What is the integument formed by?
skin, hair, nails, sweat and oil glands
What are the layers of the skin?
Epidermis, dermis, and hypodermis
What is the epidermis (stratum corneum) and what defenses does it provide?
- A thick layer of epithelial cells, packed w/ keratin giving the cells the ability to withstand damage and abrasion.
- Lipids are packed b/t cells giving them water-repelling properties
- It is replaced entirely every 25-45 days
- It contains a basal layer which is the source for all the cells making up the epidermis
What is the dermis and what defenses does it provide?
- Composed of connective tissue w/ a rich matrix of fibroblast cells and fibers like collagen. It harbors a dense network of nerves, blood vessels, and lymphatic vessels w/ damage causing the dermis to bleed.
- Blisters form as a result of friction trauma or burns, leading the dermis and epidermis to separate.
- Defenses include follicles, sweat gland, sebum, sweat, and lysozyme
- Antimicrobial peptides are also a defense BUT they are in both the dermis and epidermis
The defenses of the skin include:
- keratinized surface: creates water resistant barrier
- sloughing: continuous shedding of dead skin cells
- follicles: root of hairs containing sebaceous (oil) and scent glands
- sweat glands: separate from follicles, producing sweat w/ low pH and high salt concentration inhibiting microbes
- antimicrobial peptides: positive charged chemicals disrupt negatively charged bacteria membranes
- sebum: secreted by sebaceous gland creating low pH, high lipid concentration, and toxic by-product via fatty acids breakdown
- lysozyme: enzyme in sweat, tears and saliva that breaks down peptidoglycan
Which microbes make up the normal biota?
bacteria, viruses, archaea, fungi, and protists/protozoa
Bulla
large (wide) vesicle
Cyst
raised lesion that is encapsulated and usually solid or semisolid
Macule
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Maculopapular rash
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Papule
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Petechiae
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Plaque
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Purpura
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Pustule
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Scale
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Vesicle
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Staphylococcus aureus
- gram-positive coccus forming grape clusters, nonmotile and sturdiest of all non-endospore forming to withstand high salt, extremes in pH and high temps and viable after months of air drying.
MRSA (Methicillin-resistant Staphylococcus aureus) Skin and soft tissue infection
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Impetigo (Staphylococcus aureus)
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Impetigo (Streptococcus pyogenes)
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Cellulitis (MRSA)
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Cellulitis (Streptococcus pyogenes)
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Cellulitis (other bacteria or fungi)
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SSSS (Staphylococcal Scalded Skin Syndrome)
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Gas Gangrene
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Chickenpox
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Smallpox
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Hand, Foot and Mouth Disease
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Measles (Rubeola)
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Rubella
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Fifth disease
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Roseola
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Warts and Wartlike Eruptions (human papillomaviruses)
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Warts and Wartlike Eruptions (Molluscum contagiosum viruses)
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