Download The Integtumentary System

The
Integtumentary
System
Functions of the Integument
• Protection
• Excretion
• Sensory
• Water balance
• Thermoregulation
• Endocrine (Vitamin D)
Some facts about skin
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Largest organ of the Body
Approximately 2 square meters or 22 square feet
About 5 kg (11 pounds)
Ranges in thickness between 0.5 mm (genitals, lips,
eyelids) to 5 or 6 mm on the soles of the feet.
• Three layers, from superficial to deep:
1. Epidermis - outer layer of dead, keratinized cells
2. Dermis - dense irreg. c.t., nerves, vessels, etc.
3. Hypodermis - mostly subcutaneous adipose tissue
Slice o’ skin
Skin: Thick
Stratum granulosum
Stratum corneum
Stratum spinosum
Stratum Basale
Dermis
Thin skin: scalp
Human scalp
Scalp: deep
Human scalp
The
Epidermis
Skin Glands
There are two general types of skin glands:
1. Sudoriferous glands (sweat glands).
• Eccrine glands - produce watery sweat for
cooling, waste metabolite excretion & electrolyte
excretion. Found all over the body except nail
beds, genitals, & ear drums. Most dense on
palms, soles, forehead & chest.
• Apocrine glands - produce “stinky” sweat.
Secrete a thicker, protein and lipid rich fluid and
“pheromones”. Concentrated in arm pits, pubic
region, areolae. Activated by the stress
response or sexual arousal (sympathetic n.s.)
Skin Glands b.
• Mammary glands - Mammary glands are
specialized sudoriferous glands. They produce
milk. And yes, men have them too!
• Ceruminous glands - Modified sweat glands that
line the external auditory canal. They make
“cerumen”, also known as ear wax.
2. Sebaceous glands - produce oily secretion called
“sebum”. These glands open onto the hair follicles
and the oil keeps hair supple and skin water
resistant..
The Dermis: Glands
Epidermal Appendages: Hair
Connective tissue
Root sheath
Follicle wall
Hair follicle: cross section
Internal root sheath
Cuticle
Cortex
Medulla
Hair follicle in cross section
The
Follicle
Epidermal Appendages: Nails
Wound
healing
PMN =
Polymorphonuclear
leukocyte
Stages of wound healing
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Inflammatory
Migratory
Granulation
Maturation
– Fibrosis: scar tissue formation
• Hypertrophic scar is one that remains within the
boundaries of the original wound.
• Keloid scar is one that extends to surrounding
tissue beyond the original wound.
The Rule
of Nines
Burns
First degree (partial thickness)
Second Degree
First & second degree burns
Third degree (full thickness)
Third degree burns
Skin Cancer
• Basal cell carcinoma - 75%, arise from epidermal cells.
Rarely metastasize to other tissues. Easily removed.
• Squamous cell carcinoma - around 20%, may or may not
metastasize. Also from epidermal tissue.
• Malignant melanoma - remaining 5%, arise from
melanocytes. Often delayed reaction to sun exposure by 10 20 years. Poor prognosis, they metastasize very rapidly
once they begin to grow.
ABCDs of
skin cancer
detection
Risk factors for skin cancer
• Skin type - lighter skin pigmentation =
higher risk
• Sun exposure - lower latitude, more direct
sun. Longer time, greater exposure.
• Family history - Genetics nearly always
plays at least some role in susceptibility to
disease.
• Age - older = longer exposure.
• Immune system health - people with
compromised immune systems are at
greater risk.
Fungating Melanoma
Other skin pathologies
• Athlete’s foot - caused by a fungus
• Cold sore - herpes simplex virus type I. HSV II causes
genital herpes.
• Acne - inflamed sebaceous glands. Can be seriously
disfiguring. Accutane™ and Retin-A™ are prescription
treatments which are derived from vitamin A and have proven
helpful in severe cases. OTC treatments include salicylic acid
and benzoyl peroxide with variable efficacy.
• Impetigo - superficial infection caused by staphylcocci or
streptococci, two genera of bacteria very common to skin.
• Warts - raised lesions caused by papilloma virus. HPV
causes genital warts, a sexually transmitted infection, that is
often associated with cervical cancer in women.
Another
great use
for skin