3 Layers of skin and what makes up each 

Epidermis, Dermis, Hypodermis

Epidermis: stratified squamous epithelium

contains melanocytes, Langerhans cells, Merkel cells

Dermis: connective tissue; superficial (papillary)dermis has areolar CT, deep (reticular) dermis has dense irregular CT

Hypodermis (subcutaneous): loose CT with adipose (not considered part of the skin) 

5 Layers of Thick (Glabrous) Skin 

Stratum basale (germanativum)

-superficial to basal lamina, high degree of mitotic activity 

Stratum Spinosum 

-abundance of keratin, tonofibrils help resist abrasion

Stratum Granulosum

-3-5 layers thick, contains lamellar granule which helps prevent drying out (dessication)

Stratum Lucidum

-translucent keratinocyte layer,no nuclei or organelle

Stratum Corneum

-keratinocyte cells w/out nuclei; horn cells are only protein + membrane - continuosly exfoliated 

Does thin skin contain stratum lucidum?

stratum granulosum?

stratum corneum? 

-no stratum lucidum in thin skin

-granulosum reduced or absent

-corneum reduced in thickness 

What are the 2 types of pigment produced by melanocytes and where are they found? 

eumelanin is found in dark brown hair

pheomelanin is found in red hair 

True or false:

Melanocytes are anchored to keratinocytes by desmosomes 

False:

melanocytes not anchored to keratinocytes

furthermore, not anchored to anything with desmosomes (anchored to basal lamina with hemidesmosomes) 

Where do Langerhans cells reside and what do they do? 

Reside in stratum spinosum of epidermis and help the immune response by processing and presenting antigens to T-lymphocytes

Glabrous skin contains which of the following:

hair

sweat glands

sebaceous glands 

Glabrous (thick) skin does not contain hair, does contain abundant sweat glands, and does not contain sebaceous glands

Describe the 2 types of sweat glands: 

Eccrine glands are coiled and open to the surface of the epithelium. Stratified cuboidal epithelium of ducts transmit merocrine (watery) secretion. Secretory portion in dermis surrounded by myoepithelium that contracts to help secrete product.

Apocrine glands secrete by merocrine method. Present in axillary, areolar + anal regions. Viscous secretion deposited into hair follicles under hormonal influence.

What glands develop at puberty and are under the control of sex hormones? 

Sebaceous glands

-holocrine 

-ducts from acini open to hair follicle or skin surface

-form sebum  

3 basic parts of the hair shaft 

medulla - central portion of hair shaft; partially keratinized and vacuolated cells

cortex -surrounds medulla; heavily keratinized and compacted root cells

cuticle - outermost layer; cuboidal cells become columnar toward upper portion of bulb, flatten as hair grows

What provides nourishment for hair follicle? 

the network of capillaries in the dermal papilla 

What produces the hair shaft? 

the hair root (the epidermal cells covering the dermal papilla) 

Part of hair that corresponds to stratum basale?

external root sheath

Part of nail that corresponds to stratum corneum of skin? 

The name of the actual stratum corneum around the nail? 

nail plate, or "nail" itself 

cuticle, or eponychium 

Where in hair does keratinization take place? 

only at hair root 

How is hair keratin different from skin keratin? 

Hair keratin is more compact than skin keratin