INTEGUMENTARY SYSTEM
■ Epidermis about 0.1 mm
INTEGUMENTARY SYSTEM Function of the Skin
★ Consist of the skin and accessory organs; ★ Keratin
hair, nails, and cutaneous glands. ○ keratin
★ Inspection of the skin, hair, and nails is a ○ Dermaticidin and defensins
significant part of a physical exam. ○ Acid mantle
★ Skin is the most vulnerable organ ★ Other barrier functions
○ Exposed to radiation, trauma, ○ Water
infection, and injurious chemicals. ○ UV radiation
★ Receives more medical treatment than ○ Harmful chemicals
any other organ system. ★ Vitamins D synthesis
★ Dermatology - scientific study and ○ Skin carries out the first step liver
medical treatment of the integumentary and kidneys complete the process.
system ★ Sensation
○ Skin is an extensive sense organ
○ Receptors for temperature, touch,
pain, and more
★ Thermoregulation
○ Thermoreceptors
○ Vasoconstriction/ vasodilation
○ Perspiration
★ Nonverbal communication
○ Facial expressions
○ Importance in social acceptance
and self image.
Epidermis
The Skin and Subcutaneous Tissues ★ Epidermis - keratinized squamous
★ Skin is the body's largest and heaviest epithelium
organ. ○ Includes dead cells at the skin
○
2
Covers 1.5 to 2.0 𝑚 ; composes 15% surface packed with tough keratin
of the body weight protein.
★ LAYERS: ○ Lacks blood vessels
○ Epidermis: stratified squamous ■ Depends on the diffusion of
epithelium nutrients from underlying
○ Dermis: deeper connective tissue connective tissues
layer ○ Contains sparse nerve endings for
○ Hypodermis: connective tissues touch and pain.
layer below dermis (not part of the Cells of the Epidermis
skin, but associated with it) ❖ Five epidermal cell types
★ Skin thickness ranges from 0.5 to 6 mm ★ Stem Cells
○ Thick skin covers the front of ○ Undifferentiated
hands, bottoms feet. cells that give rise
■ Has sweat glands, but no to keratinocytes
hair follicles or sebaceous ○ In deepest layer of
(oil) glands epidermis ( stratum
■ Epidermis 0.5 mm thick basale)
○ Thin skin covers the rest of the ★ Keratinocytes
body ○ Great majority of
■ Possesses hair follicles, epidermal cells
sebaceous gland, and ○ Synthesize keratin
sweat glands.
, ★ Melanocytes ○Named for appearance of cells
○ Synthesize pigment melanin that after histological preparation
shields DNA from ultraviolet (spiny)
radiation. ○ Also contains some dendritic cells
○ Occur only in stratum basale but ★ Stratum granulosum
have branched processes that ○ Three to five layers of flat
spread among keratinocytes and keratinocytes
distribute melanin ○ Cells contain dark-staining
★ Tactile cells keratohyalin granules
○ Touch receptor cells associated ★ Stratum Lucidum
with dermal nerve fibers ○ Thin, pale layer found only in thick
○ In basal layer of epidermis skins
★ Dendritic Cells ○ Keratinocytes packed with clear
○ Macrophages originating in bone protein eleidin
marrow that guards against ★ Stratum corneum (surface layer )
pathogens ○ Several layers (up to 30) of dead
○ Found in stratum spinosum and scaly, keratinized cells
granulosum ○ Resists abrasion, penetration,
water loss.
The Dermis
Dermis - connective tissue layer beneath
epidermis
➔ Ranges from 0.2 mm (eyelids) to 4 mm
(palms, soles)
➔ Composed mainly of collagen
➔ Well supplied with blood vessels, sweat
glands, sebaceous glands, and nerve
endings.
➔ Houses hair follicles and nail roots
➔ Is the tissue of the facial skin to which
skeletal muscles attach and cause facial
expressions of emotion
Layers of Epidermis ➔ Has a wavy, conspicuous boundary with
★ Thin skin contains four strata; thick skin the superficial epidermis
contains five strata ◆ Dermal papillae are upward,
finger-like extensions of dermis
★ Stratum Basale ( deepest epidermal ◆ Epidermal ridges are downward
layer) waves of epidermis
○ A single layer or stem cells and ◆ Prominent waves on fingers
keratinocytes resting on the produce friction ridges of
basement membrane fingerprints
■ Stem cells divide and give
rise to keratinocytes that ★ Papillary layer - superficial zone of
migrate toward skill surface dermis
to replace lost cells ○ Thin zone of areolar tissue in and
○ Also contains a few melanocytes near the dermal papilla
and tactile cells ○ Allows for mobility of leukocytes
★ Stratum Spinosum and other defense cells
○ Several layers of keratinocytes ○ Rich in small blood vessels
joined together by desmosomes ★ Reticular layer - deeper and thicker layer
and tight junctions of dermis
■ Epidermis about 0.1 mm
INTEGUMENTARY SYSTEM Function of the Skin
★ Consist of the skin and accessory organs; ★ Keratin
hair, nails, and cutaneous glands. ○ keratin
★ Inspection of the skin, hair, and nails is a ○ Dermaticidin and defensins
significant part of a physical exam. ○ Acid mantle
★ Skin is the most vulnerable organ ★ Other barrier functions
○ Exposed to radiation, trauma, ○ Water
infection, and injurious chemicals. ○ UV radiation
★ Receives more medical treatment than ○ Harmful chemicals
any other organ system. ★ Vitamins D synthesis
★ Dermatology - scientific study and ○ Skin carries out the first step liver
medical treatment of the integumentary and kidneys complete the process.
system ★ Sensation
○ Skin is an extensive sense organ
○ Receptors for temperature, touch,
pain, and more
★ Thermoregulation
○ Thermoreceptors
○ Vasoconstriction/ vasodilation
○ Perspiration
★ Nonverbal communication
○ Facial expressions
○ Importance in social acceptance
and self image.
Epidermis
The Skin and Subcutaneous Tissues ★ Epidermis - keratinized squamous
★ Skin is the body's largest and heaviest epithelium
organ. ○ Includes dead cells at the skin
○
2
Covers 1.5 to 2.0 𝑚 ; composes 15% surface packed with tough keratin
of the body weight protein.
★ LAYERS: ○ Lacks blood vessels
○ Epidermis: stratified squamous ■ Depends on the diffusion of
epithelium nutrients from underlying
○ Dermis: deeper connective tissue connective tissues
layer ○ Contains sparse nerve endings for
○ Hypodermis: connective tissues touch and pain.
layer below dermis (not part of the Cells of the Epidermis
skin, but associated with it) ❖ Five epidermal cell types
★ Skin thickness ranges from 0.5 to 6 mm ★ Stem Cells
○ Thick skin covers the front of ○ Undifferentiated
hands, bottoms feet. cells that give rise
■ Has sweat glands, but no to keratinocytes
hair follicles or sebaceous ○ In deepest layer of
(oil) glands epidermis ( stratum
■ Epidermis 0.5 mm thick basale)
○ Thin skin covers the rest of the ★ Keratinocytes
body ○ Great majority of
■ Possesses hair follicles, epidermal cells
sebaceous gland, and ○ Synthesize keratin
sweat glands.
, ★ Melanocytes ○Named for appearance of cells
○ Synthesize pigment melanin that after histological preparation
shields DNA from ultraviolet (spiny)
radiation. ○ Also contains some dendritic cells
○ Occur only in stratum basale but ★ Stratum granulosum
have branched processes that ○ Three to five layers of flat
spread among keratinocytes and keratinocytes
distribute melanin ○ Cells contain dark-staining
★ Tactile cells keratohyalin granules
○ Touch receptor cells associated ★ Stratum Lucidum
with dermal nerve fibers ○ Thin, pale layer found only in thick
○ In basal layer of epidermis skins
★ Dendritic Cells ○ Keratinocytes packed with clear
○ Macrophages originating in bone protein eleidin
marrow that guards against ★ Stratum corneum (surface layer )
pathogens ○ Several layers (up to 30) of dead
○ Found in stratum spinosum and scaly, keratinized cells
granulosum ○ Resists abrasion, penetration,
water loss.
The Dermis
Dermis - connective tissue layer beneath
epidermis
➔ Ranges from 0.2 mm (eyelids) to 4 mm
(palms, soles)
➔ Composed mainly of collagen
➔ Well supplied with blood vessels, sweat
glands, sebaceous glands, and nerve
endings.
➔ Houses hair follicles and nail roots
➔ Is the tissue of the facial skin to which
skeletal muscles attach and cause facial
expressions of emotion
Layers of Epidermis ➔ Has a wavy, conspicuous boundary with
★ Thin skin contains four strata; thick skin the superficial epidermis
contains five strata ◆ Dermal papillae are upward,
finger-like extensions of dermis
★ Stratum Basale ( deepest epidermal ◆ Epidermal ridges are downward
layer) waves of epidermis
○ A single layer or stem cells and ◆ Prominent waves on fingers
keratinocytes resting on the produce friction ridges of
basement membrane fingerprints
■ Stem cells divide and give
rise to keratinocytes that ★ Papillary layer - superficial zone of
migrate toward skill surface dermis
to replace lost cells ○ Thin zone of areolar tissue in and
○ Also contains a few melanocytes near the dermal papilla
and tactile cells ○ Allows for mobility of leukocytes
★ Stratum Spinosum and other defense cells
○ Several layers of keratinocytes ○ Rich in small blood vessels
joined together by desmosomes ★ Reticular layer - deeper and thicker layer
and tight junctions of dermis
