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The Integumentary System
The Integumentary System
• Organ system that protects the body from various kinds
of damage
• Examples: water loss, abrasion
• Includes skin and its derivatives
• Hair
• Nails
• Glands
• Sebaceous
• Sudoriferous
• Ceruminous
• Scales, feathers, hooves in other animals
Structure of the Skin
• One of the body’s largest organs
• 2 main layers
• Epidermis
• Dermis
Copyright © 2010 Pearson Education, Inc. Figure 5.1
Epidermis
Hair shaft
DermisReticular
layer
Papillary
layer
Hypodermis
(superficial fascia)
Dermal papillae
Pore
Subpapillary
vascular plexus
Appendages
of skin
• Eccrine sweat
gland• Arrector pili
muscle• Sebaceous
(oil) gland• Hair follicle• Hair rootNervous structures
• Sensory nerve fiber
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Cutaneous vascular
plexusAdipose tissue
Structure of the Skin
• Epidermis
• 4-5 main layers
• Stratum corneum
• Surface layer, dead cells
• Keratin
• Stratum germinativum
• Dividing cells
• Melanin
Copyright © 2010 Pearson Education, Inc. Figure 5.1
Epidermis
Hair shaft
DermisReticular
layer
Papillary
layer
Hypodermis
(superficial fascia)
Dermal papillae
Pore
Subpapillary
vascular plexus
Appendages
of skin
• Eccrine sweat
gland• Arrector pili
muscle• Sebaceous
(oil) gland• Hair follicle• Hair rootNervous structures
• Sensory nerve fiber
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Cutaneous vascular
plexusAdipose tissue
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Structure of the Skin
• Dermis
• Deep to epidermis
• Contains
• Connective tissue
• Nerve endings
• Blood vessels
• Hair follicles
• Skin glands
• Hypodermis
Copyright © 2010 Pearson Education, Inc. Figure 5.1
Epidermis
Hair shaft
DermisReticular
layer
Papillary
layer
Hypodermis
(superficial fascia)
Dermal papillae
Pore
Subpapillary
vascular plexus
Appendages
of skin
• Eccrine sweat
gland• Arrector pili
muscle• Sebaceous
(oil) gland• Hair follicle• Hair rootNervous structures
• Sensory nerve fiber
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Cutaneous vascular
plexusAdipose tissue
Structure of the Skin
• Epidermis and dermis are attached to each other with varying
degrees of strength
Structure of the Skin
• Epidermal derivatives
• Hair
• Structure
• Root
• Shaft
• Follicle
• Pigments
• Melanin = ranges of colors = yellow/red, brown, black
• Gray = lack of pigment
• Carotene = yellowish
Copyright © 2010 Pearson Education, Inc. Figure 5.1
Epidermis
Hair shaft
DermisReticular
layer
Papillary
layer
Hypodermis
(superficial fascia)
Dermal papillae
Pore
Subpapillary
vascular plexus
Appendages
of skin
• Eccrine sweat
gland• Arrector pili
muscle• Sebaceous
(oil) gland• Hair follicle• Hair rootNervous structures
• Sensory nerve fiber
• Pacinian corpuscle
• Hair follicle receptor
(root hair plexus)
Cutaneous vascular
plexusAdipose tissue
Structure of the Skin
• Epidermal derivatives
• Hair cont.
• Functions
• Insulation
• Protection
• Sensation
• Psychosocial
• Nails
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Structure of the Skin
• Epidermal derivatives
• Glands
• Sebaceous
• Associated with hair follicles
• Secrete oil
• Fats, cholesterol, proteins, salts
• Functions
Structure of the Skin
• Epidermal derivatives
• Glands
• Sudoriferous
• Tubular glands, numerous on palms and soles
• Secrete sweat
• Water, salts, urea, uric acid, amino acids, lactic
acid, ascorbic acid
• Functions
Structure of the Skin
• Epidermal derivatives
• Glands
• Ceruminous
• Secrete ear wax
• Modified sweat glands
• Functions
Functions of the Skin
• Sensation
• Protection
• Chemical, physical/mechanical, biological
• Excretion
• Vitamin D production
• Temperature regulation
Copyright © 2010 Pearson Education, Inc. Figure 1.5
Sweat glands activated
Shivering
begins
StimulusBody temperature
risesBALANCE
Information sent
along the afferent
pathway to control
center
Information sent
along the afferent
pathway to control
center
Afferent
pathway
Afferent
pathway
Efferent
pathway
Efferent
pathway
Information sent
along the efferent
pathway to
effectors
Information sent
along the efferent
pathway to effectors
StimulusBody temperature falls
Receptors
Temperature-sensitive
cells in skin and brain
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Sweat glands
Effectors
Skeletal muscles
Control Center
(thermoregulatory
center in brain)
Control Center
(thermoregulatory
center in brain)
Response
Evaporation of sweat
Body temperature falls;
stimulus ends
Response
Body temperature rises;
stimulus ends
Skin Disorders
• Color can be an important indicator of health
• Pigmentation
• Paleness/redness
• Cyanosis
• Jaundice
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Skin Diseases
• Acne
• Impetigo
• Psoriasis
• Decubitus ulcers
• Sunburn
• Skin cancer
• Basal cell carcinoma
• Squamous cell carcinoma
• Melanoma
• Systemic lupus erythematosis
• Warts
Acne
• Hair follicles plug with oil and dead skin cells
• May become infected and inflammed
• Influenced by a number of factors (hormones, stress, etc)
Impetigo
• Highly contagious skin infection
• Caused by Staphylococcus aureus
• Common in young children
• Blisters or sores usually appear on face, neck, hands, and
diaper area
Psoriasis
• Buildup of skin cells due to overdivision
• Dry, scaly, itchy patches
• Thought to be an immune system problem
• Genetic, but attacks are triggered by infection, stress, and cold
Decubitus ulcers (bedsores)
• Skin injury resulting from prolonged pressure
• Pressure on one side + bone on the other = lack of blood flow
• Develop quickly, hard to treat, slow to heal (easier to prevent)
• Common in those with limited mobility
Sunburn
• Damage to skin from overexposure to UV light
• Peeling = body’s attempt to shed damaged cells
• Damage to blood vessels underneath = increased blood flow
and warmth
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Cancer
Basal cell carcinoma
Malignant melanoma
• Uncontrolled cell growth due to genetic changes
• Cells may metastasize and spread to other areas of the body
Burns
• Causes
• Heat
• Chemicals
• Electricity
• Radiation
• Dangers
• Fluid and plasma protein loss → shock
• Infection
• Circulation
• Kidney damage
• Scarring
Burns
• Classification
• Rule of nines
• Treatment
Surface area percentage reference
This illustrates the difference between infants and adults
Burns
• First degree
• Epidermal damage only
• Localized redness and pain
• Second degree
• Epidermal and upper
dermal damage
• Blistering, edema and pain
Copyright © 2010 Pearson Education, Inc. Figure 5.10a
(a) Skin bearing partial
thickness burn (1st and
2nd degree burns)
1st degree
burn
2nd degree
burn
Burns
• Third degree
• Entire thickness of skin damaged
• Gray-white, cherry red, or black
• No initial edema or pain (nerve endings destroyed)
• Skin grafting usually necessary
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Burns
• Critical if:
• >25% of the body has second-degree burns or worse
• >10% of the body has third-degree burns
• Face, hands, or feet have third-degree burns
Copyright © 2010 Pearson Education, Inc. Figure 5.9
Anterior and posteriorhead and neck, 9%
41/2%41/2%
Anterior and posteriorupper limbs, 18%
Anterior and posteriorlower limbs, 36%
100%
Totals
Anterior and posteriortrunk, 36%
Anterior
trunk,
18%
9% 9%(Perineum, 1%)
41/2%
Burns
• Treatment
• Cleaning and debridement
• Fluid therapy
• Protection
• Grafting
• Prevention of infection
• May require very high calorie and high protein diet
Burns
• Treatment
Skin: Developmental Aspects
• Advanced age
• Decreased blood flow to skin
• Thinning of epidermis
• Loss of subcutaneous fat
• Less collagen and elastin
• Fewer melanocytes
• Gray hair
• Reduced glandular activity