Anatomy and Function of the Skin

functions of the skin

1) protection

2) fluid conservation

3) temperature regulation

4) sweat regulation

5) sensation

6) immune assist

7) mobility assist

8) gives physical appearance/identity

20 ft2

How large would the average human's skin be if you laid it out flat?

layers of the skin

EPIDERMIS

1) stratum corneum

2) stratum lucidum

3) stratum granulosum

4) stratum spinosum

5) stratum basal

DERMIS

1) papillary

2) reticular

SUBCUTANEOUS TISSUE

epidermis

outermost layer of skin

FUNCTION--> barrier/protection from water loss

COMPOSITION:

1) 90% keratinocytes

(strength)

2) melanocytes

(gives skin color)

3) Langerhans

(immunity)

AVASCULAR

free nerve endings, Merkel

What 2 sensory receptors can be found in the epidermis?

HINT: pain, light touch

corneum, lucidum, granulosum, spinosum, basale

List the epidermal layers from outermost to innermost.

(excluding the word stratum)

HINT: My corny lucid grandma left her spine in the basement.

stratum lucidum

Which layer of the epidermis is only found on the palms and soles?

HINT: layer #2

stratum granulosum

In which layer of the epidermis do free nerve endings terminate?

HINT: layer #3

stratum spinosum

In which layer of the epidermis are there a high concentration of Langerhans cells?

HINT: layer #4

stratum basale

In which layer of the epidermis are melanocytes, Merkel cells, and epidermal cell germination?

HINT: layer #5

basement membrane

layer of collagen below the stratum basale and immediately superior to the dermis

FUNCTION--> bond the two skin layers together

*rete ridges

sweat glands, hair follicles, sebaceous glands

What are the 3 epidermal appendages?

HINT: move through epidermal layers

sweat glands

EPIDERMAL APPENDAGE

1) apocrine

location: axilla and groin

function: possible sexual attraction

2) eccrine

location: all over body except lips and external genetalia

function: regulate body temperature excretion of water and electrolytes

hair follicle

EPIDERMAL APPENDAGE

dips deep into reticular dermis

FUNCTIONS

1) follicle-->

re-epithelialization

(stem cells migrate to wounds to initiate healing process)

2) shaft-->

thermoregulation, UV, protection, protection from foreign particles, sensation

3) arrector pili-->

thermoregulation and emotion

sebaceous glands

EPIDERMAL APPENDAGE

incorporated within each hair follicle

FUNCTION--> secrete sebum

1) MOISTURIZING

2) water resistance

3) acidic pH of skin

(4-6)

false (sebum)

True or False: Sweat helps to moisturize the skin.

dermis

innermost layer of skin

FUNCTION--> protect the deeper layers and support/nourish the epidermis

COMPOSITION:

1) fibroblasts

2) extracellular matrix

3) adipocytes

4) lymphocytes

VASCULAR

papillary dermis

DERMAL LAYER

LOCATION:

superficial dermal layer

*rete ridges*

COMPOSITION

cellular:

- ECM

- loose collagen

- elastin

extracellular:

- lymphatic capillaries

- blood capillaries

- Meissner's corpuscles

(movement)

reticular dermis

DERMAL LAYER

LOCATION:

deep dermal layer

*80% of thickness*

COMPOSITION

cellular:

- ECM

- dense collagen

- elastin bundles

extracellular:

- arterioles

- venules

- pre-collectors

- Ruffini endings (stretch)

- Pacinian corpuscles (vibration)

subcutaneous (hypodermis)

located deep to the dermis

FUNCTION--> thermoregulation and cushioning to deep vital structures

COMPOSITION:

1) adipose tissue

- acts as insulation

- stores calories, gives skin motility, provides the body shape

2) fascia

- bands of collagen

- stabilize underlying structures

skin aging effects

REDUCED:

- dermal blood flow

- production of elastin and collagen fibers

- subcutaneous fat

- (flattening of) rete ridges

- sensory structures

- presence of Langerhans cells

- (delayed) wound healing

*sweat and sebaceous gland atrophy

(affects thermoregulation & skin moisture)

thin transparent film

Skin tears are typically a DRY wound. Which type of bandage should be applied for healing?

papillary dermis

Where do the blood and lymphatic capillaries live?

flattening of rete ridges

Why are skin tears more common with age?