Download Integumentary System and Body Membranes

Integumentary System and Body
Membranes
Structure and Function
Love the Skin You’re In!
 Skin..Cutaneous
Membrane
– Largest, most visible, primary
organ
– Composes 16% of body weight
– Superficial layer is epithelial,
underlying layer is connective
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Structure of the Skin: Layers
EPIDERMIS
 DERMIS
 SUBCUTANEOUS TISSUE
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Structure of the Skin:
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Epidermis..outermost layer of the skin constantly
replaced from underneath layer.
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Dermis..deeper,thicker layer, composed of connective
tissue
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Basis of fingerprints
Contain nerve endings, muscle fibers, hair follicles, sweat &
sebaceous glands, & blood vessels
Structure of the Skin:
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Subcutaneous tissue..thicker layer of loose
connective tissue & fat
– Insulates from heat & cold
– Shock absorbing pad to protect
– Stored source of food & energy
Structure of the Skin:
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Keratin..hard protein substance in nails, hair,
skin,
Pigment ..produced by deepest layer of
epidermis, gives color to the skin,
Melanin..Brown pigment produced by
melanocytes in the epidermis
FYI: Millions of epithelial cells reproduced &
shed daily
SKIN STRUCTURE:
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FUNCTION OF SKIN:
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Protection..first line of defense against
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Temperature regulation
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infection by microbes
ultraviolet rays from sun
harmful chemicals
cuts & tears
Regulation of sweat secretion
Regulation of blood flow close to the body surface
Sensory organ detects all changes in
environment
Appendages of the skin:
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Appendage..something that is attached
Hair
Receptors
Nails
Skin glands
– Sweat
– Sebaceous
Appendages of the Skin:
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Body Hair
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Lanugo, extremely fine soft hair on newborn
infants
Follicles.. small tubes where hair growth
occurs
Hair root hidden in the follicle,visible hair
called shaft
Only hairless areas are lips, palms, and
soles
HAIR:
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Appendages of the Skin:
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Receptors
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Make it possible for body surface to sense
touch,pain,temperature, & pressure
Meissner’s corpuscle ..close to the skin surface
make light touch sensation possible
Pacinian corpuscle.. deep in the dermis, detect
pressure on the skin surface
Free nerve endings ..respond to pain &
temperature changes
Krause’s end bulbs.. detect touch sensation & low
freq. vibrations
Appendages of the Skin:
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Nails
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Nail body..visible part of the nail
Root..lies in a groove , hidden by a fold of skin
Cuticle..fold of skin which holds the nail body in
place
Lunula..crescent-shaped white area nearest the
root
Nail bed.. Under the nail, a layer of epithelium
containing abundant blood vessels
NAILS:
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Appendages of the Skin:
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Sudoriferous or Sweat Glands
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Sebaceous or Oil glands
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Eccrine.. produce perspiration, (most numerous &
wide spread)
Apocrine sweat glands .. secretes thick, milky
secretions which breakdown & cause odor (found in
axilla & around genitalia)
Secrete oil or sebum for hair & skin
Secretion increases during adolescence
Sebum may darken in gland ducts to form
blackheads
SWEAT GLAND:
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What is a Membrane?
 Simple
thin, sheetlike cell structures
Cover & protect body surface
– Lines body cavities
– Cover inner surfaces of hollow organs
– Secrete lubricating fluids
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Two Types of Membranes:
 Epithelial
membranes
Cutaneous
– Serous
– Mucous
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 Connective
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Synovial
tissue membranes
Serous Membrane:
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Found on the surface of closed cavities
Composed of two distinct layers
– Parietal portion,lines the walls of body
cavities
– Visceral portion,covers organs found in
body cavities
Squamous epithelium & connective tissue
called basement membrane
REVIEW BODY CAVITIES:
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Examples of Serous Membranes:
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Pleura: membrane of the thoracic cavity
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Peritoneum: membrane in the abdominal
cavity
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Pleurisy : very painful inflammation of the pleura
that line the chest cavity & cover the lungs
Peritonitis : inflammation of the abdominal cavity
membranes, can be secondary to infected or
ruptured appendix
Mucous Membranes are:
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Epithelial membranes that line body surfaces
opening directly to the exterior of the body.
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The mucocutaneous junction is where the
skin & the mucous membranes meet.
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Examples: eyelids, nasal openings, vulva ,and anus
have mucocutaneous junctions
Connective Tissue Membranes:
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Synovial membranes line the spaces
between bones and joints
Secrete a thick, colorless lubricating fluid,
synovial fluid, to reduce friction
Also line the bursae, small cushionlike sacs
found between moving body parts.
FYI: Do not contain epithelial tissue
The Skin in Perspective:
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Architectural Marvel
In one (1) inch of skin there are:
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500 sweat glands
Over 1000 nerve endings
Nearly 100 sebaceous glands
150 sensors for pressure
75 sensors for heat
10 sensors for cold
Millions of cells
FUN FACTS:
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Humans shed and regrow outer skin cells
about every 27 days.
Every square inch of skin has about 9.5
million skins cells
By age 70, the average person will have lost
105 pounds of skin.
Disorders of the Skin
Skin Lesions
Burns
Skin Infections
Skin Cancer
Disorders of the Skin
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Dermatosis..any disorder of the skin, skin
condition
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Dermatitis..
involves inflammation
of the skin
Skin Lesions
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Lesion..any measurable variation from the
normal structure of a tissue
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Not necessarily signs of disease,Freckles are
lesions, but benign
May be elevated, flat,or depressed
Abnormal coloration, density,
calcification
Herpes Zoster lesion
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Burns
Skin Damage or destruction caused
by:
 Fire or contact with hot surfaces
 Overexposure to ultraviolet light
(sunburn)
 Contact with electric current
 Harmful chemicals (acids)
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Surface Area of Burns:
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The Rule of “9’s”
Burns:
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sunburn
Third degree
Classification of Burns:
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First-degree
– Minimal tissue destruction
– No blistering
– Minor discomfort
Second-degree
– Involves the deep epidermal layers
– Damages sweat glands, hair follicles, sebaceous
glands
– Blisters, severe pain, generalized swelling, fluid loss
– Scarring is common, injures/destroys epidermal
layers
Classification of Burns:
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Third Degree
– Full thickness burn
– Complete destruction of epidermis & dermis
– May extend into subcutaneous, muscle, and
bone
– Serious fluid loss problem
– Insensitive to pain immediately due to
destruction of nerve endings
Depth of Burns by degrees:
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Skin Infections Facts:
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The skin is the first defense against
Infection
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Skin is commonly a site of infection
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Conditions may be caused by viruses,
bacteria, fungi or larger parasites.
Skin Infections:
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Impetigo..staph or strep infection in young
children,starts with erythema, vesicles, then yellowish
crusts
Tinea..fungal skin infections includes ringworm,
jock itch, and athlete’s foot. Signs include
erythema,scaling and crusting, with itching.
Warts.. papilloma virus,benign neoplasm, contagious
by direct contact. Removed by freezing, drying, laser
therapy, chemical applications
Skin Infections:
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Ringworm
warts
Skin Infections:
Boils/Furuncles..staph infections of hair
follicles. Large inflamed pustules.
 Carbuncles.. group of untreated boils that fuse
into larger pus-filled lesion.
 Scabies.. Contagious condition
caused by itch mites. Young
mites hatch causing rash,
erythema
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Vascular/Inflammatory Skin
Disorders:
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Decubitus..pressure sores caused by lying in
one position for long periods. Common sites
include heels, and over bony prominences.
Urticaria..hives/itching,red raised lesions
called wheals, caused by hypersensitivity or
allergic reaction.
Scleroderma..autoimmune disease,mild
localized inflammed patches which later turns
yellowish, hardened skin.
Decubitus Ulcer:
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Vascular/
Inflammatory Skin
Disorders:
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Psoriasis..common,
chronic inflammatory disorder of cutaneous
tissue characterized by scaly plaques of
epithelial tissue.
Eczema..most common inflammatory disorder,
characterized by papules, vesicles, and crusts.
It is a symptom of underlying condition.
Example: Poison ivy causes contact dermatitis
and eczema
Skin Cancer
Squamous cell carcinoma
 Basal cell carcinoma
 Melanoma
 Kaposi’s sarcoma
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Skin Cancer:
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Squamous cell carcinoma
– Malignant tumor of the epidermis
– Most common type of skin cancer
– Slow growing
– Hard, raised nodules, usually painless
– Will metastasize and invade other organs
Skin Cancer:
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Basal cell carcinoma
– Occurs on upper face
– Malignant, begins in base of
the epidermis
– Begin as papule
– Form bleeding, crusted
crater
– Less likely to metastasize
than other types
Skin Cancer:
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Melanoma
– Malignant,fastest growing,
serious cancer
– Causes death in 1in 4
cases
– May develop from
pigmented nevus (moles)
– Use the “ABCD” rule to self
exam for melanoma
Skin Cancer:
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Kaposi’s Sarcoma
– Rarer skin cancer
– Appears in AIDS and
other immune deficiencies
– Appears as purple
papules
– Spreads quickly to lymph
nodes and internal organs
Skin Cancers:
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USING THE “ABCD” RULE