Chapter 6 Flashcards
What are the layers of skin?
Epidermis
-Stratum corneum
-Stratum granulosm
-Stratum lucidum (palms & soles)
-Stratum spinosum
-Stratum basale/germinativum
Dermis
-Papillary layer
-Reticular layer
Describe stratum basale?
Deepenst layer of skin that is composed of a single row of stem cells that are attached to the dermis.
They are mitotic active and produce two daughter cells
Melanocytes compose 10-25% of this layer
Describe stratum spinosum?
Called the prickly layer. Several layers thick of cells containing intermediate prekeratin filaments attached to desmosomes.
Scattered amoung keratinocytes are dendritic cells which are APC that aid in immune function (carry invaders on head)
Describe stratum lucidum?
Only present in thick skin (palms and soles)
Describe stratum granulosum?
4-6 cell layers. Cells change by flattening, nuclei and organelles disintegrating, and keratinization beginimng. Cells above this layer die due to being too far from dermal capillaries
Describe stratum corneum?
20-30 rows of dead, flat, anucleate keratinized membranous sacs which comprise 3/4 of epidermal thickness that acts as protection
Describe melanocytes?
Located in stratum basale and produce the pigment melanin to absorb UV light from the sun and provide skin color
Describe tactile corpuscles?
Sensory receptors close to the surface of the skin that is sensitive to light touch as called Meissner’s corpuscles
Describe dendritic cells?
Part of the family of immune cells that capture (phagocyte), process, and present antigens to adaptive immune cells
Describe keratinocytes?
The major type of cell in the epidermis that receives and uses melanin
Describe pacinian corpuscles?
Detect pressuere also called lamellated corpuscles
Describe meissner’s corpuscles?
Detect light touch also called tactile corpuscles
What are the 3 pigments that influence skin color?
Melanin, carotene, and hemoglobin
Desciribe melanin?
Two two types. The common brownish-black is eumelanin and reddish-yellow pheomelanin. Skin color is determined by the amount produced. All people have the same number of melanocytes.
Describe carotene?
A yellow-orange pigment that accumulates in the stratum corneum and the hypodermis
Describe hemoglobin?
A protein that carries oxygen and when amount are rich provides a pinkish hue while if not enough present will result in a pale blueish-gray
Describe jaundice?
Skin becoming yellow because a liver dysfunction causes the build-up of bilirubin
Describe cyanosis?
Low hemoglobin causing the skin to appear blueish
Describe albinism?
A mutation in the melanin gene causes someone to have non-pigmented skin