chapter 6-Integumantary system

Layers of Skin

1. Epidermis

2. Dermis

3. Subcutaneous

Epidermis

• stratified squamous epithelium

• no direct blood supply

Stratum Basale

• layer closest to the basement membrane

• attachment of the epidermis to the dermis

• nourished by underlying connective tissue

• cells that travel upward and die and become keratinized (water proof)

Basal Cell Carcinoma

• most common human cancer

• found in sun exposed areas of the skin

Stratum Corneum

• Outer most layer of dead cells

• a barrier between the deeper layers of skin and the outside environment,

• prevents toxins and bacteria from entering the body

Melanocytes

• cell release melanin(pigment) to color skin

Eumelanin

• brownish black pigment

Pheomelanin

• reddish yellow pigment

Melanin

• Protects the deeper tissues from ultraviolet light

• Genetics & UV light affects skin color

• Blood in dermis may affect skin color

Melanoma

• most deadly skin cancer

watch for the ABCs

1. Asymmetry

2. Color

3. Diameter

4. Evolution

Dermis

• Binds and supplies blood to epidermis

• location of nerves (touch) hair folicles, Oil (sebaceous) glands, & sweat glands

• fibrous connective tissue with collagen(strength) & elastin (elasticity)

Subcutaneous

• loose connective and adipose(insulation& padding)

Hair

• Found on all surfaces except palms,soles,lips,nipple & external genitalia

• The root is at the bottom of an epidermal depression

• Nourished by the blood vessels from the dermis

• color from genetic- amount of melanin present

• smooth muscle(involuntary) attached to each hair follicle

• Muscle contracts, shortens & hair stands on end= goose bumps

Sebaceous Glands

• usually attached to hair follicle

• holocrine gland secretes oily mixture keeps skin soft and water proof

• acne is caused by overactive sebaceous glands

Nails

• protection covers ends of fingers and toes

• keratinized stratified squamous epithelium cells

• nail root- location of cellular division

• Lunula(white half moon shaped area) growing region

• nail bed- nail attached too

Sweat Glands

• Eccrine Glands- not associated with hair follicles

• found in forehead,neck & back ( most abundant) in palms of hands & soles of feet

• responds to rise of body temp

• sweat is released onto surface of the skin via pore

• Apocrine glands-associated with hair

• found in armpits & groin(most abundant in pubic region)

• begin functioning at puberty

• ear wax formed by modified glands of this type
  

Burn Information

1.Common Symptoms-

*Redness

*swelling

*pain

*peeling of skin

*shock

*white or charrded skin

First Degree-(superficial Parcial-thickness)effect outerlayer[epidermis], notice redness very sensitive to touch, skin will appear blanched when light pressure is applied. involve minimal tissue damage Sunburn is a good example of a first-degree burn.

Second Degree-(deep partial thickness)affect both the outer layer(epidermis) & underlying layer (dermis)causing redness, pain, swelling and blisters. affect sweat glands, and hair follicles.If not properly treated, swelling and decreased blood flow in the tissue can result in the burn becoming a third-degree burn.

Third-degree- (full thickness)affect the epidermis, dermis and hypodermis, causing charring of skin or a translucent white color, with coagulated vessels visible just below the skin surface. Healing from third-degree burns is very slow due the skin tissue and structures being destroyed. Third-degree burns usually result in extensive scarring.

Functions of the skin

1. Protection- from water loss, disease,& injury

2. sensory-temperature & touch

3. Vitamin D Production-makes its way to the skin with UV exposure

4. Regulation of body Temperature-

   *Normal body temp is 98.6

   *Increase of body temp = Hyperthermia-Body triggers the dermal blood vessels to relax [vasodilation:vas(o)-vessel] and the heat dissipates to the outside. Sweat glands release fluid onto the skin surface as fluid.

   *Decrease of body temp = Hypothermia- Blood vessels contract which decreases blood flow to reduce heat loss. Sweat glands become inactive. Skeletal muscle contract to release heat(shiver)

5. Healing of Wounds-

   1. Inflammation- Red swollen;caused by blood vessels dilating and forced fluids to leave the vessels this provides nutrients & oxygen to an area.

   2.Shallow Break- epithelial cells fill in gap

   3.Deep Break- [into dermis/subutaneous] scab forms, then fibroblast form new collagens;binds edges together, phagtonic cells remove dermis

   4. New connective tissue may be seen (scar)

Sebum

produce thick oily substance to stay moisturizerized

Dermatitis

inflammation of the skin

arrector pili

smooth muscle cause goosebumps

pressure ulcer

usaaly found over joints

cause by low blood suply cells die

Serous Membrane

This membrane type lines body

cavities that lack openings to the

outside (parietal/visceral).

Mucous Membrane

This membrane type lines body

cavities that open to the outside.

Vitamin D

depends on the skin

skin diagram

1. epidermis

2. dermis

3. subcutaneous layer/ hypodermis

4. hair shaft

skin diagram

5. Arrector Pili

6. hair folicle

7. sweat glands

8. nerve fiber

9. adipose cells

10. blood vessels