THE
INTEGUMENTARY
SYSTEM
I. Introduction
A. Basics
1. Consists of skin, hair, nails,
and cutaneous glands.
2. Largest organ of body
• 15-20 sq. ft
• 9 lbs
• 0.5-4.00 mm thick
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
1. protection
2. Vitamin D
production
3. Sensation
4. Thermoregulation
5. Excretion (small amount)
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
a.Produce fibrous protein keratin
• tough, water repellant protein
• protects the skin and the
underlying tissues from heat,
microbes, abrasion and
chemicals
b.Produced in deepest layer
II. Epidermis
B. Cell types
B. Cell types
2. Melanocytes
• Produce
pigment
melanin
• Pigment is phagocytized by
keratinocytes
• Pigment granules protect
keratinocytes from UV
radiation
B. Cell types
3. Merkel’s cells
• Associated w/nerve cell
endings – touch reception
• Scattered among
Kerantinocytes
4. Langerhans’ cells
• Macrophage-like
• Defend against
microorganisms
II. Epidermis
C. Layers
Hint to remember the layers:
Can Little Girls Speak German
• Can
• Little
• GiRls
• SPeak
• GERMan
Corneum
Lucidum
GRanulosum
SPinosum
GERMinativum
II. Epidermis
C. Layers
1. Stratum Basalis
• Also known as
Stratum
Germinativum
• Single layer
• Mitotic
C. Layers
1. Stratum Basalis
• Receive
nutrients by
diffusion from
dermis
• Composed of
columnar
keratinocytes
melanocytes
Merkel’s cells
C. Layers
2. Stratum Spinosum
• Called the
“Spiny Layer”
• Less mitotic
• Cells are many
sided
keratinocytes
often called
“Prickle
Cells”
C. Layers
2. Stratum Spinosum
•Scattered
among
keratinocytes
are
Langerhans’
cells
Note: The Stratum Basalis
and Stratum Spinosum
•contain the only epidermal cells
that receive adequate nourishment
•As the daughter cells are pushed
upward, away from the source of
nutrition, they gradually die and
their soft protoplasm becomes
keratinized (hard).
C. Layers
3. Stratum
Granulosum
• Granular layer
• Keratinization
begins
• Cells die
• Thin layer 2-3
cell layers
C. Layers
4. Stratum Lucidum
• Clear layer
• Found in thick
skin only as
palms and
soles of feet
• Contain
Keratin fibrils
• Cells begin to
degenerate
C. Layers
5. Stratum
Corneum
• Horny Layer
• 20-30 cell
layers
• ¾ of thickness
C. Layers
5. Stratum
Corneum
• Consists of
dead flat
keratinized
cells being
sloughed off
II. Epidermis
III. Dermis
III. Dermis
A. General
1. Strong,
flexible,
connective
tissue
2. Thickness:
0.6 – 3 mm
III. Dermis
A. General
3. Has
collagenous
& reticular
fibers
A. General
4. Contains
•
•
•
•
•
•
Blood vessels
Nerves
Hair follicles
Sebaceous glands
Sweat glands
Nail roots
A. General
5. Epidermis
projects
into
dermis to
form
• Sebaceous
glands
• Sweat glands
• Hair follicles
III. Dermis
B. Layers
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: light
touch receptors
• 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 – sense
deep pressure, heat and cold
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
IV. Hypodermis
1. Areolar and
adipose tissue
2. Anchors skin to
organs
3. Insulates,
absorbs shock,
stores fat
V. Skin Appendages
A.General
1. Organs that
develop
from the
embryonic
epidermis
2. Also called epidermal
derivatives
V. Skin Appendages
A.General
3. Includes
a.Hair
b.Sweat
glands
c.Sebaceous
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
B. Hair
3. Structure
a. Shaft
• Above
surface
• Shape
determines
curliness
– Round =
straight
– Oval = wavy
– Flat = kinky
3. Structure
a. Shaft
b. Root
• Extends
from
epidermis
to dermis
• Extends
into
hypodermis
in scalp
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
4. Follicle
• Provides
nutrients
• Matrix
produces
hair
• 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 – nutrition,
hormones
V. Skin Appendages
B.Hair
7. Kinds of hair
• Vellus hair: fine pale body
hair of women and children
• Terminal hair: coarse,
scalp, pubic region, male
body hair
P141 hirsutism
V. Skin Appendages
C.Nails
1. Scale-like
epidermal
derivatives
2. Pink due to
capillaries
in dermis
C. Nails
3. Nail plate is
heavily
karantinized
4. Nail bed
mitosis in
matrix
responsible
for growth
V. Skin Appendages
D. Sudoriferous
Glands
1. Sweat glands
2. Exocrine
3. everywhere
except lips,
nipples and parts
of external
genitalia
D. Sudoriferous Glands
4. Function
• Assists in
maintaining
normal body
temp.
D. Sudoriferous Glands
5. specialized
sudoriferous
glands
• Mammary
glands
• Ceruminous
glands
Cerum
= earwax
V. Skin Appendages
E. Ceruminous Glands
1. Produce Sebum
• Oil
• Prevents skin from
drying out
• Protects against
bacteria
2. Exocrine
VI. Skin Color
A.Melanin
1. Made by
• melanocytes
• transferred to keratinocytes
2. Yellow to orange to brown
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
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.
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.
VII. Other
C. Skin Cancer
3. Most frequent
types:
a.Basal Cell
Carcinomas
• Caused by
exposure to
the sun
VII. Other
C. Skin Cancer
3. Most frequent
types:
b.Squamous Cell
Carcinoma
• Sun exposure
• Lips of smokers
VII. Other
C. Skin Cancer
3. Most frequent
types:
c.Melanoma
• Most malignant
• Caused by sun
exposure
IV. Other
C.Skin Cancer
4. ABCD Rule to distinguish a
normal mole from a
melanoma
• A ... Asymmetrical lesions
• B ... Border irregularity
• C ... Color variation
• D ... Diameter greater than
the size of a pencil
eraser tip
VII. Other
D. Burns
1.
st
1
Degree
• Minor epithelial
damage
• Red, tender
• Dry
• No blisters
VII. Other
D. Burns
2. 2nd Degree
• Damage to epidermis
and superficial
(papillary) dermis
• Pink, exquisitely
tender
• Moist
• Blisters
VII. Other
D. Burns
3.
rd
3
Degree
• Involves all skin layers
• Color variable: white,
waxy, red, brown
• Destroys elasticity
• Dry
• Painless
• Does not heal
D. Burns
3. Rule of 9’s
•
•
•
•
•
•
Torso: 18%
Leg: 18%
Head: 9%
Arm: 9%
Genitalia: 1%
Palm: 1%
THE END