8. Integument Flashcards
What are the two steps of the production of melanin listed in the lecture?
Tyrosine -> DOPA (tyrosinase)
DOPA -> Melanin (polymerization)
What four main cell types are contained in the Stratum Basale?
Keratinocytes
Stem Cells
Melanocytes
Merkel Cells
Which sweat glands are activated during puberty?
Apocrine sweat glands
What layer of skin can only be seen in thick skin?
Stratum Lucidium
What part of the melanocyte extends into the cell processes?
The melanosome
How is the melanin producing enzyme induced to produce more melanin?
It is UV sensitive
What layer of the skin is constantly shed?
Stratum Corneum
Where can one identify Langerhans Cells?
In the Stratum Spinosum
Why might superficial Stratum Corneum cells be less able to attach to one another than deeper cells of the epidermis?
Because the lowered pH is unfavorable to cell junctions
What would you find at the core of a pacinian corpuscle?
A Myelinated Neuron
What changes define a cell of the Stratum Corneum as we travel up through the layers?
Loss of organelles
Becoming full of mature keratin
What do we call the bundles of keratin filaments in the basal layer?
Tonofibrils
What is a “cornified” cell?
A cell that is full of keratin
What binds the most basal cells of the stratum basale to the dermis?
Hemidesmosomes
What cells provide “acute sensory perception” for light touch?
Merkel Cells
What sort of secretion do Apocrine Sweat Glands use?
Merocrine secretion
(despite the name)
Why is the Stratum Lucidium named as such?
Because it appears “clear” relative to other layers.
What classification of epithelial tissue is seen in the epidermis?
Keratinized stratified squamous
Why does the Stratum Granulosum appear so dark purple on a normal stain?
Because keratohyalin granules are basophillic
Where in the dermis are you likely to find a layer of loose areolar connective tissue?
Between the papillary layer and the epidermis
What is the thickest layer of the non-keratinized portion of the epidermis?
Stratum Granulosum
(These cells produce karatin precursors to the layers above them)
What do sebaceous glands secrete?
Sebum
Which layer of the skin thickens with pressure to form corns and calluses?
The Stratum Spinosum
What do myoepithelial cells do?
Squeeze sweat glands to release the sweat product
Where might the dermal epidermal junction be more “zippered?”
Areas of increased mechanical stress
What nail cell divides to form the majority of the nail?
Nail Matrix stem cells
Where is the water barrier of the epidermis primarily found?
Between the cells of the Stratum Granulosum and the Stratum Corneum
(It also exists between the layers of the Stratum Corneum)
What binds the apical sides of the keratinocytes of the Stratum Basale?
Desmosomes
In what layer of the eipdermis would we find “squames?”
Stratum Corneum
(This is what some people refer to the flat corneal cells as)
Where would the Stratum Lucidum be present?
Palms and Soles of the Feet
Where does melanin sit in the nucleus of a keratinocyte?
As a “dark umbrella” over the nucleus
(How is Dark Umbrella not the name of a goth rock band?)
What are Langer’s Lines?
Where are they found?
Regular lines of bundled collagen fibers as a response to the direction of stress
Found in the reticular layer of the dermis