Transcript PowerPoint to accompany Hole’s Human Anatomy and

CHAPTER 6 INTEGUMENTARY SYSTEM
1
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.
2
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.
3
Levels of Organization
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Subatomic particles
Atom
Organ system
Molecule
Macromolecule
Organ
Organelle
Organism
Cell
Tissue
Introduction:
Integumentary System
• 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?
5
Skin and Its Functions
 Protection:
Physical barrier
a. From water loss
b. From injury
c. From chemicals and microorganisms
Chemical barrier
a. ph of 5 – 6
b. Prohibits microbial growth
Biological barrier
a. Langerhan’s cells (epidermis) – function with
leukocytes to trigger immune reactions
b. 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 activity
 Lubrication
 Hydration of skin surface
 Buffering of caustic irritants
 Blockage of many toxic agents
7
Skin and Its Functions
 Excretion: (minimal, most through kidneys!)
through sweat - urea and uric acid
 Regulation of Body Temperature
recall negative feedback mechanism from Ch. 1
 Cutaneous Sensation
Light touch detection = tactile (Meissner’s) corpuscles
a. egg-shaped
b. Located in dermal papillae
c. populate areas in the fingertips, palms, soles, eyelids, tip
of the tongue, nipples, clitoris, and tip of penis
Pressure detection = lamellated (Pacinian) corpuscles
a. Onion-shaped
8
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
• Epidermis - outermost layer
of cells
• Dermis - inner layer
• Subcutaneous layer adipose tissue
• A.k.a hypodermis
• Beneath dermis
Stratified
squamous
epithelium
Dense irregular
connective
tissue
Adipose tissue
10
Epidermis
• Structure = keratinized stratified
squamous epithelium
Hair shaft
•Function = Protection (keratin)
prevents water loss; prevents
injury by penetration; prevents
microbe/chemical entry
Sweat gland pore
Sweat
Stratum corneum
Epidermis
Stratum basale
Capillary
Dermal papilla
Basement membrane
TTactile (Meissner’s) corpuscle
Dermis
Sebaceous gland
Arrector pili muscle
Sweat gland duct
Lamellated (Pacinian) corpuscle
Hair follicle
•Pigment = melanin
determines skin color
produced by melanocytes in
stratum basale
o genetic factors
o environmental factors
o physiological factors
Sweat gland
Subcutaneous
layer
Nerve cell process
Adipose tissue
Blood vessels
Muscle layer
(a)
Hair shaft
Epidermis
Dermis
Hair follicle
Sebaceous gland
(b)
b: © Victor Eroschenko
11
Epidermis
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
Basement
membrane
Dermal papilla
Dermis
(a)
(b)
12
Epidermis
 Structure = keratinized stratified squamous epithelium
 Four 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. gran
extra 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
Pigment = melanin
a) determines skin color
b) produced by melanocytes in s. basale
 Heredity and environment determine skin color
 Genetic Factors
• Varying amounts of
 Physiological Factors
melanin
• Carotene may accumulate in
• Varying size of melanin
s. corneum = orange
granules
• Hb in dermal b vessels = pink
• Albinos lack melanin
• Lack of Hb = blue (cyanosis)
 Environmental Factors
• Inability to breakdown Hb
• Sunlight
(liver problem) = yellow
• UV light from sunlamps
• X-rays
• Darkens melanin
14
Dermis
 inner layer of skin; binds epidermis to underlying tissues
Structure:
A. two distinct layers
1) papillary layer
2) reticular layer
B. houses epidermal derivatives
or accessory structures
Epidermis
Hair shaft
Sweat gland pore
Sweat
Stratum corneum
Stratum basale
Capillary
Dermal papilla
Basement membrane
Ex. nails, hair follicles and
skin glands
Dermis
Subcutaneous
layer
 Functions:
A. nourishment of epidermis
B. provides strength/flexibility
Tactile (Meissner’s) corpuscle
Sebaceous gland
Arrector pili muscle
Sweat gland duct
Lamellated (Pacinian) corpuscle
Hair follicle
Sweat gland
Nerve cell process
Adipose tissue
Blood vessels
Muscle layer
(a)
15
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
17
= “goose bump”
Accessory structures of the Skin
 Skin glands:
1. Sebaceous glands
Structure:
a. holocrine gland (simple cuboidal epith.)
b. assoc w/ every hair follicle
c. secretion = sebum (ie. oil) fat and cell material
sebum is secreted into hair follicle
Function:
a. sebum keeps skin/hair soft, pliable, & waterproof
Disorders:
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) glands
Structure:
coil in deep dermis; duct in dermis; pore at surface
Characteristics:
respond to elevated temp/exercise; no odor in
secretion; function throughout life; not assoc w/
hair follicle
Location:
forehead; neck; back
Secretion:
water + salts + waste (urea/uric acid)
19
Accessory structures of the Skin
 Skin glands: cont
2. Sweat glands & suboriferous glands
b. 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=milk20
Dermis
Two layers of the dermis:
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
Papillary layer
2) Reticular layer (80%)
Reticular layer
a. collagen/elastic/reticular
fibers = strength & resiliency
b. cleavage, tension or
Langer’s lines are here
c. Lamellated (Pacinian) corpuscles
– deep pressure receptors
(a)
21
Subcutaneous Layer
 Hypodermis
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 Structure:
Loose connective tissue
and adipose tissue
Epidermis
Dermis
 Function:
Insulates
Hair shaft
Sweat gland pore
Sweat
Stratum corneum
Stratum basale
Capillary
Dermal papilla
Basement membrane
Tactile (Meissner’s) corpuscle
Sebaceous gland
Arrector pili muscle
Sweat gland duct
Lamellated (Pacinian) corpuscle
Hair follicle
Subcutaneous
layer
Sweat gland
Nerve cell process
Adipose tissue
Blood vessels
Muscle layer
 Major blood vessels present
(a)
22
Hair Follicles
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• Epidermal cells
• Tube-like depression
• Extends into dermis
• Three (3) parts:
• Hair root
• Hair shaft
• Hair papilla
Hair shaft
Pore
Sebaceous
gland
Arrector pili
muscle
Hair root
(keratinized
cells)
Hair follicle
Eccrine
sweat gland
• Dead epidermal cells
• Melanin
• Arrector pili muscle
Region of
cell division
Hair papilla
Dermal blood
vessels
(a)
23
Nails
 Function: protective covering
Lunula Nail bed Nail plate
 Structure:
Three (3) parts:
Nail plate
Lunula
Nail bed
24
Sebaceous Glands
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 Usually associated w/ hair
follicles
Sebaceous
gland
Hair follicle
 Holocrine glands
 Secrete sebum (oil)
Hair
 Absent on palms and soles
© Per H. Kjeldsen
25
Sweat Glands
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• A.k.a sudoriferous glands
• Widespread in skin
Hair shaft
• Originates in deeper dermis
or hypodermis
• Eccrine glands
• Apocrine glands
• Ceruminous glands
• Mammary glands
Pore
Dermal
papilla
Sebaceous
gland
Duct
Hair
follicle
Eccrine
sweat
gland
Apocrine
sweat
gland
26
Regulation of Body Temperature
 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
27
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 heat
28
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
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Control center
Hypothalamus
detects the deviation
from the set point and
signals effector organs.
Receptors
Thermoreceptors
send signals to the
control center.
Effectors
Dermal blood vessels
dilate and sweat glands
secrete.
Stimulus
Body temperature rises
above normal.
Response
Body heat is
lost to surroundings,
temperature drops toward
normal.
too high
Normal body
temperature
37°C (98.6°F)
too low
Stimulus
Body temperature
drops below normal.
Receptors
Thermoreceptors
send signals to the
control center.
Response
Body heat is conserved,
temperature rises toward normal.
Effectors
Dermal blood
vessels constrict
and sweat glands
remain inactive.
Control center
Hypothalamus
detects the deviation
from the set point and
signals effector organs.
Effectors
Dermal blood
vessels constrict
and sweat glands
remain inactive.
If body temperature
continues to drop,
control center signals
muscles to contract
involuntarily.
30
Healing of Wounds and Burns
 A. Cuts
1. Epidermal cuts are closed by increased cell division in the
stratum basale
2. 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. Burns
1. superficial partial- thickness burns (1st degree)
a. epidermis only
b. reddening due to increased blood flow
c. mild pain
d. common in sunburn
e. heals in a few days to 2 weeks
31
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 self
g. homograft – temporary transplant from cadaver
4. Body surface affected
a. estimated by “rule of nines”
b. important for determining treatment/prognosis
33
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Site of injury
Blood cells
(a)
(b)
Scab
Blood
clot
(c)
(d)
(e)
Scab
Scar
tissue
Scar
tissue
Fibroblasts
(f)
(g)
34
Rule of Nines for Adults
41/2%
Anterior and posterior head and neck
9%
41/2%
Anterior head
and neck 41/2%
Anterior
trunk
18%
Anterior and
posterior upper
extremities
18%
Anterior upper
extremities 9%
41/2%
41/2%
Anterior and
posterior trunk
36%
Posterior head
and neck 41/2%
Posterior
trunk
18%
Posterior upper
extremities 9%
41/2%
41/2%
Perineum 1%
9%
Anterior lower
extremities 18%
9%
9%
Anterior and
posterior lower
extremities
36%
100%
9%
Posterior lower
extremities 18%
35
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. osteoporosis
36
Lifespan Changes
• 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
37