Lab module 5

epidermis

the outermost layer of skin

what are the five epidermal strata

1. corneum

2. lucid

3. granulosum

4. spinosum

5. basale

what is the stratum corneum

tough layer of dead, flattened cells containing keratin

what is the stratum lucidum

only in thick skin, strains clear/translucent/pinkish

what is the stratum granulosum

contains dark-staining keratohyalin granules

what is the stratum spinosum

keratinocytes appear “spikes”due to desmosomal connections

what is the stratum basale

contains skin stem cells and melanocytes, highly mitotic

what are the two layers of the dermis

papillary later and reticular layer

papillary layer

thin, superficial layer of dermis containing dermal papillae and capillaries

reticular layer

thicker, deep layer of dermis composed of dense irregular connective tissue

hypodermis

subcutaneous layer located under the skin (not part of the skin) composed mainly of adipose tissue

what are blood capillaries in the skin

tiny vessels supply nutrients and oxygen to skin tissues

dermal papillae

bumps that provide adhesion between dermis and epidermis

tactile (meissne’s corpuscles)

receptors for light touch

lamellar (Pacinian) corpuscles

receptors for deep touch and deep pressure

eccrine sweat glands

small, numerous sweat glands associated with temperature regulation through cooling

apocrine sweat glands

larger, less abundant sweat glands associated with body odor

sebaceous glands

secrete sebum (oil) to lubricates skin and hair

hair follicle

enclose and produce individual hairs

Hair root

deeper portion of a hair below the skin’s surface, enclose by a follicle

hair shaft

portion of a hair that erupts above the skin surface

arrector pili muscle

smooth muscle that pulls hair upright causing goosebumps

adipose tissue

fat tissue that stores energy and process insulation