Download Chapter 5

Chapter 5
Integumentary System
5-1
Integumentary System
• Consists of:
–
–
–
–
Skin
Hair
Nails
Glands
• Functions
–
–
–
–
–
Protection
Sensation
Temperature regulation
Vitamin D production
Excretion
5-2
Hypodermis
• Skin rests on this,
but not a part
• Consists of loose
connective tissue
• Types of cells
– Fibroblasts
– Adipose cells
– Macrophages
• Also called
– Subcutaneous tissue
– Superficial fascia
5-3
Skin
• Dermis
– Structural strength
– Cleavage lines
– Two layers
• Reticular
• Papillary
• Epidermis
– Avascular
– Cells
– Layers or strata
5-4
5-5
Cleavage or Tension Lines
• Elastin and collagen
fibers oriented in
some directions
more than others
• Important in
surgery
– If incision parallel
to lines there is less
gapping, faster
healing, less scar
tissue
5-6
Dermis and Epidermis
5-7
Epidermal Cells
• Cell types
–
–
–
–
Keratinocytes: Produce keratin for strength
Melanocytes: Contribute to skin color
Langerhans’ cells: Part of the immune system
Merkel’s cells: Detect light touch and pressure
• Desquamate: Older cells slough off
• Keratinization: Cells die and produce outer
layer that resists abrasion and forms
permeability layer
5-8
Epidermal Strata
• Stratum Basale
– Deepest portion of epidermis and single layer
– High mitotic activity and cells become keratinized
• Stratum Spinosum
– Limited cell division
• Stratum Granulosum
– In superficial layers nucleus and other organelles
degenerate and cell dies
• Stratum Lucidum
– Thin, clear zone
• Stratum Corneum
– Most superficial and consists of cornified cells
5-9
Epidermal Layers and Keratinization
5-10
5-11
Thick and Thin Skin
• Thick skin
– Has all 5 epithelial strata
– Found in areas subject to pressure or friction
• Palms of hands, fingertips, soles of feet
• Thin skin
– More flexible than thick skin
– Covers rest of body
5-12
Skin Color
• Determined by 3 factors
– Pigments
• Melanin: Provides for protection against UV light
• Albinism: Deficiency or absence of pigment
• Carotene: Yellow pigment
– Blood circulating through the skin
• Imparts reddish hue and increases during blushing,
anger, inflammation
• Cyanosis: Blue color caused by decrease in blood
oxygen content
– Thickness of stratum corneum
5-13
5-14
Accessory Skin Structures
• Hair
– Found everywhere on human body except palms, soles,
lips, nipples, parts of external genitalia, and distal
segments of fingers and toes
• Glands
–
–
–
–
Sebaceous or oil glands
Sudoriferous or sweat glands
Ceruminous glands
Mammary glands
• Nails
5-15
Hair Structure
• Composed of shaft
and root
– Shaft protrudes
above skin surface
– Root located below
surface and base
forms the hair bulb
• Has 3 concentric
layers
– Medulla: Central axis
– Cortex: Forms bulk
of hair
– Cuticle: Forms hair
surface
5-16
5-17
5-18
Hair Growth, Color, and Muscles
• Hair Growth
– Cycles
• Growth and resting
– Permanent hair loss
• Pattern balding most common
• Hair Color
– Caused by varying amounts and types of melanin
• Muscles
– Arrector pili: Muscle contraction causes hair to “stand
on end”
5-19
Oil and Sweat Glands
• Sebaceous glands
– Produce sebum
– Oils hair and skin
surface
• Sudoriferous glands
– Merocrine or eccrine
• Most common
• Numerous in palms and
soles
– Apocrine
• Found in axillae,
genitalia, around anus
5-20
5-21
5-22
Nails
• Anatomy
– Nail root proximally
– Nail body distally:
Eponychium or
cuticle
• Growth
– Grow continuously
unlike hair
5-23
5-24
5-25
Burns
• Classifications
– First-degree
– Second-degree
– Third-degree
• Skin Grafts
– Split skin
– Artificial skin
– Cadavers or pigs
5-26
The Rule of Nines
5-27
Aging Effects
• Skin more easily damaged
• Skin becomes drier
• Functioning melanocytes decrease or
increase as with age spots
• Sunlight ages skin more rapidly
5-28
Clinical Disorders
• Bacterial infections
– Acne
• Viral Infections
– Chicken pox, German measles, cold sores
• Decubitus ulcers or bedsores
– Ischemia and necrosis
• Cancer
– Basal cell carcinoma
– Squamous cell carcinoma
– Malignant melanoma
5-29
5-30
5-31
5-32
5-33
5-34