eyelash - 2 - 4 months
Head - 2 - 5 year cycle
Associated hair structures
1. Arrector pili muscle
Straighten hair
Squeeze ducts
Cause goose pimples
2. Sebaceous glands - ducts into follicle
Oily secretions for:
Moistness
Prevent heat loss
Prevent excessive water loss
Sudoriferous or eccrine sweat glands - none on lips, male penis, or nail bed.
Simple tubular gland- enter at peak of ridge in hands and feet
Myoepithelial cells - modified muscle cells adjacent to glands to help excrete fluid.
Two million per person
700 - 900 ml per day (average)
Apocrine - Axillae, nipple areolae, groin
External auditory meatus - modified sweat glands - cerumen and lipid
Mammary glands
Eyelids - Moll's glands - open into follicles of eyelashes
Sensory Receptors - Receptive Fields
Free nerve endings - pain, temperature, and hairs
Merkel's (tactile) disk - fine touch s. germinativum
Miesner's corpuscles - Light touch d. papilla
Ruffini corpuscles - Skin pressure/distortion
End Bulbs of Kraus - cold
Pacinian corpuscles - deep pressure
Nails
1. Nail bed
2. Nail wall - skin around the nail
3. Nail groole - between skin and the nail, eponychium and hyponychium
4. Nail - tightly packed keritinized epithelial cells, have higher sulfur content
5. Lunula - white of nail/growth point. - 1 mm/week
BURNS
First Degree - Epidermis
Second Degree - Dermis
Third Degree - Epidermis and Dermis
Growth
Sides
Germinal Structures
Transplants
Rule of Nines
9 % each
Head
Right anterior trunk
Left anterior trunk
Right posterior trunk
Left posterior trunk
Arm
Anterior leg
Posterior leg
1 % - Inguinal region
WOUND HEALING
1. Blood clotting
2. Vasodilation
3. Macrophage migration
4. Debris removal
5. Fresh capillary buds
6. Migration of
Fibroblasts
Blood vessels
CT formation
7. Epithelium regeneration
CONDITIONS OF CLINICAL SIGNIFICANCE
Acne - Bacterial (rod) provocation
- Excess secretion by sebaceous glands
Warts - Viral invasion of skin
Dermatitis and Eczema
Inflammatory skin conditions
Nonspecific allergenic responses
Psychosomatic condition -
Site of expression of stress-induced imbalances
Low protein diet
Black current oil (GLA - gamma linolenic acid)
Poultice of Chaparral (Larrea divaricata)
and Calendula lotion and aloe
Psoriasis
Small reddish-brown elevations
Bleed when scraped from tops of papillae
Skin cells mature too rapidly
- in only three or four days instead of 28
- abnormal cells build into inflamed,
elevated lesions
- become covered with dead skin (scales)
Treatment
moisturizers
mild soaps
corticosteroid creams
phototherapy
UV light
psoralen
Healthy diet - immune response
Contraindicated - ethanol
National Psoriasis Foundation
6600 Southwest 92 nd Ave. Suite 300
Portland, Oregon 97223 800-248-0886
Sty - Infection of gland at the root of an eyelash
Acute, painful inflammation
Contagious, may be spread
Chalazion - meibomian cyst
Swelling of eye lid gland
Oily secretion to
Lubricate
Protect
Secretion thickens and clogs duct
Infection causes red, sore eyelid
Non-contagious
Treatment
Warm compresses
Steaming
Antibiotics
Draining
Impetigo - contagious
Staphylococcus
Streptococcus
Moles
Pigmented skin growths
Can become malignant
ABCs
Abnormal growth
Border ragged
Color changes
Herpes Simplex
Viral infection of nerves
Manifests as blisters at papillary layer
Herpes Zoster (Shingles)
Similar to chicken pox
Blister around torso
Cancer
Epidermis
Dermis
Sudoriferous
Sebacious
Heat Stroke
Loss of water
Loss of electrolytes
Regulation of body temperature