Transcript AandP skin

The
System
SKIN
The Integumentary System
Integument is
 Skin and its appendages make up the
integumentary system
 A fatty layer (hypodermis) lies deep to it
 Two distinct regions

Functions of skin

Protection
 Cushions
and
and is waterproof
 Protects from chemicals, heat, cold, bacteria
 Screens UV
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Synthesizes
Regulates body heat
Prevents unnecessary
Sensory reception (
cutaneous receptors)
with UV
loss
endings-
Epidermis
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Keratinized stratified squamous epithelium
Four types of cells
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– deepest, produce keratin (tough fibrous protein)
(protects and waterproofs)
Melanocytes - make dark skin pigment
Merkel cells – associated with sensory
endings
cells – macrophage-like dendritic cells
Layers (from deep to superficial)
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Stratum basale or germinativium – single row of cells attached to
dermis; youngest cells w/rapid growth,
forms here
Stratum spinosum – spinyness is artifactual; tonofilaments
(bundles of
) resist tension
Stratum granulosum – layers of flattened keratinocytes producing
keratin (hair and
made of it also)
Stratum
(only on palms and soles)
Stratum
– horny layer (cells dead,old cells, many
layers thick, translucent, flake off)
: layers (on left) and cell types (on right)
Remember…
 Four
basic types of tissue
– epidermis just discussed
Connective tissue – dermis

Nervous
tissue
Dermis
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Strong, flexible connective tissue: your “hide”
Cells: fibroblasts, macrophages, mast cells,
Fiber types: collagen,
,
reticular
Rich supply of
Critical role in temperature regulation (the
vessels)
Two layers (see next slides)
– areolar connective tissue;
includes dermal papillae
 Reticular – “reticulum” (network) of collagen and
reticular
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*Dermis layers
*Dermal papillae
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Epidermis and dermis of (a) thick skin and (b) thin skin
(which one makes the difference?)
Fingerprints,
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, footprints
Dermal papillae lie atop dermal ridges
Elevate the overlying epidermis into epidermal ridges
Are “sweat films” because of
pores
determined
creases
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Deep dermis, from continual folding
Fibers
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: strength and resilience
Elastic fibers: stretch-recoil
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Striae: stretch marks
Tension lines (or lines of cleavage)
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The direction the bundles
of fibers are directed
The dermis is the receptive
site for the pigment of tattoos
Hypodermis
“Hypodermis” (Gk) = below the
 “Subcutaneous” (Latin) = below the skin
 Also called “superficial
”
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“fascia” (Latin) =band; in anatomy: sheet of connective
tissue
Fatty tissue which stores fat and
skin (areolar tissue and adipose cells)
 Different patterns of accumulation
(male/female)
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Skin color
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Three skin pigments
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 Carotene:
from
 Hemoglobin: the

: the most important
and yellow vegies
of light skin
Melanin in granules passes from
melanocytes (same number in all races)
to keratinocytes in stratum
 Digested
by
 Variations in color (High conc. = freckles)
 Protection from UV light vs vitamin D?
Skin appendages
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Derived from epidermis but extend into
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Include
 Hair
and hair follicles (made of epithelial &
connective tissue)
 Sebaceous (oil) glands (most active at
puberty)
 Sweat (
) glands
 Nails
Nails
Of hard
 Corresponds to hooves and claws
 Grows from nail
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Hair and hair follicles: complex
Derived from epidermis and dermis
Everywhere but palms, soles, nipples, parts of genitalia
are tiny muscles
Attached to hair follicls to pull
“arrector pili” is smooth muscle
Hair upright during fright or cold
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Functions of hair
– less in man than other mammals
 Sense light touch of the skin
 Protection 
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Parts
 Root
imbedded in skin
 Shaft projecting above
surface
Make up of hair – hard
 Three concentric layers
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 Medulla
(
)
 Cortex (surrounds medulla)
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(single layers, overlapping)
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Types of hair
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: fine, short hairs
 Intermediate hairs
 Terminal: longer,
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Hair growth: averages
mm/week
 Active: growing
 Resting phase then
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Hair loss
–
 Male pattern baldness
 Thinning
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related
Hair color
 Amount
of melanin for black or brown; distinct form of
melanin for
 White: decreased
and air bubbles in
the medulla
 Genetically determined though influenced by
hormones and environment
Sebaceous (
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) glands
Entire body except palms and soles
Produce sebum by holocrine secretion
Oils and
Sweat glands
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Entire skin surface
except nipples and
part of external
genitalia
Prevent overheating
cc to 12 l/day!
(is mostly water)
Humans most
efficient (only
have)
Produced in
response to
as well as heat
Types of sweat glands
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Eccrine or
 Most
numerous
 True sweat: 99% water, some salts, traces of waste
 Open through pores
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Apocrine
 Axillary,
anal and genital areas only
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open into hair follices
 The organic molecules in it decompose with time - odor
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Modified apocrine glands
– secrete
 Mammary – secrete milk
 Ceruminous
Disorders of the integumentary system
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Burns
 Threat
to
Catastrophic loss of body fluids

and fatal circulatory shock
 Infection
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 Types
First degree – epidermis: redness (e.g.
)
 Second degree – epidermis and upper dermis: blister
 Third degree 
Infections
 Skin cancer
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Burns
First-degree
(epidermis only; redness)
Second-degree
(epidermis and dermis,
with blistering)
Third-degree
(full thickness, destroying
epidermis, nerve endings,
dermis, often part of
hypodermis)
Critical burns
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Over
of the
body has thirddegree burns
25 % of the body
has seconddegree burns
Third-degree
burns on face,
hands, or
Estimate by “rule of 9’s”
Body is
divided
Into 9%
regions
Scabies
Female mites burrows into
the
where she
lays eggs
 Skin-skin contact
 Clothing, bedding, towels
 Inflammatory elevation of
the skin (
papules)
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Scabies
Sysptoms:
- intense itching
- skin rashes
- produces allergic reaction (eggs)
- scratching may cause secondary
infection
 To help:
medications all
over the body
Ringworm
Ringworm
Fungal infection…not a worm!
 Skin-skin contact
 Ring-shaped, scaly
patches on the skin
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Ringworm
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Symptoms:
- red raised itchy
patches with defined
edges, lighter in the
center
- take an appearance
of a
To help:
- topical antifungal
drugs
Impetigo
Superficial skin infection
 Bacterial…staphylococcu
s or streptococcus
 Spread w/ direct contact
w/
 Thick, yellow crust
(commonly on the face)
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Infected Wounds
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Symptoms:
- swelling
- pain
- fever w/
- bleeding or pus
- foul smell
To help:
cleaning
- ABX and pain killers
Tumors of the skin
Benign, e.g. warts
 Cancer – associated with
(also skin aging)

exposure
keratosis – premalignant
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cell - cells of stratum basale, slow
 Squamous cell – keratinocytes. epithelial
 Melanoma – melanocytes: most dangerous;
recognition:
 Aktinic
A - Asymmetry
 B - Border irregularity
 C  D - Diameter larger than 6 mm
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Skin Cancer
Sqaumous cell carcinoma
Basal cell carcinoma
Melanoma
The Anatomy of a Tattoo
6-35
Ink Matures
Fibrin clot
Granulation Tisssue
6-37
Histology of a Tattoo
Epidermis
Dermis
Granulation tissue
INK
6-38
So where is my tattoo?
6-39
Bad Ink
Bad sterilization
6-40
6-41
6-42