Integumentary intro Flashcards
list the 6 functions of the skin
- physical barrier
- temp regulation
- blood pressure
- secretory
- sensory
- protection
what are the 3 layers of the skin?
- epidermis
- dermis
- hypodermis/subcutis
what is the function of the epidermis?
primary protection/physical barrier against microbes, chemicals, toxins, and impact via formation of cornified envelope, production of antimicrobial substances, and permanent shedding of corneocytes
what skin layer is the primary envelope to contain water, electrolytes, and macromolecules?
epidermis
what are the 5 layers of the epidermis?
from deep to superficial:
1. stratum basale/germinativum
2. stratum spinosum
3. stratum granulosum
4. stratum lucidum
5. stratum corneum
what is found in the stratum basale? give tissue type
stem cells to produce all following layers, rests upon dermis; single layer of columnar or cuboidal epithelium; EUCHROMATIC
describe the stratum spinosum give tissue type
maturing keratinocytes are found here; keratinocytes produce keratin filaments that will kill the cell when enough are produced; cells shrink when plated but are held together by desmosomes so you can see their spines! polyhedral or squamous prickle cells
where is the stratum spinosum thick? where is it thin?
thick in regions where there is not hair, thin in regions with hair
describe the stratum granulosum; give tissue type
keratohyalin granules (clumped keratin filaments; soft keratin) are seen; cells also secrete lipids (lamellar bodies) to make skin waterproof and act like mortar between bricks for added protection; flat, squamous cells
describe the stratum lucidum; where is it found? give tissue type
only present in very thick tissue! will look clear since no like stain; found in foot pads or highly keratinized tissue; homogenous squamous cell layer
describe the stratum corneum; give tissue type
dried, horny cells in the process of being desquamated (turned into dander); layers of flat cornified cells lacking a nucleus
give what epidermal layers keratinocytes are proliferative, maturing, and inactive
proliferative: stratum basale
maturation: stratum spinosum and stratum granulosum (keratin filament and keratohyalin formation)
inactive: stratum lucidum and stratum corneum (lose nucleus, cell contents comapcted)
what are internal impacts to the epidermis? what is the result?
malnutrition or lack of essential fatty acids leads to epidermal lipid deficiency/disturbance which leads to scaling or poor barrier function
what are external impacts to the epidermis? what is the result?
excessive washing, chemical, and wet/dry environments weaken the epidermal barrier, leading to increased scaling and increased transepidermal water loss
what is the most numerous cell type in the integument?
keratinocytes
what do keratinocytes produce?
keratin
where are melanocytes located?
in the stratum basale and project into the stratum spinosum
what do melanocytes possess? how does this aid their function?
possess cytoplasmic processes of considerable length; these cells secrete pigment that their cytoplasmic processes inject into adjacent cells
describe the cytoplasm of melanocytes
clear and scant; usually mixed with pigment granules
what two pigments do melanocytes produce?
- eumelanin (black/brown)
- pheomelanin (orange/yellow)
responsible for skin and hair color
what are intraepidermal macrophages/Langerhan’s cells? describe their cytoplasm and where they are found
an immunologic link between outside environment and individual immune system; found in the strata basale and spinosum, but mainly spinosum; have clear cytoplasm with a round to irregular shaped nucleus
what are tactile epitheliod/Merkel cells? give function and describe cytoplasm and location
function not confirmed, but believed to be mechanoreceptors; clear cytoplasm with a pyramidal to flat nucleus parallel to epidermal surface; FOUND ONLY IN BASALE
what are the 2 layers of the dermis?
- papillary layer
- reticular layer
describe the papillary layer of the dermis; give cell types (5)
interdigitates with and increases cells on basement membrane; contains
1. fibroblasts
2. macrophages
3. plasma cells
4. mast cells
5. fat
describe the reticular layer of the dermis
a network of collagen, elastic fibers, and reticular fibers