Lecture 8 - Integument Flashcards
Layers of skin
Epidermis, dermis, and hypodermis (not apart of the integument)
What is present in thick skin
thicker stratum corneum and a presence of a stratum lucidum
4 Cells of the epidermis
keratinocytes, langerhan’s cells, merkel’s cells, and melanocytes
keratinocytes
filled with keratin fibers (intermediate), most common in the epidermis. connected via desmosomes. 5 layers.
Langerhan’s cells
derived from monocytes. can act as an APC and phagocytic cell
Merkel’s cells
sensory and typically next to a nerve. Has dense core ganules (neurotransmitter granules) next to the nerve ending
Melanocyte
produces the pigmentation of skin
5 layers of thick skin from top to bottom
Stratum corneum, stratum lucidum, stratum granulosm, stratum spinosum, and stratum basale
Most mitocially active layer
stratum basale and includes melanocytes
Protein in desmosomes
cadherins
Protein in hemidesmosomes
integrins
Stratum spinosum apperance
spiny cell layer due to tissue shrinkage and connection of desmosomes. tonofibrils and cytokeratin filaments present
Stratum granulosum appearance
due to keratohyalin (non-membrane bound granules) which bind to keratin. Lamellar granules (membrane) with lipids and is barrier to desiccation and water
Non-living cell layers
Stratum lucidum and stratum corneum
Layers in thin skin from top to bottoms
Stratum corneum, stratum granulosum, stratum spinosum, and stratum basale
3 functions of the epidermis
abrasion resistance, physical-chemical barrier, and water proofing
Melanocyte’s two pigments and enzyme
eumelanin (black) and pheomelanin (red). tyrosinase
Where do melanocytes originate from?
neural crests
Tyrosinase
synthesized in the RER. converts DOPA into doaquinone into melanin. stops when melanin becomes a granule
Where do melanin granules get injected?
into keratinocytes’ cytoplasm.
Role of melanin
protects the nuclear DNA from UV radiation
Albinism
lack of tyrosinase activity. Cant make melanin
T or F: skin color is due to the amount of melanin and carotene, not the number of melanocytes?
True
BCC
originates from the stratum basale
SCC
originates from a squamous keratinocyte
Collagen type found in the basement membrane
Type 4 collagen
Proteins and types of collagen seen on the dermal side of the dermal-epidermal junction
laminins, fibronectin, type 4 collagen, type 6 collagen
2 layers of the dermis
papillary and reticular layer. Makes up the peg and socket which provides stability.
Papillary layer
highly folded
Reticular layer
dense irregular CT (type I collagen and fibroblasts), blood tissues (AV shunts), and elastic fibers
Meissner’s corpuscles
sensory for light touch. Found in the papillary layer. Part of the afferent system
Arterio-venous shunts
short circulate blood, thus blood doesnt have to go through a capillary. control the blood going to the papillary layer (facilitates thermoregulation)
Pacinian corpuscle
deep touch/pressure sensation. In the reticular layer. Part of the afferent layer.
Hypodermis
superficial facia. adpiose tissue.
Nail matrix
gives rise to the nail plate.
Area under cuticle?
eponychium
Area under the nail plate
Hyponychium and nail bed
Hair is what in origin?
epidermal.
Bulb contains what dermal tissue
fibroblasts and blood vessels. It is papilla.
Germinal matrix
undergoing rapid proliferation of the forming hair cells. Sensitive to chemo
Internal root sheath
stops at the sebaceous gland
External root sheath
goes to the surface and becomes epidermis.
Cuticle of hair
small barbs that prevent it from falling out
Layer of hair from inner to outer
medulla, cortex, cuticle
Arrector pili muscle
smooth muscle. when cold it will contract, straightening the hair and increasing insulation. (fight or flight)
3 glands of skin
sebaceous, eccrine, and apocrine
Sebaceous glands
secrets onto hair shaft. simple branched acinar gland. Holocrine mode of secretion of sebum
Sebum
maintains stratum corneum, weak antibacterial/fungal activity
Eccrine sweat gland
Merocine and secretes onto the surface. Dark and clear cells. Duct portion is stratified cuboidal cells. Secretions mainly protein free filtrate.
Dark cells of eccrine gland
mucoid and antibacterial
Clear cells of eccrine gland
produce sweat. have an increased surface area
Apocrine sweat gland
merocrine and secretes onto the hair shaft. Larger diameter than eccrine glands. Found in auxillary areas. Only has dark cells (pheromones)
What layer is responsible for wrinkles
Dermis - specifically the reticular layer.
White part of the proximal nail fold?
Lunula
Area that has stratified cuboidal epithelium?
Duct of the eccrine sweat gland
