Session 2 Skin Flashcards
Stratum Basale
Primary mitosis layer; partly responsible for constant renewal of underlying layers
produces abundant protein (rough ER)
Single cell layer on the basal lamina
Desmosome and hemidesmosomes isomers to attach layer to underlying layer
Produce cytokeratins (filaments)
Stratum Spinosum
A variety of cell shapes; cuboidal, polygonal, slightly squamous; partially mitosis
Tonofibrils: run through and create a “prickly” appearance; attach to the desmosomes interconnecting each cell (anchored here)
Thicker in areas of abrasion
Stratum Granulosum
Stains dark blue due to keratohyalin granules; lamellar granules as well
Start to lose mitosis ability;
Pumps out keratin!
Produces a waxy covering to resist dehydration (extra cellular cement)
Stratum Lucidum
More apparent in thick skin;
Extremely flattened cells (eosiniphilic cell) that lack protein synthesis
Densely packed cytokeratins filaments
Cells in a large amount of waxy coating; resist friction
Cells begin to die
Stratum Corneum
Flattened non-nucleated cells; dead keratinocytes
Filled with keratin and embedded in a matrix of keratohyalin granules;
Sloughs off easily; wax dried out and barely anchored by desmosomes
Epidermis
Epithelial layer (ectoderm); has ridges that interdigitates with dermis; contains keratinocytes, melanocytes, langerhan cells, and merkel cells
Dermis
connective tissue (mesoderm); has dermal papillae for interdigitation; has a rich blood supply, encapsulated nerve endings; hair, sweat, and sebaceous glands within epithelial invaginations
Peg and Socket Configuration of Interdigitation
A form the dermal/epidermal connection can take; seen in thin skin
Ridges and Groove Interdigitation
Seen in thick skin between dermis and epidermis
Hypodermis
deep to the dermis; subcutaneous loose connective tissue; contains adipocytes (fat cells); not part of the skin, but forms loose adhesion of skin to underlying tissue; the underlying tissue is covered by a fascia plane that has a variable appearance
Functions of Skin
receptor organ
protects against impact and friction
protection agains UV-pigment melanin
glands, blood vessels, and adipose; thermoregulation, body metabolism, and excretion
Keratinocytes
keratinizing epidermal cells
Langerhans Cells
part of the immune system; bone marrow derived macrophages; binds antigens
Merkel Cells
sensory receptors; within the thick skin; may be sensory due to association with free nerve endings; but most nerve endings are in the dermal layer of the skin
Thick Skin
smooth, non-hairy, on the palms and heels where lots of abrasion/friction occurs; the stratum lucidum as a marker for this type of skin
Thin Skin
hairy layer; covers most of the body; does not have a well developed lucidum
Melanocytes
neural crest in origin; found in and beneath stratum basale
Produces melanin; protects/darkens against UV damage; encircle the nucleus of the keratinocytes protecting the genetic material from UV radiation; melanin is packaged into vesicles that are extruded and picked up by cells;
Sun tanning speeds up the release of melanin
Papillary Layer of Dermis
contains dermal pegs to attach to epidermis
Reticular Layer of Dermis
dermatan sulfate elastic fiber network
Lamina Reticularis of Dermis
reticular fibers that contribute to basement membrane
Sebaceous Glands
produces sebum-fat of the gland and remnant of dead secretory cells-holocrine secretion (whole cell is secreted)
Begin to function at puberty; if plugged= acne
Ducted into hair follicle
Sweat Glands
eccrine and apocrine;
Eccrine Glands
open to the skin surface; simple coiled tubular glands; watery secretion produced as response to changes in body temperature
Apocrine Glands
larger and can extend all the way to the hypodermis; open to hair follicles; responsible for body odor; secretion is viscous and allows for bacterial decomposition
Actinic Keratosis
precancerous changes to corneal layer of epidermis; may turn into squamous cell carcinoma; also known as solar keratoses due to prevalence on exposed skin surfaces; arms, face, scalp
Squamos Cell Carcinoma
locally invasive, yet can metastisize
Basal Cell Carcinoma
most common type of epidermal cancer; destructive to local tissue
Malignant Melanoma
since melanocytes migrate into the epidermal layers, they readily will leave this tissue and travel throughout the body and invade all tissues and organs. This is a highly metastatic type of cancer
Wound Healing: Stages
immediate- blood floods to the area
Inflammation- immune system response
Proliferation- new vessles form in the area
Maturation
