Derm Histo Flashcards
What kind of epithelium lines the duct of eccrine sweat glands?
stratified cuboidal
Which layer of the epidermis secretes tonofilaments? In which layer do the tonofilaments become tonofibrils?
stratum basale, stratum spinosum
What do Pacinian corpusles detect? What makes up the inner core? Outer core?
vibratory pressure and mechanical stimuli? Inner = Schwann cells, Outer = endoneurium
What kind of cells make up the stratum germinativum?
columnar
How are the cells of the stratum spinsoum connected to one another? What effect does this have on their shape?
by desmosomes? It gives them a spiny look when the cells shrink for histo prep since the connections remain but the cell shrinks
What causes thermoregulatory sweating? Emotional sweating?
cholinergic and adrenergic stimulation of eccrine glands, respectively
Which layer of the epidermis contains high levels of keratohyalin granules?
Stratum granulosum
What are “Langer’s lines”?
They are lines of tension formed via the Type I collagen and elastin present in the reticular dermal layer
Where will you find melanocytes?
stratum basale
What is pigment donation?
When the tips of the melanocytes containing melanin are phagocytosed by keratinocytes
What epithelium lines the duct of apocrine sweat glands?
stratified cuboidal
Which structures are responsible for fingerprints?
dermal papillae
What structures are notable for forming the lipid envelope of skin cells?
lamellar bodies secreted to the outside of the cell
What gives the stratum granulosum its basophilic color?
keratohyaline granules
T/F: the epidermis is vascularized
false that is the point of the dermal papillae, they extend up to the abutting epidermis and from there nutrients travel via diffusion
T/F: nuclei are present in the stratum lucidum of thin skin but not thick skin
false, first of all the stratum lucidum is only ever present in thick skin, second there are no nuclei in the stratum lucidum = the cells are dead
Which sweat glands are located “everywhere”? Where are they not located?
eccrine (merocrine secretion); rubor labii and external genitalia
Mechanism of secretion of sebaceous glands
holocrine
Melanin production is increased by what hormone? What parent molecule does this come from?
MSH, comes from POMC so associated with ACTH? recall this is why there is hyperpigmentation in Addison’s dz
What are the “spines” in the stratum spinosum?
Desmosomes
what is the name of the edge of skin covering the nail root?
eponychium
Where will you find the matrix cells of the hair follicle?
around the dermal papilla
What collagen fibers make up the dermal papillae? What sensory nerve endings might you find in here? Myelinated or unmyelinated?
Type I and II; Meissner’s corpuscles, myelinated? the only unmyelinated ones are C fibers
What are the 3 cell types of the secretory segment of an eccrine sweat gland?
clear cells to secrete the watery component, dark cells to secrete protein, and myoepithelial cells to push it all along
What connects the epidermis to the dermis?
hemidesmosomes
what connects the epidermis to the dermis? What connects the cells of the stratum spinosum to one another?
hemidesmosomes, desmosomes
What do Merkel cells detect? Myelinated or unmyelinated?
pressure? Myelinated the only ones not myelinated are C fibers
Where will you find Merkel Cells?
in the stratum basale
Langerhans cells come from what parent cell (ultimately)?
CD34 pluripotent hematopoietic stem cell
What layer of the nail is the formative layer?
nail matrix
How can you differentiate a Langerhans cell from a melanocyte?
Melanocytes are located in the stratum basale and Langerhans cells are located in the stratum spinosum
How are Langerhans cells connected to the keratinocytes?
They arent
Name 2 modified sebaceous glands
Glands of Moll on the eyelid and Ceruminous glands (wax) of ear canal
What is contained in the invagination of the inferior segment of the hair follicle? Why is it important?
dermal papillae, this provides nutrients to the growing hair
Where will you find Meissner’s corpuscles?
IN THE DERMAL PAPILLAE
Which layer is the skin-nail junction?
hyponychium
Where is the melanin in a melanocyte contained?
melanosomes
If you were to poke a hole in the skin, why would it be elliptical rather than round?
The Langer’s lines in the reticular layer of the dermis form lines of tension
How are the melanocytes attached to keratinocytes?
They arent, the migrated in from neural crest and just kind of chill there
What kind of muscle makes up the arrector pili muscles?
smooth muscle
How is the lumen of apocrine and eccrine glands different?
lumen of apocrine are wider
What are the 3 layers of the internal root sheath?
outer Henles layer of cuboidal cells, then huxley’s layer which is 1-2 layers of squamous cells, on the inside is the cuticle of the hair shaft
What 2 keratohyalin granules are present in the stratum granulosum?
trichohyalin and filaggrin
