Download KUMC 01 Integument Student

INTEGUMENT
Surface Anatomy
• Palpation
• Bony landmarks
• Dermatomes
Neural assessment
Integument Histology
• Epidermis:
Stratified squamous epithelium
Resting on:
• Basement membrane
Resting on:
• Dermis:
Dense irregular connective tissue
Epidermis
• The epidermis is a stratified squamous
epithelium.
• It is made up of many layers of cells.
• The stratum germinativum is the deepest
layer:
Area of high mitotic activity.
Epidermis
• The stratum corneum is the most
superficial layer:
The cells in this layer are dead and
keratinized.
• Between the stratum germinativum and
the stratum corneum are several
transitional layers represented by cells
from the stratum germinativum that are
transforming into dead, keratinized cells.
Epidermis
• The epidermis is innervated.
• The epidermis is avascular.
Dermis
• The dermis is the deepest region of the
integument.
• The dermis is classified as dense irregular
connective tissue
• The dermis has an abundance of collagen
fibers
• There may also be some elastic fibers:
Decrease with age.
Dermis
• The dermis is vascularized.
• Refer to Figure 1 in your course packet.
Thick Skin vs. Thin Skin
• Classification into thin and thick skin
depends on the structure of the epidermis.
• Layers of epidermis are well-formed in
thick skin.
• Layers of epidermis are not as well-formed
or thick in thin skin.
Thick Skin
• Thick skin is found only on the palms of
the hands and the soles of the feet.
• The epidermis of thick skin is 0.4 – 0.6 mm
thick
• Thick skin has no hair follicles.
Thin Skin
• Thin skin is found over the rest of the
body.
• The epidermis of thin skin is 0.075 – 0.150
mm thick.
• Total skin thickness is 0.5 – 3 mm thick.
Skin Thickness
• Thickest skin found on back (= thin skin)
• Thinnest skin found on eyelids (= thin skin)
• Thicker on extensor surfaces than flexor
surfaces.
Superficial Fascia: Synonyms
•
•
•
•
Subcutaneous fascia
Superficial fascia
Hypodermis
SubQ
Superficial Fascia
• Consists of loose bundles of collagen and
elastic fibers with variably sized
aggregations of lipocytes (fat cells)
• May be loosely or tightly attached
• Supports cutaneous nerves and blood
vessels
Deep Fascia
• Synonyms:
Membranous fascia
Investing fascia
• Usually several thin layers of tough
collagen material
• Tightly adherent to muscles, bones,
tendons, etc.
Cutaneous Derivatives
• Glands.
• Hairs.
• Nails.
Glands
• Glands are epithelial structures
• Glands are classified according to the
presence or absence of a secretory duct:
Exocrine
Endocrine
Epidermal Glands
•
•
•
•
Sudoriferous glands
Sebaceous glands
Ceruminous glands
Mammary glands
Sudoriferous Glands
• Are long, simple, tubular glands.
• Their method of secretion is merocrine .
Sebaceous Glands
• Are holocrine .
• Sebaceous glands are associated with
hair follicles.
Ceruminous Glands
• Are located in the external auditory canal.
• Secrete ear wax.
Mammary Glands
• Are modified sweat glands
• Method of secretion is apocrine
Hairs
• Hairs develop during 3rd month of
gestation.
• The earliest fine embryonic hair = lanugo.
• Lanugo is Shed before birth except around
eyebrows, scalp, and eyelids.
Hairs
• A new downy coat of hair appears a few
months after birth.
• This new coat is called vellus.
• Vellus is converted to terminal hair at
puberty:
Vellus represents 95% of the hair coverage
in males.
Vellus represents 35% of the hair coverage
in females.
Parts of a Hair
• Shaft:
Made up of dead cornified epidermal cells.
• Follicle:
Derived from both epidermis and dermis.
• Dermal papilla with matrix.
Parts of a Hair
• Arrector pili muscle.
• Sebaceous glands.
• Hair bulb and connective tissue papilla.
Hair Growth
• Anlagen
Active growth:
Scalp hair = 2-3 years
Eyebrow hair = 3-4 months
Hair Function and Location
• Hair follicles are innervated, and hairs
serve as sensory receptors.
• Hairs are found everywhere except palms,
soles, dorsal distal phalanges, anal and
urogenital apertures
Nails
• Ungis:
Modified stratum corneum
Flattened
Avascular and not innervated
Travels over a nail bed guided by lateral nail
grooves
• Matrix:
Stratum germinativum produces ungis
• Subungis
Melanocytes
• Found in deep layers of epidermis
• Derived from nervous system components
• Form:
Melanosomes:
Passed off to keratinocytes (cells of
epidermis).
Phagocytized by keratinocytes.
Melanocytes
• All individuals produce same number of
melanosomes.
• Skin color depends on number of
remaining melanosomes.
Langer’s Lines
• Represent tension lines created by
orientation of collagen fibers in the dermis
of the skin.
• Used by surgeons as guides for incisions:
Incisions normally made parallel to Langer’s
lines
Dermatomes
• Specific region of skin innervated by a
specific spinal cord level.
• Refer in syllabus to figure 3