Download Integumentary Lecture

THE
INTEGUMENTARY
SYSTEM
I. Introduction
A. Basics
1. Consists of skin, hair, nails, and
cutaneous glands.
2. Largest organ of body
• 15-25 sq. ft
• 9 lbs
• 0.5-4.00 mm thick
• Lose ~ 40# skin in lifetime
B. Layers
1. Epidermis
• Epithelial t.
2. Dermis
• Connective t.
3. Hypodermis (subcutaneous t.)
• Loose connective t. (fat)
• Not part of the skin
• Anchors the skin to bone and
muscle tissue
C. Functions
protection
provides a barrier against microorganisms,
water, solar radiation, etc.
Vitamin D
Production
Synthesizes an inactive form of vitamin D
Sensation
Receives incoming messages/stimuli
Thermoregulation
Acts to maintain constant internal body temperature
Excretion (small amount)
Acts to excrete sweat, oil & milk
II. Epidermis
A.General
1.Keratinized,
stratified,
squamous
epithelium
2.New
epidermis
every 35-45
days
II. Epidermis
A. General
3. Callus – gross
thickening due
to friction
4. Blister – acute
trauma leads to
separation of
dermis and
epidermis
II. Epidermis
B. Cell types
II. Epidermis
B. Cell types
1. Keratinocytes cells that produce
fibrous protein keratin.
2.Keratin is a sulfur rich,tough, water
repellant protein
(the sulfur gives a distinct odor when hair, fur, skin or
leather burns)
3.protects the skin and the underlying
tissues from heat, microbes, abrasion
and chemicals
4.Produced in deepest layer
II. Epidermis
B. Cell types
B. Cell types
2. Melanocytes
•Produce pigment melanin
•Pigment is phagocytized by
keratinocytes
•Melanin protect keratinocytes from
UV radiation yet Excessive sun
exposure causes elastic fibers to
clump leading to leathery skin &
depresses skin immunity.
Normal skin color determinants
 Melanin
Yellow, brown or black pigments
 Carotene
Orange-yellow pigment from some
vegetables
 Hemoglobin
Red coloring from blood cells in dermis
capillaries
Oxygen content determines the extent of
red coloring
B. Cell types
3. Merkel’s cells
• Associated w/nerve cell
endings – touch reception in
fingertips
4. Langerhans’ cells
• Macrophage-like
• Defend against microorganisms
• Found in Stratum Spinosum
II. Epidermis
C. 5 Layers
Hint to remember the layers:
Can Little Girls Speak German
or British
• Can
• Little
• GiRls
• SPeak
• GERMan/
• British
Corneum
Lucidum
GRanulosum
SPinosum
GERMinativum
or Basale
II. Epidermis
1. Stratum Basalis
• AKA:Stratum Germinativum
• Single layer of cuboidal
cells
• Mitotic
•10-25% melanocytes
deposited here.
•Responsible for
generating the layers
above it
1. Stratum Basalis
• Receive nutrients by
diffusion from dermis
• Contains keratinocytes
melanocytes &
Merkel’s cells/disks (light
touch receptors)
•It takes 60-75 days for cells
in this layer to reach the
outermost surface
2. Stratum Spinosum
• Called the “Spiny or
prickly Layer” (8-10
layers thick)
• Less mitotic ~ less
nutrition received.
• Cells are many
sided keratinocytes
often called “Prickle
Cells”
2. Stratum Spinosum
• Scattered among
keratinocytes
are Langerhans’
cells (immunity
cells)
Note: The Stratum Basalis
and Stratum Spinosum
•contain the only epidermal cells
that receive adequate nourishment
by way of diffusion.
•As the daughter cells are pushed
upward, away from the source of
nutrition, they gradually die and
their soft protoplasm becomes
keratinized (hard).
•
•
•
•
3. Stratum
Granulosum
Layer has
granules w/i it’s
cytoplasm
Keratinization
begins
Cells begin to die
Thin layer 3-5 cell
layers
4. Stratum Lucidum
• Clear layer
• Found in thick
skin only as
palms and soles
of feet
• Contain Keratin
fibrils
• Cells begin to
degenerate
5. Stratum Corneum
•
•
•
Horny Layer
20-30 cell = ¾of
thickness.
Keratin in this layer
prevents water loss
due to lipids in
surrounding cells,
adds strength due
to keratinization &
exfoliaiton prevents
abrasion of cells.
5. Stratum Corneum
• Consists of dead flat
keratinized
cells being sloughed
off
• Forms from the
embryological
ectoderm germ
layer.
(stratified squamous)
(conreum means horn)
II. Epidermis
III. Dermis
skin’s body functions occur here
Known as the “true skin” because most of the
III. Dermis aka: hide
A. General
1. Strong,
flexible,
connective
tissue
2. Thickness:
0.6 – 3 mm
III. Dermis
A. Has collagen
gives skin
toughness & plumpness due to water attraction,
elastic
&
reticular fibers
give skin an elastic quality
(as we age, a
decrease in collagen & elastic fibers allows skin to sag)
B. Develops from
the mesoderm of
the embryological
germ layer.
A. General
Contains
•
•
•
•
•
•
•
Blood vessels
Nerves
Hair follicles
Sebaceous Oil glands
Sudiferous Sweat glands
Nail roots
Skin Appendages
A. General
Epidermis projects into
dermis to form dermal
Papillae.
Touch Receptors
Hair follicles
III. Dermis
B. 2 Layers: Papillary &
Reticular
B. Layers
1. Papillary
Layer
a. Closest to
epiderms
b. Made of areolar, loose con. t.
c. Has Dermal Papillae
• Finger-like projects that
indent into the epidermis
c. Has Dermal
Papillae
• Contain
Capillaries
pain receptors
Meisner corpuscles: sensitive to
light touch, discriminative touch, &
low vibrations. Allows you to gather
information about objects shape, texture, & density,
so your brain can identify the object
Finger prints
III. Dermis
B. Layers
2. Reticular
layer
a.Deepest layer
b.Comprises 4/5 of dermis
c.Made of dense irregular
connective tissue
III. Dermis
B. Layers
2. Reticular
layer
d.Rich in blood vessels and nerve
e. Pacinian corpuscles (Lamellated Corpuscles) – (egg shaped)
sensitive to deep tactile pressure & high
frequency vibration. Adapt rapidly. act as intestinal
& joint proprioceptors & enable you to detect the
object due to its weight
III. Dermis
B. Layers
2. Reticular
layer
d.Ruffini’s corpuscle senses heat
found skin & mouth
e.Krause’s End Bulb senses cold
found in mucus membrane of mouth
III. Dermis
B. Layers
2. Reticular
layer
f. Tension lines or cleavage –
separation of collagen
bundles
g. Flexure line – folding of
dermis at joints of wrists,
palms, fingers toes
Homeostatic Imbalance
• A decubitus ulcer (bed sore) can occur in bedridden
patients who are not turned regularly or who are
dragged across the bed repeatedly due to their own
body weight restricting the normal flow of blood to
the skin.
IV. Hypodermis aka
superficial fascia
1. Areolar and
adipose tissue
2. Contains lots of
Elastic fibers that
attach the skin to
the muscle below
3. Insulates, absorbs
shock, stores fat,
½ of body’s stored
fat is here.
IV. Hypodermis
1. Is absent or very
thin in the eyelids,
penis, scrotum &
nipples
True or False?
1. The dermis is the superficial layer of the skin.
2. The skin helps regulate body temperature.
3. The epidermis has three layers.
4. The hypodermis is above the dermis.
5. The skin protects against UV radiation.
Functions of Skin?
• The four main functions of the integumentary
system are: (Waste Excretion, Movement, Thermoregulation,
Protection, Sensation, Immunity)
1. Which function acts as a barrier against chemical,
mechanical, and microbial damage?
2. Which function acts to maintain constant internal
temperature?
3. Which function acts to receive stimuli from the
environment?
4. Which function acts to release sweat contains organic
chemicals, salts, and urea?
V. Skin Appendages
A.General
(4 embryonic categories: hair,
nails, nerves, & glands)
1. Organs that
develop
from the
embryonic
epidermis
2. Also called epidermal
derivatives
V. Skin Appendages
3.Includes
a.Hair
b.Sweat ,
sudoriferous,
glands
c.Sebaceous, oil,
glands
d.Finger nails
e.Tooth enamel
V. Skin Appendages
B. Hair
1. Is fused keratinized
cells
2. Protects against
• Scalp injury
• Sun
• Heat loss
3. Blonds have more hair
than dark haired people.
3. Hair
• Hair is a slender filament of mostly
dead keratinized epithelial cells that
grow from a follicle
• Is a derative of the modified stratum
corneum
• The hair consists of the medulla, a core
of loose cells and air spaces,
surrounded by a cortex, which is
densely packed keratinized cells.
• The cortex is covered by the cuticle.
3. Hair
•The bulb is a swelling at the
base where the hair originates;
the root is the remainder of the
hair within the follicle; and the
shaft is the portion of the hair
above the skin surface.
•Erector pili muscles are smooth
muscle
V. Skin Appendages
B. Hair
1. Is fused
keratinized
cells
2. Protects
against
• Scalp injury
• Sun
• Heat loss
B. Hair
3. Structure
a. Shaft
• Above
surface
• Shape
determines
curliness
– Round =
straight
– Oval = wavy
– Flat = kinky
Note:
The root
and
shaft
are
made of
3 tubes
Note: 3 tubes
• cuticle: outer tube
1 layer of heavily keratinized
cells.
• cortex: middle tube
several layers of cells w/ pigments in
dark hair and air bubbles in white
hair.
• medulla: inner tube
made of 2 -3 rows of cells with
pigments and air spaces.
B. Hair Follicle
• Hair Bulb Matrix
produces hair
• Inner epidermal
sheath made of
epithelial tissue
• Outer dermal
sheath made of
dermal connective
tissue.
• Arrector pili muscle
– goose bumps
V. Skin Appendages
B.Hair
4. Split ends – cuticle
wears away
5. Color results from melanin (black,
brown, yellow)
6. Hair growth/loss – depends on genes,
stress, illness, malnutrition, hormone levels,
some hair styles (ie tight braids), excessive
combing, & styling (w/use of hair chemicals)
& Excessive exercise
Cycle of Hair Growth
• Newly formed hair cells move up the follicle as
newer cells form beneath.
• As the cells dry out & fill w/keratin the hair cells
begin to harden & die.
V. Skin Appendages/ Hair
B. Kinds of hair
Lanugo – fine downy hair present in fetus and
replaced at birth.
Vellus hair: fine pale body hair of
women and children. Approx 2/3 of hair in ♀ and
1/10 in ♂ and all hair in children, except eyebrows,
eyelashes and scalp hair.
Terminal hair: coarse, pigmented male
body hair. Forms eyebrows, eyelashes, scalp
and pubic, axillary, and facial hair after puberty.
V. Skin Appendages
C.Nails
1. Scale-like
epidermal derivatives
2. Pink due to
capillaries in dermis
3. Fingernails grow
faster than toenails
C. Nails
3. Nail plate is
heavily karantinized
4. Nail body or
matrix is the nail
itself where mitosis
occurs.
5. Nail root is
responsible for
growth
C. Nails
C. Nails
Stratum basale extends beneath the nail
bed
The nail contains a free edge, a body, &
nail root.
Eponchium (cuticle) is the proximal nail
fold that projects onto the nail body.
Lunula is the half moon shaped portion of
the nail that lacks pigmentation.
Subungal Hematoma: blood clot beneath
the nail.
V. Skin Appendages/Exocrine Glands
D. Sudoriferous Glands = Sweat Glands
1. Two types: Eccrine or Merocrine & Apocrine
2. Both secrete sweat, which evaporates & cools the
body.
3. Sweat is odorless but when it mixes w/the skin’s
natural bacterial, sweat’s proteins & fats feed the
bacteria causing a musky, unpleasant odor.
4. Merocrine/Eccrine Glands–are the most numerous
& located all over the body especially in palms of the
hands & soles of the feet. (Mainly produce sweat which is mostly water
plus some salts, Vit. C, traces of metabolic wastes like ammonia & urea, & lactic acid therefore
it’s acidic.)
V. Skin Appendages/ Exocrine Glands
D. Sudoriferous Glands : Sweat glands
5. Apocrine Glands: located mostly in axillary & the
genital regions & around the anus. Secrete sweat that
contains fatty acids, proteins, which can give it a milky
or yellowish color. Usually begin functioning during
puberty & quit working in old age.
6. Mammary Glands are considered modified
apocrine sweat glands.
V. Composition & Function of Sweat
Glands
 Made mostly of water, some metabolic
wastes & fatty acids & proteins (apocrine)
 Function
Helps dissipate excess heat
Excretes waste products
Acidic nature inhibits bacteria growth
 Odor is from associated bacteria
D. Sudoriferous Glands
4. Function
• Assists in
maintaining
normal body
temp.
D. Sudoriferous Glands
5. specialized
sudoriferous
glands
• Mammary
glands
• Ceruminous
glands
Cerum
= earwax
D. Sebaceous Glands
 Sebaceous glands
Produce oil
Lubricant for skin
Kills bacteria
Most with ducts that empty into hair
follicles
Glands are activated at puberty
V. Skin Appendages
E. Ceruminous Glands
1. Produce Sebum
• Oil
• Prevents skin from
drying out
• Protects against
bacteria
2. Exocrine
Fill in the blanks with: hypodermis, keratinocytes,
sweat, or papillary.
1. Eccrine is a type of _______________ gland.
2. _______________ produce keratin.
3. Adipose tissue is found in the
_______________.
4. The _______________ of the dermis forms
fingerprints.
V. Skin Appendages
E. Tooth Enamel
1. the hard outer layer
of the tooth.
VI. Skin Color
A.Melanin
1. Made by
• melanocytes
• transferred to keratinocytes
2. Yellow to brown to black
3. Racial differences result of
kind and amount of melanin
A. Melanin
4.Builds up with sun
exposure protects
• Over exposure
 alters DNA  cancer
and/or leathery skin
 Not enough UV  to
break down of folic
acid (vit. B)  anemia
or neural tube defects
A. Melanin
4.Builds up with sun exposure
protects
• Under exposure
 MS
 Rickets
 Osteoporosis
B. Carotene
1.Yellow to orange
2.Found mainly in Corneum
Layer, soles, palms
C. Hemoglobin
1.In red blood
cells in
capillaries
2.Gives pinkish
hue to Caucasian skin
Note: Caucasian’s have less
melanin
VII. Other
A. Regulation of Body Temp.
1. Negative feedback system
2. Excessive Heat
• Vessels dilate
• Sweat evaporates from skin
3. Prevent heat loss
• Vessels constrict
• Arrector pili muscles cause
hair to stand on end
VII. Other
 Infections
Athletes foot
Caused by fungal infection
Boils and carbuncles
Caused by bacterial infection
Cold sores
Caused by virus
VII. Other
 Infections and allergies
 Contact dermatitis
 Exposures cause allergic reaction
 Impetigo
 Caused by bacterial infection
 Psoriasis
 Cause is unknown
 Triggered by trauma, infection, stress
VII. Other
B. Aging
1. Blood flow to skin
reduced
• Thins skin/ more easily
damaged
• Repair is slower
2. Sagging results from
• Elastic fibers reduce in
number & diameter
• Loss of subcutaneous
tissue
VII. Other
B. Aging
3. Age Spots
• Localized areas of
increased # of
melanocytes
4. Gray hair
• Decrease or lack of
melanin production
VII. Other
C. Skin Cancer
1.The most common
type of cancer
2. It occurs more often
in people with light
colored skin who have
had a high exposure to
sunlight.
Skin Cancer
 Cancer – abnormal cell mass
 Suffix “-oma” means tumor
 Two types
 Benign
 Does not spread (encapsulated)
 Malignant
 Metastasized (moves) to other parts of the
body
 Skin cancer is the most common type of cancer
Skin Cancer Moles
VII. Other
C. Skin Cancer
3. Signs of skin cancer
a. growth or a sore that
won't heal
b. a small lump.
• smooth, shiny and
waxy
• or it can be red or
reddish brown.
c. a flat red spot that is
rough or scaly.
Skin cancers
VII. Other
C. Skin Cancer
Most common type yet
least malignant:
a.Basal Cell
Carcinomas
b.Caused by
exposure to
the sun
Basal Cell Carcinoma
VII. Other
C. Skin Cancer
3. Frequent type:
b.Squamous Cell
Carcinoma
Metastasizes to lymph
nodes
Sun exposure
Lips of smokers
Early removal allows for
good chance of survival
Squamous Cell Carcinoma
VII. Other
C. Skin Cancer
3. Most deadly type:
c.Melanoma
• Most malignant
• Caused by sun
exposure
• Metastasizes
rapidly to lymph
and blood vessels
Melanoma
IV. Other
C.Skin Cancer
4. ABCD Rule to distinguish a
normal mole from a melanoma
• A ... Asymmetrical halves the
different halves of the mole don't look like
each other
• B ... Border irregularity
the
edges of the mole are indented or notched.
• C ... Color variation different
colors in pigmented area
• D ... Diameter
greater than the size
of a pencil eraser tip or 6mm
VII. Other
 Burns
 Tissue damage and cell death caused by heat,
electricity, UV radiation, or chemicals
 Associated dangers
 Dehydration
 Electrolyte imbalance
 Circulatory shock
Severity of a Burn
• Severity of a thermal
wound correlates directly
with:
– Temperature
– Concentration
– Amount of heat energy
possessed by the object or
substance
– Duration of exposure
Burn severity depends on:
1. Depth of burn
2. Extent of burn
3. Critical areas involved
• Face, upper airway,
hands, feet, genitalia
4. Preexisting medical
conditions
5. Patient younger than 5
or older than 55
VII. Other
D. Burns
1.
st
1
•
•
•
•
•
Degree, Mild, Superficial
Minor epithelial damage
Red, tender
Dry
No blisters
Mild Edema
Mild Burn
VII. Burns
2nd Degree, Moderate, Partial
Thickness
• Damage to epidermis and
superficial (papillary) dermis
• Pink, exquisitely tender
• Moist
• Blisters
• Heals in 2-3 wks w/o
scarring.
Partial
Thickness
Burns
Partial
Thickness
Burns
VII. Burns
D. 3rd Degree, Severe, Full-thickness
• Involves all 3 skin layers
• Color variable: white, waxy,
red, brown, red (scalds)
• Destroys elasticity
• Dry
• Painless
• Does not heal
Third Degree Burn
Rule of 9’s
– Used to estimate
surface area
affected by the
burn.
• Divide body into
9% sections
D. Burns
3. Rule of 9’s
•
•
•
•
•
•
Torso: 18%
Leg: 18%
Head: 9%
Arm: 9%
Genitalia: 1%
Palm: 1%
Critical Burns
 Burns are considered critical if:
 Over 25% of body has second degree
burns
 Over 10% of the body has third degree
burns
 There are third degree burns of the face,
hands, or feet
VII. HOMEOSTASIS & TISSUES
A. Inflammatory Response
1.Inflammation produces swelling,
redness, heat, tenderness, and a
loss of function at the inflamed
site.
VII. HOMEOSTASIS & TISSUES
A. Inflammatory Response
An infection is an inflammation
produced by an invading
organism, such as a bacterium.
B. Inflammatory Response
2. Sequence of Events
homeostasis disturbed 
mast cells release chemicals 
blood flow and permeability
increases 
clot formation isolates area 
phagocytes remove debris and
microorganisms 
homeostasis returns
Injury and Repair
•
•
The skin can regenerate after injury.
After injury there are four stages of healing:
1.
2.
3.
4.
After injury bleeding usually occurs into the site.
Clot or scab forms at the surface of the epidermis.
Granulation occurs and the clot dissolves.
Scar tissue forms and the extent of scarring depends on
the degree of the injury.
2 types of Tissue Repair
1. Regeneration
 Replacement of destroyed tissue by the
same kind of cells
2. Fibrosis
 Repair by dense fibrous connective tissue
(scar tissue)
 Determination method for repair type:
 Type of tissue damaged
 Severity of the injury
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 3.69
Events in Tissue Repair
 Capillaries become very permeable
 Introduce clotting proteins
 Wall off injured area
 Formation of granulation tissue
 Regeneration of surface epithelium
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 3.70
Regeneration of Tissues
 Tissues that regenerate easily
 Epithelial tissue
 Fibrous connective tissue and bone
 Tissues that regenerate poorly
 Skeletal muscle
 Tissues that are replaced largely with scar
tissue
 Cardiac muscle
 Nervous tissue within the brain and spinal cord
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 3.71
Developmental Aspects of Tissue
 Epithelial tissue arises from all three
primary germ layers
 Muscle and connective tissue arise from
the mesoderm
 Nervous tissue arises from the
ectoderm
 With old age there is a decrease in
mass and viabililty in most tissues
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 3.72
THE END