1. Skin and Body Membranes
Chapter Four
Skin and Body Membranes

2. Classification of Membranes
Epithelial
Cutaneous
Skin
Stratified squamous
Mucous (mucosa)
Lines cavities
Simple columnar
Serous
One layer
Simple squamous
Serous fluid
Parietal & Visceral
Lines body cavities
Around organs
Pleura & Pericardium

3. Functions of the Skin Protection Defense Prevention of Dehydration
Against disease
Insulates & cushions
UV protection
Chemical protection
Defense
1st line of defense
Prevention of Dehydration
Keratin
Keeps H2O in & out

4. Functions of the Skin Maintenance of Body Temp. Excretion of Wastes
Heat loss – sweat
Heat retention – blood flow
Excretion of Wastes
Salts
Urea
H2O
Reception of Stimuli
Touch, pressure, pain, cold, heat
Vitamin D Synthesis
Cholesterol molecules  Vitamin D (sunlight)

5. Layers of the Skin - integumentary
Epidermis
Strata
Stratum basale
Closest to dermis
Undergoes mitosis
Nutrients from diffusion
Stratum spinosum
Flattened cells w/ spines
Stratum granulosum
Granules w/ keratin
Stratum corneum
“horny”
20-30 cell layers
Soles. Palms, fingertips-stratum lucidum

8. Cell Types Keratinocytes Melanocytes Langerhans cell Make keratin
Make melanin
Secretes melanin – basale layer
Langerhans cell
Macrophages-eat foreign substances

9. Skin Color – amount and kind
Pigments
Melanin
Reddish brown, or black
Carotenes
yellow
Hemoglobin
rosy
Emotional
Redness (sympathetic)
Embarrassment
Anger
Fear
Allergies

10. Dermis – “hide” leather
Thick connective tissue layer beneath stratum basale.
Collagen
Elastin
Papillary layer
Upper, uneven
Receptors (pain, touch)
Dermal papillae
Fingers-fingerprints
Soles-footprints

11. Dermis cont… Reticular layer Deepest Blood vessels
Sweat and oil glands
Blood supply when restricted
Degeneration
Ulceration – bed sore

12. Appendages of the Skin Glands Sebaceous glands
Oil
Sebum: lubricant, bacteria killing
Whiteheads (blocked oil gland)  blackhead acne
Seborrhea – excess oil
Sweat glands – 500 ml a day (25 million)
Eccrine
Sweat
Clear
99% water
Salts, urea, lactic acid,
pH 4-6
Apocrine
Axillary & genital areas
Fatty acids, proteins, sweat (yellowish)
Empty into hair follicles

13. Appendages of the Skin cont..
Nails
Modified epidermal cells
Keratin
Hair
100,000 hairs scalp
Follicle
Keratinized cells
Arrector Pili (goose bumps)– smooth muscles -Hairs erect-increase blood flow to skin
Cuticle
Keep hairs separate

14. Infections and Allergies 1000 different conditions
Fungi
Athletes foot fungus
Ringworm
Bacterial
Boils and carbuncles
Staphylococcus into hair follicles
Oil glands
Impetigo
Viruses
Herpes “cold sores”
Warts

15. Allergies Unknown Yeasts Eczema Contact dermatitis “rash” Psoriasis
Hives
Yeasts

16. Skin in Stress Wound Repair Wound Inflammatory reaction Edema Clots
Blood flow
Edema
swelling
Clots
Stop bleeding
WBC’s
Fight bacteria
Pus
Dead blood cells
Dead bacteria
Scabs

17. Skin in Stress cont… Burns Thermal First degree Second degree
Heat
Chemical – electrical - UV
First degree
Epidermis “red”
Heal 2-3 days
Second degree
Epidermis & dermis
Blisters
Third degree
Skin blackens
Skin grafts
Risk of death
Fluid loss , imbalance of electrolytes
Kidney failure
Replace proteins , infection

19. Skin Cancer Basal Cell Carcinoma Squamous Cell Carcinoma
Most common
Alters stratum basale cells
Uncontrolled mitosis can’t form keratin
Squamous Cell Carcinoma
Stratum spinosum
Scaly reddish papulae
Spreads to lymph nodes
Malignant Melanoma – (5%)
Brown black patches
Lymph & blood vessels
ABCD rule moles
Asymmetrical, border, color, diameter 76mm

20. Disease States Erythema Pallor, blanching Jaundice Porphyria Bruises
Turns red
Pallor, blanching
Anemia
Low blood pressure
Jaundice
Yellowing
Liver disorder
Porphyria
purple
Bruises
Hematoma
Broken capillaries
Cyanosis
“bluish”
Low 02 in blood