Integumentary System

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Integumentary System
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(Hypodermis)
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• Integumentary System

• Skin
• Hair
• Nails
• Associated Structures (vessels, nerves, glands)

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Membranes

• Epithelial membranes
• Cutaneous
• Mucous
• Serous
• Parietal vs visceral
• Pleura, pericardium, peritoneum

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• Integumentary System

• Skin (cutaneous membrane)
• Main layers superficial to deep
• Epidermis
• Dermis
• Hypodermis
• -not always
• considered
• part of skin

(Hypodermis)
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• Functions of Skin

• Protection
• Sensation
• Movement without energy
• Excretion
• Vitamin D production needed to absorb calcium
• SunSkin Vit D blood kidney/liver
  calcitriol blood regulates calcium
  phosphorous
• Immunity
• Healing Wounds
• Body temperature homeostasis
• vasoconstriction vasodilation

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• Skin Structure

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• Epidermis

• Epidermis outer layer
• Keratinized stratified squamous epithelium
• Avascular (hardened by keratin)
• Renews itself every 45 days

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• Epidermis cell types

• Keratinocytes
• produce keratin waterproofing protein
• Originate in deeper layers get pushed to
  surface becomes keratin filled dies
• Connected to each other by desmosomes tight
  junctions
• Cell production keratinization are accelerated
  in areas of friction
• Callus thickened skin

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• Epidermis cell types

• Melanocytes
• Produce melanin
• Prevents DNA mutation from the UV radiation
• UV increases melanin production
• Same number in everyone, but different amount of
  pigment produced
• Accumulation of melanin results in freckles and
  moles

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Epidermis Skin Color

• Determined by three factors
• Types of pigments present
• Melanin brown, black, or yellow pigment
• Carotene
• Hemoglobin
• Blood circulation
• Stratum corneum thickness

• Orange-yellow pigment from some vegetables
• Vitamin A precurser vitamin A forms retinal
  which is needed for sight
• Accumulates in adipose and stratum corneum cells

• Red, oxygen-carrying pigment in erythrocytes
• More obviously detected in fair skin

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• Skin as a Diagnostic

• Skin color is influenced by emotional disease
  states You should know the states that cause
  these.
• Cyanosis bluish color - lack of oxygen
• Erythema redness heat, inflammation, fever
• Albinism genetically black, but white no
  melanin produced from melanocytes
• Pallor paleness lack of blood flow
• Jaundice yellowish color liver damage
  accumulation of bilirubin
• Bronzing bronze (tan) Addisons disease
• Hematomas black blue blood under skin

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• 5 strata of the Epidermis Deep to Superficial

• Stratum basale
• highly mitotic (produces new skin layer)
• 25 melanocytes
• Stratum spinosum
• Slightly mitotic
• Contains Langerhans macrophages
• Several layers of many sided cells (looks spiny)

• Stratum granulosum
• Also contains Langerhans cell
• contains keratohyalin (helps form keratin)
• Stratum lucidum
• ONLY found in thicker epidermis palms, soles,
  callus
• Completely keratinized (and dead!)
• contains closely packed, clear cells that contain
  gel-like substance eleiden

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• 5 strata of the Epidermis

• Stratum corneum
• Outermost layer
• Also completely keratinized
• Dead cells
• Tough, waterproofing protection

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• Dermis

• Middle layer of skin
• Contains hair folllicles, glands, nerves,
  vessels, muscle
• All four tissue types present
• Mainly strong, flexible CT - Two layers

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• Dermis

• Papillary layer
• Contains Areolar CT
• Dermal papillae
• Indent into epidermis
• forms fingerprints
• Important for grip
• Contains blood vessels
• Meissners Corpuscles nerve (touch) receptors

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• Dermis

• Reticular layer
• Dense irregular CT
• contains blood vessels, nerves, glands, adipose
• Pacinian Corpuscles nerve endings responsible
  for sensitivity to deep pressure touch and high
  frequency vibration
• Collagen prevents overstretching and tearing of
  skin
• Elastin allows skin to stretch
• stretch marks dermal tears

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• Hypodermis

• Not usually considered part of the skin
• Also called subcutaneous layer
• Site of subcutaneous injections absorbed
  directly into blood stream
• Anchors skin to underlying organs, shock
  absorption, insulation
• Composed mostly of adipose tissue
• Very vascular

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Skin Appendages
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• Appendages of the Skin

• Hair
• Minor protective functions (retain heat, decrease
  sunburn, eyelashes protect eyes)
• Structure
• shaft projects from skin
• follicle extends into dermis
• root lies within the follicle
• bulb contains CT, vessels and nerves
• sebaceous gland lubricates hair
• arrector pili muscle attached to follicle and
  contracts to move hair (hair growth, goosebumps)

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Hair
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• Appendages of the Skin

• Hair Growth
• influenced by (in this order)
• nutrition - main influence
• hormones
• blood flow
• baldness ( alopecia )
• male pattern baldness - sex linked recessive
  genetic trait
• thinning can be caused by medications,
  nutrition, stress, etc.

• Hair Pigment
• caused by proportions of 3 melanin types
• dark hair true melanin
• blonde and red melanin with iron and sulfur
• gray/white hair - melanin replaced by air bubbles
  in shaft

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• Appendages of the Skin

• Nails
• Scale-like modifications of the epidermis
• Heavily keratinized
• Stratum basale extends beneath the nail bed to
  form nail matrix
• Responsible for growth ( matrix region)
• Lack of pigment makes them colorless
• Lunula little moon area of cell growth (white
  semicircle at base of nail)
• Cuticle area of skin that covers base of nail

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• Nail Structures

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• Sweat Glands

• Eccrine glands
• Widely distributed in skin abundant on palms,
  soles, forehead
• Sweat composition mostly water with a slightly
  acidic 4-6 pH
• Function thermoregulation

• Apocrine glands
• Ducts empty into hair follicles
• Found mainly in anogenital axillary region
• Begin to function at puberty due to hormones /
  pheromones
• Organic contents Fatty acids and proteins can
  have a yellowish color that stains clothes
• Odor is from associated bacteria

• Ceruminous glands
• Modified apocrine gland
• Found in outer 1/3 of ear canal
• Produce ear wax to trap invaders

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• Appendages of the Skin

• Sebaceous glands
• all over except palms and soles of feet
• Produce oil for waterproofing
• Lubricant for skin kills bacteria
• Most with ducts that empty into hair follicles
• Glands are activated at puberty stimulated by
  hormones
• Acne active infection of sebaceous glands

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Burns
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• Burns

• Protein denaturation and cell death caused by
  heat, electricity, UV radiation, or chemicals
• 2 main dangers
• DehydrationLoss of fluids Electrolytes lead
  to
• Renal Shutdown
• Circulatory shock
• Infection
• Skin (mechanical) barrier lost
• Immune system depresses

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• Rules of Nines

• Way to determine the extent of burns
• Primary importance is to estimate fluids needed
  for rehydration
• Body is divided into 11 areas for quick
  estimation
• Each area represents about 9

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Rule of nines diagram
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• Partial Thickness Burns

• First-degree burns
• Only epidermis is damaged
• Local redness, swelling, pain
• Usually heal in 2-3 days (short time period) with
  NO scarring

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• Partial Thickness Burns

• Second degree burns
• Epidermis and dermis structures within dermis
  are damaged
• Appearance of blisters of any size
• Skin regeneration in
• 3-4 weeks with some scarring
• There is a danger of infection

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• Full Thickness Burns

• Third-degree burns
• Epidermis, Dermis, Hypodermis and all structures
  within are completely destroyed
• Usually painless at site of burn due to
  destruction of sense receptors
• Burn is gray-white, tan, brown, black, or deep
  cherry red
• Surrounded by areas of 1st 2nd degree burns
  that will be painful
• Treatments are numerous but will involve skin
  grafting of some sort, fluid replacement and
  debridement

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All degrees of burns
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Skin Cancer

• Skin cancer is the most common type of cancer
• 2 out of 5 cancers are skin cancers

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• Skin Cancer

• Cancer uncontrolled cell growth
• Caused by damage to the DNA usually through
  chemicals or radiation
• Two types
• Benign
• Does not spread (encapsulated)
• Malignant
• Metastasized (moves) to other parts of the body

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• Skin Cancer Types

• Basal cell carcinoma
• Least malignant
• Most common type (90 of skin cancers)
• Arises from stratum basale
• cannot produce keratin
• Boundary lost between dermis and epidermis
• Seldom metastasizes treated surgically or by
  radiation 99 cure rate if caught early
• Signs
• Pale marks
• Reddish patches
• Round, smooth growth with raised edge
• Shiny bumps
• Sores that dont heal

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Basal Cell Carcinoma
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Basal Cell Carcinoma
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• Skin Cancer Types

• Squamous cell carcinoma
• 2nd most common skin cancer
• Highest risk fair skin, light hair, blue/green
  eyes
• Arises from stratum spinosum
• Metastasizes to lymph nodes if left untreated
• 1500-2000 deaths in US per year
• Early removal allows a good chance of cure
• Signs are same as basal cell carcinoma

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Squamous Cell Carcinoma
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Cumulative Effects

• IMPORTANT TO KNOW
• Basal cell squamous cell carcinomas are due to
  cumulative effects of the suns radiation (or
  chemical exposures as well)
• These tend to develop in ages 30-40s after years
  of daily sun exposure

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• Skin Cancer Types

• Malignant melanoma
• Least common
• most deadly of skin cancers
• Originates melanocytes
• Metastasizes rapidly to lymph and blood vessels
• Early detection is critical see notes for
  survival rates

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Intensive Effects

• Malignant Melanoma tends to occur in younger ages
  (as well as older people)
• It is due to brief intense exposures (aka
  sunburns)
• This is the most serious form of skin cancer and
  MUST be caught early to be treated successfully!

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• ABCD Rule

• A Asymmetry
• Two sides of pigmented mole do not match
• B Border irregularity
• Borders of mole are not smooth
• C Color
• Different colors in pigmented area
• D Diameter
• Spot is larger then 6 mm in diameter (pencil
  eraser)
• Mole starts growing/changing in size

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Malignant Melanoma
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Melanomas
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Melanomas
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Prevention

• Wear sunscreen whenever outside or cover up
• avoid midday sun between 10-2 and beware of
  reflected light
• higher altitudes - every 1000 ft above sea
  level, radiation increases 4-5
• Be cautious about tanning beds
• Medications - tetracycline (antibiotics), Retin
  A, birth control, antidepressants,
• diuretics, and anti-inflammatories cause
  photosensitivity
• avoid sunburns
• examine skin regularly - remember ABCD rule
  have full body check by dermatologist once a year

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Other Integumentary System disorders
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• Contact dermatitis (Ezcema)
• Exposure to allergen/irritant (ie. poison ivy)
  cause allergic reaction
• inflammation, red, itchy skin
• not contagious
• over the counter meds sometimes Rx
• Prevention by avoiding allergen/irritant
• Blisters
• Epidermal cell injury or separation of epidermis
  from dermis
• Warts
• Benign neoplasms, but can turn malignant
• Contagious
• Remove by freezing, drying, laser therapy,
• chemicals
• Boils
• Bacterial infection that infects hair follicles
• Large, inflamed, pus-filled lesions

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Tinea Fungal infections (ringworm, jock itch,
athletes foot) Reddish discoloration, scaling,
crusting Treat with antifungal agent Prevent
recurrence by keeping skin dry Impetigo
Caused by bacterial infection Mostly
children Reddish discoloration turns into
blisters and yellowish crusts If turns
systemic, it is life threatening
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Psoriasis Cause is unknown, probably
genetic Triggered by trauma, infection,
stress Cutaneous inflammation, scaly lesions
Due to excessive rate of epithelial cell
growth Urticaria Hives Raised, red lesions
caused by blood vessel leakage Severe
itching Causes (hypersensitivity, allergic
reactions, physical irritants, systemic
disease) Scleroderma Autoimmune Affects blood
vessels and CT Hard skin lesions More common in
women Decubitus ulcers bedsores / pressure
sores Lack of blood flow causes tissue damage
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Acne Clogged sebaceous follicles from
abnormal shedding of skin cells Bacteria
build-up in sebaceous glands Enhanced by
hormones Over the counter meds sometimes
Rx Prevention -avoid using oils, greasy
moisturizers, facewash, and makeup -wash hands
before applying makeup -use non-scented
ordinary mild soap -keep hands away from face