1. 2 Integumentary System: Essential Learning(s) Skin and Its Tissues List the general functions of...
-
Upload
brett-warren -
Category
Documents
-
view
216 -
download
1
Transcript of 1. 2 Integumentary System: Essential Learning(s) Skin and Its Tissues List the general functions of...
1
2
Integumentary System:Essential Learning(s)
Skin and Its Tissues
List the general functions of the skin.
Describe the structure of the layers of skin.
Summarize the factors that determine skin color.
Accessory Structures of the Skin
Describe the accessory structures associated with the skin.
Explain the functions of each accessory structure of the skin.
3
Integumentary System:Essential Learning(s)
Regulation of Body Temperature
Explain how the skin helps regulate body temperature.
Healing of Wounds and Burns
Describe the events that are part of wound healing.
Distinguish among the types of burns, including a description of healing with each type.
Lifespan Changes
Summarize lifespan changes in the integumentary system.
Levels of Organization
Subatomic particles
Atom
Molecule
Macromolecule
Organelle
Cell
Tissue
Organ
Organ system
Organism
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Introduction:Integumentary System
5
• Two or more kinds of tissues grouped together and performing specialized functions constitutes an organ.
•The integumentary system consists of a major organ, skin, and many epidermal derivatives (accessory struc)which include hair follicles, sebaceous glands, sweat glands, and nails.
What is the function of the skin? What does it do?
Skin and Its FunctionsProtection:
Physical barriera. From water lossb. From injury c. From chemicals and microorganismsChemical barriera. ph of 5 – 6b. Prohibits microbial growthBiological barriera. Langerhan’s cells (epidermis) – function
with leukocytes to trigger immune
reactionsb. Macrophages and mast cells (dermis)
6
Skin and Its Functions
Protection: Surface film – produced by the mixing of residue and secretions from sweat and sebaceous glands with epithelial cells constantly being cast off from the epidermis
Functions: Antibacterial and antifungal activityLubricationHydration of skin surfaceBuffering of caustic irritantsBlockage of many toxic agents
7
Skin and Its FunctionsExcretion: (minimal, most through kidneys!)
through sweat - urea and uric acid
Regulation of Body Temperaturerecall negative feedback mechanism from Ch. 1
Cutaneous SensationLight touch detection = tactile (Meissner’s) corpuscles
a. egg-shapedb. Located in dermal papillaec. populate areas in the fingertips, palms, soles,
eyelids, tip of the tongue, nipples, clitoris, and tip of penisPressure detection = lamellated (Pacinian) corpuscles
a. Onion-shapedb. located in deep dermis and subcutaneous
regions8
Skin and Its Functions
Vitamin D synthesis:
UV rays in sunlight activate its synthesis
Vitamin D is required for bone homeostasis Blood Reservoir:
The dermis houses about 10% of the body’s blood vessels
Skin only requires 1 – 2% of the body’s blood
Immunity:
Langerhan’s cells (macrophages)
interact with T-helper cells in immune responses 9
Layers of Skin
10
• Epidermis - outermost layer of cells
• Dermis - inner layer
• Subcutaneous layer - adipose tissue
• A.k.a hypodermis• Beneath dermis
Stratifiedsquamousepithelium
Dense irregularconnectivetissue
Adipose tissue
Epidermis
11
(a)
Hair shaft
Epidermis
Hair follicle
(b)
Sebaceous gland
Dermis
Sweat
Epidermis
Dermis
Hair shaft
Sweat gland pore
Capillary
Stratum corneum
Stratum basale
Dermal papilla
Arrector pili muscle
Lamellated (Pacinian) corpuscle
Basement membrane
Sebaceous gland
Hair follicle
Sweat gland
Nerve cell process
Adipose tissue
Blood vessels
Muscle layer
Sweat gland duct
Subcutaneouslayer
T Tactile (Meissner’s) corpuscle
• Structure = keratinized stratified squamous epithelium
•Function = Protection (keratin) prevents water loss; prevents injury by penetration; prevents microbe/chemical entry
•Pigment = melanindetermines skin colorproduced by melanocytes in stratum basale
o genetic factorso environmental factorso physiological factors
b: © Victor Eroschenko
Epidermis
12
There are five (5) layers of the epidermis:• Stratum corneum – outermost layer• Stratum lucidum (only in thick skin – palms, soles)• Stratum granulosum – 3-5 layers of flattened granular cells (keratin)• Stratum spinosum - many layers of spiky cells w/ large nuclei• Stratum basale – innermost layer (directly above basement mem)
* Together the spinosum and basale make up the stratum germinativum
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
Basementmembrane
Dermis
Dermal papilla
(a) (b)
EpidermisStructure = keratinized stratified squamous epitheliumFour distinct layers
each determined by the extent of keratinization in the epithelial cells:
Stratum corneum = outermost layer dead epithelial cells filled with the protein keratin
Stratum lucidum = translucent layer separating s. corn & s. granextra layer only in thick skin of soles & palms
Stratum granulosum = composed of 3-5 layers of flattened granular cells (filled w/ keratin granules)
Stratum spinosum = composed of many layers of “spikey” cells with large nuclei
Stratum basale = innermost layer; directly above basement m.singe row of mitosing cuboidal cells & melanocytes
13
Epidermis
14
Genetic Factors• Varying amounts of melanin• Varying size of melanin granules• Albinos lack melanin
Environmental Factors• Sunlight• UV light from sunlamps• X-rays• Darkens melanin
Physiological Factors• Carotene may accumulate in
s. corneum = orange• Hb in dermal b vessels = pink• Lack of Hb = blue (cyanosis)• Inability to breakdown Hb (liver problem) = yellow
Pigment = melanina) determines skin colorb) produced by melanocytes in s. basale
Heredity and environment determine skin color
Dermis
15
Ex. nails, hair follicles and skin glands
Functions: A. nourishment of epidermis B. provides strength/flexibility
inner layer of skin; binds epidermis to underlying tissues
Structure: A. two distinct layers
1) papillary layer2) reticular layer
B. houses epidermal derivativesor accessory structures
(a)
Sweat
Epidermis
Dermis
Hair shaft
Sweat gland pore
Capillary
Stratum corneum
Stratum basale
Dermal papilla
Arrector pili muscle
Lamellated (Pacinian) corpuscle
Basement membrane
Sebaceous gland
Hair follicle
Sweat gland
Nerve cell process
Adipose tissue
Blood vessels
Muscle layer
Sweat gland duct
Subcutaneouslayer
Tactile (Meissner’s) corpuscle
Accessory structures of the Skin Nails:
1. structure: epithelia undergoing keratinization
(mitotically active in lunula)
2. functions:
a. manipulation
b. protection of ends of digits Hair follicles:
1. structure:
a. root or base in deep dermis
b. follicle throughout dermis
c. shaft in epidermis extending beyond the surface
16
Accessory structures of the Skin Hair follicles: cont
2. Keratinization
a. cell are epithelium
b. cells in root = mitotically active
c. cells in follicle = maturing & accum. keratin
d. cells in epidermis = dead epith. cells; full of keratin
= exposed hair or hair shaft
3. Pigment = melanin
a. albinism = lack of melanin
b. red hair = trichosiderin
4. Arrector pili muscle = bundle of smooth muscle assoc. w/
every hair follicle
a. causes hair to stand on end when frightened or cold
= “goose bump”
17
Accessory structures of the Skin Skin glands:
1. Sebaceous glandsStructure:
a. holocrine gland (simple cuboidal epith.)b. assoc w/ every hair folliclec. secretion = sebum (ie. oil) fat and cell
materialsebum is secreted into hair follicle
Function:a. sebum keeps skin/hair soft, pliable, &
waterproofDisorders:
a. acne (hypersecretion sebum;ducts clog & inflame)
b. seborrhea (hyperprod of sebum; oily scales)
18
Accessory structures of the Skin Skin glands: cont
2. Sweat glands & sudoriferous glands * Two types (based on glandular secretion)a. Merocrine (eccrine) glandsStructure: coil in deep dermis; duct in dermis; pore at surfaceCharacteristics: respond to elevated temp/exercise; no odor in secretion; function throughout life; not assoc w/ hair follicleLocation: forehead; neck; backSecretion: water + salts + waste (urea/uric acid)
19
Accessory structures of the Skin Skin glands: cont
2. Sweat glands & suboriferous glandsb. Apocrine glands Structure: ducts terminate into fair follicles Characteristics: respond to stress/emotions; odor in secretion;
function at puberty/continue thru life; assoc w/ hair follicles
Location: armpits & groin Secretion: sweat (as above) + oil + cellular debris Modified Apocrine glands: ceruminous gland=ear wax mammary
gland=milk
20
Dermis
21
1) Papillary layer (20%) a. superficial = below epidermis b. loose areolar CT c. dermal papillae here
form fingerprints in thick skin d. Meissner’s corpuscles
- light touch receptor
2) Reticular layer (80%) a. collagen/elastic/reticular
fibers = strength & resiliency b. cleavage, tension or
Langer’s lines are here c. Lamellated (Pacinian) corpuscles
– deep pressure receptors
Two layers of the dermis:
(a)
Papillary layer
Reticular layer
Subcutaneous Layer
22
Hypodermis
Structure:Loose connective
tissue and adipose tissue Function:
Insulates
Major blood vessels present(a)
Sweat
Epidermis
Dermis
Hair shaft
Sweat gland pore
Capillary
Stratum corneum
Stratum basale
Dermal papilla
Arrector pili muscle
Lamellated (Pacinian) corpuscle
Basement membrane
Sebaceous gland
Hair follicle
Sweat gland
Nerve cell process
Adipose tissue
Blood vessels
Muscle layer
Sweat gland duct
Subcutaneouslayer
Tactile (Meissner’s) corpuscle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Hair Follicles
23
• Epidermal cells
• Tube-like depression
• Extends into dermis
• Three (3) parts:• Hair root• Hair shaft• Hair papilla
• Dead epidermal cells
• Melanin• Arrector pili muscle
(a)
Hair shaft
Pore
Hair root(keratinizedcells)
Arrector pilimuscle
Sebaceousgland
Hair follicle
Region ofcell division
Hair papilla
Eccrinesweat gland
Dermal blood vessels
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Nails
24
Function: protective covering
Structure: Three (3) parts:
Nail plate
Nail bed
Lunula
Nail bed Nail plateLunula
Sebaceous Glands
25
Usually associated w/ hair follicles
Holocrine glands
Secrete sebum (oil)
Absent on palms and soles
Hair
Sebaceousgland
Hair follicle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
© Per H. Kjeldsen
Sweat Glands
26
• A.k.a sudoriferous glands
• Widespread in skin
• Originates in deeper dermis or hypodermis
• Eccrine glands
• Apocrine glands
• Ceruminous glands
• Mammary glands
Dermalpapilla
Sebaceousgland
Duct
Hair shaft
Hairfollicle
Eccrinesweatgland
Apocrinesweatgland
Pore
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Regulation of Body Temperature
27
1. Regulation of body temperature is vitally important because even slight shifts can disrupt metabolic reactions * Heat production is mostly a by-product of cellular metabolism
2. Heat loss controlled by regulating dermal blood flow a. vasodilation – increases dermal blood flow = incr. heat loss b. vasoconstriction – decreases dbf = decr. Heat loss 3. Four methods of heat loss
a. radiation – most heat loss; infrared heat rays move from
area of high heat (blood) to low heat (environ)
b. conduction – less heat loss; heat moves by phys contact
c. convection – heat loss to surrounding air; incr. as air moves
d. evaporation – heat loss varies; if heat incr. sweating incr.
lose heat by sweat evaporating on skin
Regulation of Body Temperature 4. Low body temperature requires heat loss to be
minimized
a. the hypothalamus signals for sweating to decrease
(decreasing heat loss by evaporation) and dermal
vasoconstriction (decreasing heat loss by radiation)
b. usu. brings body temp back to normal 5. If body temp remains low (after the above action)
a. heat must be produced
b. shivering occurs and the tiny muscle contrations
involved produce heat28
Regulation of Body Temperature Problems in Temperature Regulation
1. Hyperthermia = elevated body temperature
requires heat to be dissapated
a. Two common causes:
1. humid air decreases evaporation
2. air temp exceeds body temperature
heat is gained/ not lost
2. Hypothermia = low body temperature
a. very dangerous is core temp. drops below 94 F
b. limbs can withstand 65 F because they contain
no vital organs
c. intentional during some surgical procedures
29
Regulation of Body Temperature
30
If body temperaturecontinues to drop,control center signalsmuscles to contractinvoluntarily.
too high
too low
Normal bodytemperature37°C (98.6°F)
Control centerHypothalamusdetects the deviationfrom the set point andsignals effector organs.
Control centerHypothalamusdetects the deviationfrom the set point andsignals effector organs.
StimulusBody temperature risesabove normal.
EffectorsDermal blood vesselsdilate and sweat glandssecrete.
ResponseBody heat islost to surroundings,temperature drops towardnormal.
EffectorsDermal bloodvessels constrictand sweat glandsremain inactive.
EffectorsDermal bloodvessels constrictand sweat glandsremain inactive.
ResponseBody heat is conserved,temperature rises toward normal.
StimulusBody temperaturedrops below normal.
ReceptorsThermoreceptorssend signals to thecontrol center.
ReceptorsThermoreceptorssend signals to thecontrol center.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Healing of Wounds and Burns
31
A. Cuts1. Epidermal cuts are closed by increased cell
division in the stratum basale2. Deep cuts involve blood vessel damage resulting in: a. inflammation b. blood clotting c. scab formation d. fibroblast infiltration e. scab falls off f. scar may or may not form
B. Burns1. superficial partial- thickness burns (1st degree)
a. epidermis onlyb. reddening due to increased blood
flowc. mild paind. common in sunburne. heals in a few days to 2 weeks
Healing of Wounds and Burns B. Burns (cont)
2. Deep partial-thickness burns (2nd degree)
a. epidermis & some dermal damage
b. reddening and blistering (blood vessel damage)
c. moderate pain
d. common to physical contact w/ hot objects
e. heals in 2-6 weeks w/0 scars unless infected
3. Full-thickness burns (3rd degree)
a. epid., derm., and subcutaneal damage
b. dry, leathery tissue w/ red or black color
c. severe pain
d. caused by prolonged heat or chemical contact
e. healing rarely occurs due to lack of surviving skin
cells; grafts needed; usually extensive scarring
32
Healing of Wounds and Burns B. Burns…cont
3. Full-thickness burns (3rd degree)f. autograft – transplant from
undamaged area of selfg. homograft – temporary transplant
from cadaver4. Body surface affected
a. estimated by “rule of nines”b. important for determining
treatment/prognosis
33
34
(a) (b)
(f) (g)
(c) (d) (e)
Scartissue
Fibroblasts
Scartissue
Blood cells
Site of injury
Scab
Bloodclot
Scab
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Rule of Nines for Adults
35
Anteriortrunk18%
Posteriortrunk18%
Anterior upperextremities 9%
Posterior upperextremities 9%
Posterior lowerextremities 18%
Perineum 1%
Anterior andposterior upper
extremities18%
Anterior andposterior lower
extremities36%
100%
Anterior andposterior trunk
36%
Anterior and posterior head and neck9%
Anterior headand neck 41/2%
Posterior headand neck 41/2%
Anterior lowerextremities 18%
9% 9% 9% 9%
41/2%
41/2% 41/2% 41/2% 41/2%
41/2%
Lifespan Changes A. Aging skin exhibits:
1. wrinkling
a. some individuals choose “botox” injections to temp
reduce wrinkles
2. sagging
3. age spots or liver spots
B. Efficient regulation of body temperature declines w/ age
1. number of sweat glands changes
2. capillary beds in the skin shrink
C. Synthesis of vit. D declines as skin ages, which affects
skeletal health = ex. osteoporosis36
Lifespan Changes
37
• Skin becomes scaly• Age spots appear• Epidermis thins• Dermis becomes reduced• Loss of fat• Wrinkling• Sagging• Sebaceous glands secrete less oil
• Melanin production slows• Hair thins• Number of hair follicles decreases• Nail growth becomes impaired• Sensory receptors decline• Body temperature unable to be controlled• Diminished ability to activate Vitamin D