integumentary system. key terms dermis dermis epidermis epidermis hair hair hair follicle hair...
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Integumentary Integumentary SystemSystem
Key TermsKey Terms
DermisDermis EpidermisEpidermis HairHair Hair follicleHair follicle IntegumentIntegument keratinkeratin
MelaninMelanin NailNail Sebaceous glandSebaceous gland StratumStratum Subcutaneous Subcutaneous
layerlayer Sweat glandSweat gland
Structure of skin:Structure of skin:
Largest organ in the bodyLargest organ in the body 16% of our weight16% of our weight
Overview of skinOverview of skin Components of skinComponents of skin
The Skin Is Made Up of 2 The Skin Is Made Up of 2 LayersLayers
EpidermisEpidermis outer layer; outer layer;
its made up its made up of 4 types of of 4 types of cells in 4-5 cells in 4-5 layers layers
4 Types of Epidermal Cells4 Types of Epidermal Cells
a) a) keratinocytes keratinocytes - make up the - make up the outer, protective layer of skin cells outer, protective layer of skin cells
b) b) melanocytes melanocytes - produce melanin to - produce melanin to color the skin and protect it from UV color the skin and protect it from UV rays rays
c) c) Merkel cellsMerkel cells - associated with - associated with sensory receptors sensory receptors
d) d) Langerhans cellsLangerhans cells - macrophages - macrophages that help fight off infections that help fight off infections
Layers of the SkinLayers of the Skin
There are usually There are usually four four layers of skin. layers of skin. However, the soles of the feet and However, the soles of the feet and palms of the hand have five layers. palms of the hand have five layers. The extra fifth layer is the stratum The extra fifth layer is the stratum lucidum (clear layer) lucidum (clear layer)
a) a) Stratum basaleStratum basale (basal layer) - the (basal layer) - the deepest layer; mostly a single layer of deepest layer; mostly a single layer of keratinocytes that produce new skin keratinocytes that produce new skin
b) b) Stratum spinosumStratum spinosum (spiny layer) (spiny layer) c) c) Stratum granulosumStratum granulosum (granular layer) (granular layer) d) d) Stratum lucidum Stratum lucidum (clear layer) - the (clear layer) - the
extra layer on palms & soles extra layer on palms & soles e) e) Stratum corneumStratum corneum (horny layer) - the (horny layer) - the
outer layer of keratinized dead cells; it's outer layer of keratinized dead cells; it's 20-30 cell layers thick; waterproof 20-30 cell layers thick; waterproof
Dermis…Inner LayerDermis…Inner Layer
1) made of strong, 1) made of strong, flexible connective flexible connective tissue tissue
2) full of nerves, 2) full of nerves, blood vessels, hair blood vessels, hair follicles, oil & sweat follicles, oil & sweat glands glands
3) It's composed of 3) It's composed of two layers. two layers.
a) a) papillary papillary - thin; superficial; full of blood - thin; superficial; full of blood vessels; the papillary layer pushes up to form vessels; the papillary layer pushes up to form dermal ridges; these ridges (which produce dermal ridges; these ridges (which produce epidermal ridges above) create the fingerprint epidermal ridges above) create the fingerprint pattern; sweat glands at the top edge of the pattern; sweat glands at the top edge of the ridges produce an oil pattern which we call ridges produce an oil pattern which we call fingerprints fingerprints
b) b) reticular reticular - deeper layer which comprises - deeper layer which comprises 80% of the dermis; dense irregular connective 80% of the dermis; dense irregular connective tissue; contains thick bundles of interlacing tissue; contains thick bundles of interlacing collagen fiberscollagen fibers
HypodermisHypodermis
Lowermost layer, mostly adipose and Lowermost layer, mostly adipose and aerolar connective tissue, attaches aerolar connective tissue, attaches down to muscle layer beneathdown to muscle layer beneath
Skin ColorSkin Color
There are There are three three pigments that make pigments that make up skin color up skin color
MelaninMelanin
a) made in the skin a) made in the skin b) protects the body from UV radiation; b) protects the body from UV radiation;
the more melanin ... the more protection the more melanin ... the more protection c) more melanin = darker skin; less c) more melanin = darker skin; less
melanin = lighter skin melanin = lighter skin d) freckles and moles are small areas of d) freckles and moles are small areas of
concentrated melanin concentrated melanin e) melanin production increases with e) melanin production increases with
exposure to the sun; more melanin is exposure to the sun; more melanin is made (and the skin darkens) to better made (and the skin darkens) to better protect the skin protect the skin
carotenecarotene
a) yellow/orange pigment a) yellow/orange pigment b) found in carrots and certain other b) found in carrots and certain other
plants plants c) accumulates in the stratum c) accumulates in the stratum
corneum; so the color becomes most corneum; so the color becomes most evident in areas of thick stratum evident in areas of thick stratum corneum (palms & soles) corneum (palms & soles)
HemoglobinHemoglobin
blood under the skin gives it a blood under the skin gives it a pinkish hue, especially in light-pinkish hue, especially in light-colored people colored people
Skin AppendagesSkin Appendages
HairHair
a) composed of the shaft (long part) a) composed of the shaft (long part) and the root (in the follicle) and the root (in the follicle)
b) made of b) made of 33 layers of keratin layers of keratin c) hair color is created by different c) hair color is created by different
levels of melanocytes (yellow, rust, levels of melanocytes (yellow, rust, brown, black) in the follicle brown, black) in the follicle
Hair FollicleHair Follicle
a) contains the root of the hair at the a) contains the root of the hair at the hair bulb (enlarge area at the base) hair bulb (enlarge area at the base)
b) a knot of sensory nerve endings b) a knot of sensory nerve endings (root hair plexus) is wrapped around (root hair plexus) is wrapped around the hair bulb the hair bulb
c) attached to an arrector pili muscle, c) attached to an arrector pili muscle, which erects the hair (goosebump) which erects the hair (goosebump)
Distribution, types and growth Distribution, types and growth of hair of hair
Distribution of hair Distribution of hair i) found all over, except for lips, i) found all over, except for lips,
nipple, palms, soles, external nipple, palms, soles, external genitalia genitalia
ii) there are about 100,000 in the ii) there are about 100,000 in the scalp scalp
Two types of hairTwo types of hair
i) i) vellus vellus - fine body hair; baby hair - fine body hair; baby hair ii) ii) terminal hair terminal hair - thicker, darker, - thicker, darker,
courser hair on the scalp, eyebrows, courser hair on the scalp, eyebrows, beard, axillary & pubic regions beard, axillary & pubic regions
Rate of hair growth - 2 mm per week Rate of hair growth - 2 mm per week (that's about an inch every 3 (that's about an inch every 3 months) months)
Hair Thinning and BaldnessHair Thinning and Baldness
) ) Alopecia Alopecia - loss of hair that is not - loss of hair that is not replaced; baldness; occurs in men & replaced; baldness; occurs in men & women women
b) b) Male pattern baldnessMale pattern baldness - occurs - occurs in men only; caused by genetics in men only; caused by genetics
NailsNails
hardened keratin at the tips of the hardened keratin at the tips of the fingers & toes fingers & toes
1) 1) Cuticle Cuticle - edge where nail meets - edge where nail meets skin skin
2) 2) Lunula Lunula - thickened half-moon - thickened half-moon shaped area above the nail matrix; shaped area above the nail matrix; distal to the cuticle distal to the cuticle
SweatSweat
Occur everywhere Occur everywhere (except for the (except for the nipples and nipples and external external genitalia); 2.5 genitalia); 2.5 million per person million per person
2) There are 2) There are 22 types types
eccrineeccrine
i) most common; especially on the i) most common; especially on the palms, soles, and forehead palms, soles, and forehead
ii) they secrete sweat, which is ii) they secrete sweat, which is composed of: 99% water, salts, composed of: 99% water, salts, antibodies, metabolic wastes, lactic antibodies, metabolic wastes, lactic acid, and vitamin C acid, and vitamin C
apocrineapocrine
i) mostly in the axillary (underarm) and apogenital i) mostly in the axillary (underarm) and apogenital areas areas
ii) larger than eccrine glands ii) larger than eccrine glands iii) empty directly into hair follicles iii) empty directly into hair follicles iv) though odorless when produced, bacteria quickly iv) though odorless when produced, bacteria quickly
act as it reaches the surface and create a musky odor act as it reaches the surface and create a musky odor v) the name is incorrect; they are actually merocrine v) the name is incorrect; they are actually merocrine
glands glands vi) vi) ceruminous glandsceruminous glands are a type of apocrine gland; are a type of apocrine gland;
located in the ear canal, they produce cerumen located in the ear canal, they produce cerumen (earwax) (earwax)
vii) vii) mammary glandsmammary glands are another specialized type are another specialized type that produce milk (in women) that produce milk (in women)
Oil GlandsOil Glands
1) Occur everywhere (except for the 1) Occur everywhere (except for the palms and soles) palms and soles)
2) Produce sebum to soften & 2) Produce sebum to soften & lubricate the hair and skin; it also lubricate the hair and skin; it also helps to waterproof the skin helps to waterproof the skin
Interactives:Interactives:
Skin conditionsSkin conditions Sun’s effectsSun’s effects SweatingSweating Skin infectionsSkin infections
Functions of the SkinFunctions of the Skin
ProtectionProtection
1) 1) Physical (mechanical) barrierPhysical (mechanical) barrier - - between internal tissues and the between internal tissues and the environment environment
2) 2) Biological barrierBiological barrier - macrophages & - macrophages & Langerhans cells help destroy foreign matter Langerhans cells help destroy foreign matter
3) 3) Chemical barrierChemical barrier - chemicals secreted - chemicals secreted by the skin kill bacteria; melanin protects by the skin kill bacteria; melanin protects against UV radiation against UV radiation
Body Temp RegulatorBody Temp Regulator
1) As temperature rises ... 1) As temperature rises ... a) sweat is produced (evaporation of sweat a) sweat is produced (evaporation of sweat
cools you off) cools you off) b) dermal blood vessels dilate (enlarge); b) dermal blood vessels dilate (enlarge);
heat is transferred to the external heat is transferred to the external environment environment
2) As temperature falls, dermal blood 2) As temperature falls, dermal blood vessels constrict (shrink), forcing the vessels constrict (shrink), forcing the blood to stay in the core areas and blood to stay in the core areas and conserving heat conserving heat
Other FunctionsOther Functions
C) C) Cutaneous sensations: nervesCutaneous sensations: nerves in the skin in the skin allow us to feel pain, touch, pressure, heat, and allow us to feel pain, touch, pressure, heat, and cold cold
D) D) Metabolic functionsMetabolic functions - sunlight is converted - sunlight is converted into vitamin D in the skin; and several other into vitamin D in the skin; and several other chemicals are produced chemicals are produced
E) E) Blood reservoiBlood reservoir - 5% of the body's blood is in r - 5% of the body's blood is in the integument; when other areas of the body the integument; when other areas of the body need blood (i.e. during exercise), they can need blood (i.e. during exercise), they can "borrow" blood from the skin "borrow" blood from the skin
F) F) Excretion Excretion - nitrogeneous wastes are secreted - nitrogeneous wastes are secreted in sweat in sweat
Homeostatic ImbalancesHomeostatic Imbalances
BurnsBurns
1) Over 2,000,000 people are treated for 1) Over 2,000,000 people are treated for burns each year; about 12,000 of them die burns each year; about 12,000 of them die
2) There are 3 levels of burns. 2) There are 3 levels of burns. a) a) First-degree burnsFirst-degree burns - only the epidermis is - only the epidermis is
burned; least severe burned; least severe b) b) Second-degree burnsSecond-degree burns - the epidermis and - the epidermis and
upper dermis is burned; blisters occur upper dermis is burned; blisters occur c) c) Third-degree burnsThird-degree burns - epidermis and - epidermis and
dermis are burned; most severe; nerve dermis are burned; most severe; nerve damage (ends burned off); skin is blanched damage (ends burned off); skin is blanched (gray-white), red, or black; skin must be (gray-white), red, or black; skin must be replaced (grafting) replaced (grafting)
Skin CancerSkin Cancer
most often most often caused by UV caused by UV radiation, it radiation, it can be can be influenced by influenced by chemicals, chemicals, infections, infections, physical physical trauma trauma
Basal Cell CarcinomaBasal Cell Carcinoma
) the least malignant (cancerous; ) the least malignant (cancerous; spreads throughout the body) type spreads throughout the body) type
b) the most common type b) the most common type c) removal of the cancer area by c) removal of the cancer area by
surgery cures 99% of all cases surgery cures 99% of all cases
Squamous Cell CarcinomaSquamous Cell Carcinoma
a) starts in the keratinocytes of the a) starts in the keratinocytes of the stratum spinosum stratum spinosum
b) surgical removal and radiation b) surgical removal and radiation therapy cures most cases therapy cures most cases
Malignant MelonomaMalignant Melonoma
a) cancer of the a) cancer of the melanocytes melanocytes
b) the most dangerous b) the most dangerous type type
c) accounts for 5% of c) accounts for 5% of skin cancers skin cancers
d) 1/3 of cases d) 1/3 of cases develop from develop from pigmented moles pigmented moles
Assessment:Assessment:
Describe how the structure of the Describe how the structure of the skin helps it to protect the body, skin helps it to protect the body, maintain homeostasis, and serve as maintain homeostasis, and serve as an environmental barrier and an environmental barrier and temperature regulator. temperature regulator.