Panopto 26 Intugement Flashcards
name the 4 cells of the epidermis
- keratinocytes
- Melanocytes
- langerhans
- merkel
What cell in the epidermis is the most numerous?
keratinocytes
cytomorphosis
changes in cells anatomy due to changes in cellular activity
What’s another name for lamellar bodies?
Obland bodies, membrane coating granules
When are lamellar bodies formed?
at the same time as keratohyalin granules are forming as well as in the same cells
How big are lamellar bodies?
small (0.1-0.5um)
are lamellar bodies membrane bound or non-membrane-bound?
they are membrane bound, meaning they’re secretory
What do the granules in lamellar bodies contain?
lamellae or thin layers of a variety of lipids. they secrete the lamellae into the intercellular space, forming consecutive layers on the outer surface of the cell membrane (at least 2 layers)
What else other than lamellae do lamellar bodies contain?
enzymes (breakdown of desmosomes and serine protease)
is involucrin above or below the cell membrane
above
what kind of cells are in the stratum basale?
basal cells that are actively dividing and theres an abundance of free ribosomes in the cell making protein cytokeratin
How big is a tonofilament?
10nm
what are tonofilaments made of?
cytokeratin
as basal cells divide, where do they move to and from
move from the basement membrane and to the papillae
does cytokeratin carry over to the stratum spinosum?
yes
What are bundles of tonofilaments called?
tonofibrils
What are tonofibrils bound together by?
Filaggrin, the cytokeratin binding protein
What do tonofilaments and tonofibrils do?
They insert into desmosomes (bind cells together) and hemidesmosomes (bind the epidermis to the dermis by the way of the basement membrane). Multiple attachments (desmosomes and hemidesmosomes) counter the effect of friction on our skin
are cells more acidophilic in the stratum basale or stratum spinosum
stratum spinosum due to the increasing amount of cytokeratin
what does the stratum granulosum shift from?
the synthesis of cytokeratin to keratohyalin and lamellar bodies
what color are keratohyalin granules? what causes it?
dark blue due to negative charges of phosphates and RNA
how big are keratohyaline granules
1-5 micrometers (um) at their largest its the size of a RBC
Are keratohyaline granules membrane bound?
non membrane bound meaning the don’t leave the cell and are not secretory
composition of keratohyalin granules
filaggrin, phosphate, rich proteins, RNA
what are these keratohyalin granules known for being like
a black hole. They are reactive with surrounding tonofilaments and tonofibrils (they get sucked into these granules) incorporating cytokeratin filaments
what + what=eleiden
keratohyalin + cytokeratin
in the stratum lucidum is there keratohyalin or basophilia, what happens to the cytoplasm
no keratohyalin or basophilia the cytoplasm is more transparent and acidophilic
at what layer of the epidermis is keratin formed
stratum corneum
what two proteins are deposited on the surface of the cell membrane in the stratum granulosum?
loricrin and involucrin 2 insoluble proteins on the intercellular surface of the cell membrane
What does the physical barrier in the cell membrane do?
separates the internal (living cells in a watery environment) from the external (dry, surrounded by dead cells from the stratum lucidum and stratum corneum)
What enhances the water resistance of the physical barrier?
adding insoluble proteins on the inside of cells and adding layers of lipid on the outside of cells, which enhances the water resistance of this barrier
Where is the inactive enzyme serine protease found?
in the space between the cells in the stratum granulosum
why is serine protease inactive?
the ph of the Stratum Granulosum is neutral; as the cells move more into the stratum lucidum and then the stratum corneum, the ph gradually falls once it hits 4.5, which is the surface of the stratum corneum, where the enzyme activates
what is the target of serine protease?
desmosomal proteins, this allows for the dead skin cells to separate from the stratum corneum and then epidermis maintains the same thickness . Balances the new cells in the stratum basale with the loss of cells from the corneum.
