Upload
bethany-foster
View
225
Download
0
Embed Size (px)
Citation preview
INTEGUMENTARY SYSTEM
The skin (including sweat and oil glands), hair and nails
Integumentary System
Integument = coveringIncludes
Skin including sweat and oil glandsHairNails
Integumentary System Functions
1. Protection—protects underlying tissues and organs
Three types of barriers Chemical barrier—skin secretions, melanin (protects from
sun), acid mantle of skin decreases bacterial growth
(sebum kills bacteria) Physical or mechanical barrier—continuous surface of skin
(hard-fairly impermeable to disease) Biological barrier—Langerhan’s cells and phagocytes (all
work against disease)
Functions continued
2. Excretion—excrete salts, H2O, organic wastes through sweat
3. Body temperature regulation If air temp. is cold, then blood vessels in
dermis constrict which reduces heat loss through skin
If body temp. is hot, then blood vessels in dermis dilate bringing blood to skin surface where it is cooled
4. Touch reception- nerves in the dermis give us lots of info about our environment- touch, pressure pain, hot and cold
5. Vitamin D production- when skin is exposed to UV radiation it makes vitamin D
Regions
1. EpidermisSurface—many layers of epithelial
cellsFunction—protection
2. DermisUnder epidermis—thicker layermost of skin is dermisConnective tissue with blood vessels
3. Subcutaneous layer (hypodermis or superficial fascia)
Loose (fatty) connective tissueConnects skin to underlying organs
Epidermis Surface of skin Stratified squamous epithelium 4 cell types:
1. Keratinocytes—most common, make keratin(protein that makes skin strong, flexible and water resistant
Keratin is the basic component of hair, calluses and nails
When keratinocytes reach the skin surface, they’re dead cells which get worn off
Totally new epidermis every 35-45 days!
Epidermis
4 types of cells (cont.)2. Merkel’s cells- touch reception3. Melanocytes- produce the pigment
melanin4. Langerhan’s cells- part of body’s defense
against disease
Strata of the EpidermisStratum (singular) = layer 5 layers starting with the deepest
1. Stratum germinativum (stratum basale)—attached to basement membrane, cells are specialized for division. One cell layer thick.
2. Stratum spinosum (spiny layer)—several cell layers thick, spiny projections hold cells together
3. Stratum granulosum (grainy layer)—2 or 3 layers of flattened cells, keratin formation begins here
Strata of the Epidermis
4. Stratum lucidum (clear layer)—found in thick skin (palms and soles)cells flattened and densely packed
5. Stratum corneum (cornu = horn)—20-30 cell layers thick. Dead cells filled with keratin (organelles die as keratin fills cells). Lets skin surface be a protective ‘overcoat’ for the body
Dermis
Strong, flexible, connective tissue region of the skin with lots of nerve fibers, blood vessels, lymphatic vessels
Dermis
2 layers:1. Papillary—loose connective tissue
with dermal papillae that push into the epidermis. Patterns created by dermal papillae create fingerprints and line patterns on feet.
Dermis2. Reticular—dense irregular connective
tissue can tolerate stress from many directions because fibers run
in many directions.Lines of cleavage bundles of interlocking
collagen fibers that form patterns: surgical lines are often made parallel to lines of cleavage so that skin gapes less, heals more quickly, has less obvious scarring
Dermis (continued)
Flexure lines—folds in skin that allow joint movement
Stretch marks—tears in dermis caused by excessive skin stretching. Silvery scars = striae
Stratum Germinativum
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Subcutaneous layer
Sweat gland
Dermis
Adipose tissuePacinian corpuscle
Pore
Meisner’s corpuscle
Hair shaft
Dermal papillae
Sebaceous gland
Arrector pili muscle
Hair follicle
Hair root
Vein
Artery
Skin Color (3 Pigments)
1. Melanin—yellow to orange to brown made by melanocytes and transferred into
keratinocytes (keratin cells) Skin color varies by the amount and kind of
melanin made NOT by number of melanocytes(everyone has the same number of melanocytes)
Black and brown skinned people make more and darker melanin than lighter skinned people
Freckles and dark moles show local accumulations of melanin
Skin Color (3 Pigments)
Sun exposure leads to a build up of melanin providing some protection from the sun
Excessive sun exposure damages skin (elastic fibers clump leading to leathery, wrinkled skin and damage to the immune system) and can change DNA in cells leading to skin cancer
Melanin is a natural sunscreen Some antibiotics and antihistamines increase the
skin’s sensitivity to the sun-> rashes, blisters and skin peeling
Skin Color (3 Pigments) continued
2. Carotene—yellow/orange pigment Found in stratum corneum and subcutaneous
adipose tissue Shows most in palms and soles Found in fruits and vegetables Asian skin color is the result of a combination of
carotene and melanin
Carotene and keratin sound alike- what’s the difference?
3. Hemoglobin—red pigment from well oxygenated blood
Shows in pinkish color of caucasians (transparent epidermis) so hemoglobin from the capillaries in the dermis shows through
Too little oxygen causes skin to look blue (cyanosis). Can be seen in mucous membranes and nail beds of dark skinned people.
This can be caused by heart failure and severe respiratory disorders.
Skin Color Changes
Changes can be caused by emotional states and/or disease
Erythema—redness (embarrassment, fever) Pallor—paleness (fear, anemia) Jaundice—yellowing (liver disease) Bronzing—metallic appearance (Addison’s
disease) Bruises—blood escapes from vessels and
clots in tissues (hematoma). May be result of too little vitamin C or a bleeding disorder.
Hair Structure
Shape of shaft determines whether hair is curly or straight
Flat shaft=curlyOval shaft=wavyRound shaft= straight
3 layers of hair
Medulla
Cortex
Cuticle
Accessory Structures
Hair and hair folliclesFunctions of hair:
Protects head-from sun, heat
loss, and physical traumaShields eyes (lashes)Helps keep dust and
particles out of respiratory tract (nose hairs)
Hair Structure
Produced and contained in hair follicleMade of keratinShaft—part of hair above skin surfaceRoot—part of hair beneath skin surface
Hair Color
Melanocytes at base of hair send melanin into cells of cortex—combinations of yellow, brown & black melanin produce all hair colors
White or gray hair caused by decreased melanin production causing air bubbles to replace melanin in the hair shaft.
Cuticle
Cortex
Medulla
Melanocyte
Bulb
Hair Growth
Growing part of hair is at the root (in the bulb)Hair follicles begin deep in the dermis,
sometimes even in the subcutaneous layerOther structures connected with hair:
Nerve endings around bulbSebaceous (oil) glands lubricate hairArrector pili muscles--smooth muscle in dermis
Pull on hair follicle to make it stand up—goose bumps
Activated by cold, fright, or other strong emotion
Hair Growth (continued)
100,000 hairs in scalp, 30,000 in beardWhere on your body do you have no
hairs?3 types
Vellus—fine body hair of women and kidsTerminal—coarser, longer hair of scalp,
eyebrows, pubic and axillary areas as well as face and chest of men
Intermediate—all hair that doesn’t fit into other categories
Hair Growth (continued)
Nutrition and hormones affect hair growthPoor nutrition (esp. low
protein) Increased blood flow Testosterone Other factors that reduce hair growth:
high fever, surgery, emotional trauma, drugs
Hirsutism
Hair Growth
Hirsutism- excessive hair growth especially male pattern hair growth in women (often caused by adrenal gland tumor)
Hair Growth (continued)
Growth averages 1.5-2.2 mm per week Growth is fastest from teens – age 40 Hair thins with age because hairs are not
replaced as fast as they’re lost Growth cycle—active phase followed by
resting (inactive or dormant) phase Scalp follicles active for years, then inactive for
a few months (shed 50-90 a day) Eyebrow follicles active for 3-4 months Alopecia = baldness
Hair Growth
Alopecia=baldnessUsually starts at anterior hairline and
progresses posteriorlyTerminal hairs are replaced by vellus hairsMale patterned baldness- hereditary, sex-
linked. Growth cycles become super shortMedicine or hair transplant
Accessory StructuresNailsSimilar in structure to
hoof or claw in animalsHave free edge (visible) and root
(beneath skin)Pink because of blood supply in dermisStructure:
Lunula—white crescent at baseCuticle—thickened fold of skin at baseNail bed—stratum germinativum under
entire nail
Accessory StructuresSudoriferous Glands Sudoriferous Glands = Sweat Glands (2 types) 3 million over body EXCEPT: lips, nipples and
parts of external genitalia 1. Eccrine (merocrine) sweat glands
Most abundant type especially on palms, soles and forehead
Ducts go to pores on skin surface Secretion = sweat—99% water with salts and
wastes. Function: maintain body temp.
Sudoriferous Glands (continued)
2. Apocrine sweat glands Found mostly in axillae and genital-rectal areas Ducts end in hair follicles Apocrine sweat has same elements as eccrine
sweat plus fatty acids and proteins. Bacterial action on fatty acids and proteins is what
creates odor Begin to function at puberty.
Ceruminous glands—specialized apocrine glands that produce cerumin (ear wax)in the ear canal
Accessory StructuresSebaceous Glands
Sebaceous Glands = Oil Glands Found all over body except palms and soles Larger on face, neck and upper chest Sebum = oily secretion—usually travels
through duct to hair follicle, sometimes to pore on skin surface
Functions—sebumSoftens and lubricates hair and skinPrevents water loss from skinKills bacteria
Sebaceous Glands (continued)
Sex hormones cause sebaceous glands to become active at puberty
Clinical terms:Whitehead—blocked sebaceous glandBlackhead—sebum dries and darkensAcne—inflammation of sebaceous gland
usually due to bacterial infectionSeborrhea—over activity of sebaceous
glands. Causes oily scales that come off.
Skin Disorders
Albinism—(albino) melanocytes can’t make melanin Absence of pigmentation in skin, hair, eyes.
Athlete’s foot—fungus infection leads to itchy, red, peeling skin between toes
Boils—inflammation of hair follicles and sebaceous glands (cause: bacterial infection)
Cold sores—herpes virus infection. Causes blisters filled with fluid around lips and mouth
Contact dermatitis—caused by exposure to chemicals that create allergic response
Albino & Athletes Foot
Boils & Cold Sores
Contact Dermatitis & Decubitus Ulcer
Skin Disorders (continued) Decubitus ulcers—bed sores/pressure sores Impetigo—contagious rash Mongolian spots—bruised looking area at sacrum
—birth mark Psoriasis—chronic, hereditary condition.
Reddened spot covered with scales. Vitiligo—loss of pigment in patches of skin Genital Warts—caused by
HPV
Burns
Tissue damage caused by heat, electricity, chemicals, radiation
Burns are a major cause of death for those <40
Burns
Immediate threat to life—fluid lossFluids contain proteins and electrolytes,
fluid loss->dehydration and electrolyte imbalance->kidney failure and decreased blood circulation
Lost Fluids need to be replaced immediatelyNutrient needs are very high in burn
patients.
Burns
After immediate crisis—infection is biggest threat to lifeBarrier destroyed Immune system function decreases
Burns Only epidermis is
damaged—redness, swelling, pain. Heal in
2-3 days Epidermis and upper part
of dermis—1st degree S&S plus blisters. Skin regeneration. Heal 3-4 weeks if no infection.
Full thickness—burned areas look gray-white or black. Nerve endings destroyed(no pain). Skin grafting needed
Rule of Nines
Method for estimating how much of skin surface is burned.
Body is divided into areas that amount to 9% of skin surface.
Critical Burns
3 classes of critical burns30% of body has 2nd degree burnsMore than 10% has 3rd degree burnsAny 3rd degree burn on face, hands or
feet
Skin Cancer
3 types:1. Basal Cell Carcinoma
Starts in stratum germinativumMost common, least malignantFull cure with surgical removal in 99%Found on surfaces exposed to the sunStart as shiny, raised area and develop into
central ulcer surrounded by “pearly” edge
Skin Cancer Types (continued)
2. Squamous cell carcinomaStarts in stratum spinosumScaly reddened bump—grows rapidlySun exposureMetastasis rare
Skin Cancer Types (continued)
3. Malignant MelanomaCancer of melanocytesRarer than other types, but deadlyMelanomas often have irregular borders,
multiple colors, rapid growth, and bleed easily.
ABCD Rule for Melanoma Be on the look out and notify your doctor about any of the
following changes to a mole or birthmark:
A is for ASYMMETRY: One half of a mole or birthmark does not match the other.
B is for BORDER: The edges are irregular, ragged, notched, or blurred.
C is for COLOR: The color is not the same all over, but may have different shades of brown or black, sometimes with patches of red, white, or blue.
D is for DIAMETER: The area is larger than 6 millimeters (about ¼ inch -- the size of a pencil eraser) or is growing larger.
The most important warning sign for skin cancer is a spot on the skin that changes in size, shape, or color.
Development
Embryonic developmentBy 4th month—skin well formed5th and 6th month—lanugo7th month vellus hairs appearAt birth—vernix caseosa (produced by
sebaceous glandsNewborn skin thin and often covered by
milia (sebaceous secretion) on nose and cheeks—goes away by 3-4 weeks after birth
Development (continued)
AdolescenceSkin and hair oilerAcne usually goes away in early adulthoodSkin usually looks its best in 20s and 30s
DevelopmentOld Age
Changes caused by continued exposure over time Epidermal cells have slower mitosis—skin thins Sebaceous and sweat glands less active—skin gets drier
and itchy Collagen and elastic fibers fewer and stiffer Subcutaneous fat layer decreases leading to decreased
tolerance to cold Melanocytes less active—decreased protection from sun Light skinned, light haired people tend to show signs of
age sooner To reduce aging changes—decrease sun exposure, eat
well, get lots of fluids
Integumentary System Effect on other Systems
Entire skin is only as thick as a paper towel! When the skin is damaged almost every body
system reacts Each system gets something from the
integumentary system and gives something to the integumentary system.
What examples can you think of?