SKIN histology Flashcards
epiderm?
ECTODERM
dermis
MESODERM
basal layer of skin - deepeest
melanocytes, merkel, keritocinocytes
stratum spinosum
keritocytes, langerhaus macrophages
granulosum
kertinocytes
corneum
cornified - “terminally differentiated” - DEAD?
basale
deepest layer - attachment to basement membrane via hemidesmosomes
attached to one another desmosomes
hemidesmosomes
attach to basement membrane
basale - intense mitotic activity
move to spinosum
Maphighina layer?
spinosa and basale layers
both layers can mitose
invaginated during embyonic development - form glands - acinus
hair follicles, nails, appendages
invaginate?
what does this mean?
basale, large nucleus, keratin 5, 14
housekeeping cells - RER - crated keratin 5 and 14
melanosomes - membrane bound - trasnsported from melanocytes
basale, large nucleus, keratin 5, 14 - cytokeratines produced by basal cells - if mutations - epidermolysis bullosa cimplex complex
vs. keratin 1 and 10 - mutations - epidermolytic hyperkeratosis EHK
keratin 2e, 9
mutations? ichthyosis bullosa of seimens -
Or EPPk re Kerative 9
housekeeping cells - RER - crated keratin 5 and 14
melanosomes - membrane bound - trasnsported from melanocytes
melanocytes have dendrites
melanin
apoptosis occurs ?
when pass thru strat granulosa -
but things are still in the cell, foming epidermial barriers
15 - 30 days - stem cells can increase number by ?
hyperplasiogenic agents, or conditions like wounding, carcinogens, etc
change rate of proliferation
autoimmune disorders?
psyoiasis, carcinoma - degrees of distrubance - effects rate of proliferation
psoriasis - immune inflammatory
persistent hyperplasia of epidermis -
increase invagiations, papilla, take 3 - 5 days, instead of 28 - 30,
abnormal angiogenesis in dermis - blood vessels dilated, convoluted
causes inflammation - in epidermis and dermis - Th17 cells
Th17 - secrete IL 17 A - mast also secrete
Plaque
micro-absess
induce proliferation of different kerotinocytes -
creates abnormal epidermal plaque
thickening of stratum corneum
micro-absess
migration of neutrophils
spinosum - several shapes of cells
migration from basale - see cuboidal, plygonal, slightly flattened
name for spine like appearance re abundant desmosomes - so many connections
keratin process?
Keratin 1 - 10 in spinosum
someimtes basophilic, depends on what type of keratin -
lysosomal system abundant here in this layer of epidemis
phagocytic capacity high - may expalin why no scavagner cell system
keratinocttes after injury?
can engulf debris - like fibrin
spinosum, also see other organelles?
lamellar granules - (type 2 alveoli see also) here, have neutral sugars, lipids,
these are synthesized in spinous cells
store lipids
once in granular layer - released, form cell envelope
3 types of granules in granular leve
highly basophilic, can see granules - beyond lamellar granules - also see KERATOhyalinand TRICHOhyalin granules - not surrounded by membrane contain histidine proteins and cytine containing proteins
THIS why called stratum GRANULOSU, - because so many types of granules -
3 types
lamellar granules, increase in granulosum
site of action?
interface between granular and cornified cells
lipids remodelled
form LIPID ENVELOPE
exocytosis - form sheets -
also see cytopalamic organzesse with active synthetic metabolism
lamellar granules, increase in granulosum
site of action?
interface between granular and cornified cells
lipids remodelled
form LIPID ENVELOPE
exocytosis - form sheets -
also see cytopalamic organelles with active synthetic metabolism
stratum granulosum
involucrin
loricrin - 80%
cell envelope-
lipid envelope -
filagrin binding
keratin -
permeability barrier
1 multi lamellar lipids
linked to proteins - involuctrin, loricrin, etc
2 cornified envelope
3 keratin filaggrin complex
4 tight junctions w CLAUDIN 1, 4
transition from granular to cornified - programmed destruction of cell going on
live to dead cell -
but proteins - keratins, lipids, cell envelopes - are present -
viable to non-viable cell transition
during process?
loss of nucleus, cell organells,
DNase, RNase, hydrolases and proteeases activiate apoptosis
corneum?
flattened, 15 - 20 layers flattened non-nucleated keratinized cells = cytoplams filled with keratin
on see stratified squamous keratinized
on corneum layer
no nucles but?
demosomes and attached keratin are seen - system of baraces which trasnmit force
THICK skin 5th layer -
statum lucidum -
refractile eosinophilic cells on deep surface -
wavy clear stripe, above stratum granulosum
no nucleus, keratinization apoptosis advanced, no organelles
clear cells
is SECOND layer under corneum
dermo epidermal junction?
Basement Membrane Zone
Basement Membrane zone BMZ - separates epidermis from dermis
numerous genetic diseases at this levelo
immunie complexes are commeonly deposited, collage 4, 7, fibronectin, fibronin
see anchoring filaments, lamina lucida, lamina dense
dermal fibroblasts
intermediate filaments
hemidesmosomes -
collagen 4 - basement membrane
structural support and flexibility
anchoring fibrils - collagen type 7 = barrier/filter type 4
type 7 is ? adhesion ? to epidermal cells? linking protein
disorders with basement membrane?
blister formation -
bullous pemphigoid - antibody against specific antigentBPAG
epidermolysis bullosa - COLLAGE 7 (linking protein)
keratin genee mutation - affecting connection of tonofibrils to hemidesmosomes
nonkeratining cells of epidermis?
langerhand 5% - spinosa
melanocytes and merkel - basale
melano5 - 10%, erkel 1%
melanocytes - Neural crest
melanocytes neural crest - and Merkel cells
color red, yellow, brown, blue - four skin pigments -
not attached Free Agents - to adjacent keratinocyte by desmosomes
cell processes of melanocytes?
facilitate transportation of melanin
color of skin - produced here
exogenously - carotenoids (yellow)
endogenously melanin (brown)
oxygenoated hemoglobin - red
reduced hemoglobin - blue -
Melanosomes - store melonin
tyrosina converted to 3, 4 DOPA
into dopaquinone into melanin -
melanosoes
brown or black eumelanin- eliptical
red / yellow less regular shape
black skin?
larger melanosomes than more lightly pigmented skins
dendrites carry melanin?
thru microtubular process! transport melanin into tip of dendrites of melanocytes
f actin involved - whole journey involved
rab 27a, f acin, disassociate - exocytosis to keritinocytes
mutations of myosin VA
ALBINISM Myosin Va
Griscelli syndrome - white hair can’t trasnport
can’t transport, cant exocytose
ALBINO
sometimes mutation of RAP 27a or melnophilin genes
microphtthamia associated trasnpcription factor MITF - binds to
cAMP, CREB, MITF ERK pathway
lack of functional MITF producdes albinism or premature greying -
excessive MITF occurs?
melanoma
Melanocytes?
dendrite role?
melanocytes- melanosomes transfer pigment - progects skin by absorbing, scattering postential harmful radiation from son UBB< UBA
melanosomes - in apical region - blocks UVB, UVA
within keratinocytes - degraded by lysosomal ?
lack of corticol from adrenal ?
Addison’s disease
albinism
absense of tyrosinase enzyme
skin not protected from solar radiation by melanin - greater incidence of basal and squamous cell carcinomas
vitiligo?
auto immune destruction of melanocytes
moles or NEVI
benign accumllations of melanocytes in dermis -
junctional nevus
compound nevus
malignant melanoma -
pale affected people more affected
merkel cells
tactile Info - found in glabrous skin of digits, lips and outer root of sheath of hair
nucleus lobulated
joined by desmosomes
organells - dense cor granules, nerve endings collecting opposite to golgi complex
merkel cells?
NEURAL crest or ectoderm
type 1 mechanoreceptors - pre and post synaptic modification of synaps
Lnagerhans cells
in spinous layer - immigrant cell -
they have dendrites like melanocyts
no junctions - free to move
indented nucleu,
no tonofilaments, no desmosomes
rod like racket includsoin BIRBECK”S granules - contain langerin protein and CD1a - to uptake antigens
come from mesenchyme, monoctye lineage
APCs and delayed type hypersenstivitiy eg contact allergic dermatitis
important in rejection of grafts
langerin, CD1
how they take in the antigens
langerhans leave epidermis, travel to regional lymph nodes
and present to T cells,
layers of thin skin from inside
basale, spinosum, granulosum, corneum
thick skin - - lucidum 4th layer
The epidermis consists of several layers beginning with the innermost (deepest) stratum basale (germinatum), followed by the stratum spinosum, stratum granulosum, stratum lucidum (when present), and ending with the outermost layer, the stratum corneum.
Epidermolysis Bullosa EB - Blistering diseases occur betwe?
epidermis and basement membrane
layer where epidermis cells are made and passed upward?
Basale - single layer
note blood vessels just below in papilla of dermis
melanocytes also in the single layer of cells
how the skin keeps out water?
corneum -
basale cells
produce new daughter cells that rise up
attached to basement membrane via hemidesmosomes
spinosum - as cells move up
connected to each other via desmosomes - so many - named spinosum - can see the desmosomes that look spiney -
attached to basale cells via DESMOSOMES
kerotinocytes making keratin
hey are metabolic active, making keratin, have their organells -
stratum granulosum?
can see granules of keratin
this is where they lose nucleus
why are dark people dark?
inefficient degradation of melanozomes
UV light comes from sun
Uva? does it penetrate dermis?
UVB
UVA - not stopped by dermis, gets past epidermis - causes ROS and apopotosis -
not blocked by glass
UVB - doesn’t get below dermis
affected epidermis
causes DNA damage -
CANCER
is blocked by glass
Pigment - is to protect cells from UV damage
basale and melanocytes - how protect skin from sun damage?
melanocytes - are stable, not supposed to replicate, but can. Replication leads to malignancy- proliferation and UV damage - makes malignancy risk possible
Purpose of pigment
provides shield for nuclei down at basement membrane-
upper cells - no nucleus to hurt
it’s the basal cells that become damaged - and proliferates - that’s the danger
however, removing pigment is a goal of coronocytes because trying to get rid of nucleus??
malphilian Layer?
epidermis? The Malpighian layer of the skin is generally defined as both the stratum basale and stratum spinosum as a unit, although it is occasionally defined as the stratum basale specifically,or the stratum spinosum specifically. It is named after Marcello Malpighi.
retic dermis - what type of collagen
Type 1
collagen = protein fibers
lots of fibroblasts - make elastic and collagen
dermatin sulphate made by?
fibroblasts
Langer lines?
longitudinal? what are they?
Dermis - scars during pregnancy
striae gravidarum - white streaks
elasticity of skin over time?
increases 5x from fetal to adult
old age - lose elastic, cross linking of collagen, degeneration - wrinkles
more sunlight accelerates
-
Ehlers danlos - collagen problem
defective fibrils - too elastic
marfans - elastin - fibrullin
makes elastic fibers -
fibrullin problem
hypodermis - not part of skin
fat cells - in abdomen - 3 cm or more can be
absent in eyelid, penis, scrotum,
contains hair follicles, sweat glands
blood supply?
in subcutaneous - hyperdremis
sweat glands, hair
dermis
arteriovenous anastomoses -
relaxation CONSERVES
Constriction - sends onward into arches - gets rid of heat
shunts - GLOMUS body (ascending arteriole)
RELAXATION - bypasses - CONSERVES HEAT
Lymphatics - in papillae
drains excess fluids
innervatin of skin
lack of hair - more sensory
free nerve endings - touch, pain, temp, itche - particularly dense in hairless - aredolae, labia, glans penis, lips
3 categ of sensory receptors
exteroceptors - external
proprioceptors - in muscles - tendons - about position, movement of body - M SPINDLES, golgi tendons
Interoceptors - internal organ info
sensory receptors of skin
1 mechanocepts - stetching, vibration - touch
MERKEL disk - basal epidermis - epidermal/dermal junction
Meissner corp - epiderma/dermal junction
in Papillary
Ruffini endings
Pacinian corpucles - flattenened circular cell - ONION cut
2 thermosceptors
3 nociceptors
Meissner touch corp
ovoid, long axis
Pacinian Lammellated corp - ONION structure
VIBRATION
circular
senstitive to movement, vibration, stetch, pressure
lamellated - onion structure
Thermosreceptors - temp
detect warm/cold - KRAUSE end bulb - detect cold - eye, mucosa of tongue, epineurium of nerve, clit/penis
nociceptors - pain stimulie
free nerve ending - from dermal nerve plexus - cutaneous branches of spinal nerves
skin surface
peritricial nerve ending - HAIR
very sensitive - pull out hair - just under subaceous glands
see chart- 7 kinds
seven different sense reepctors -
innervations
sweat gladnd, smooth mucles, arrector pili - sympathetic
HAIR - keratinized - epidermal area - move DOWN into dermis
malphigian layer - stratum spinous and basale move DOWN into dermis
where hair not found?
palms,
melanocytes, do they move down, up?
colors your hair
first hair - lanugo = wool
unmedulated, unpigmented, later shed - then get postnatal hair
vELLUS, unmedulated
Terminal medulated
cycle of hair growth -
anagen phase - growing
TELOGEN - resting phase
hair falls out or is pulled out
shed hair - club hair becasuse of shape of roof
new hair grows to replace old
some hair - 4 years
bulge stem cell - w root sheath - 3 areas supplied - epidermis basal subaceous hair follices
can migrate - into all sorts of places, and stimulate - into basal area, stratum spinosa, subaceous,
myosin VA - color - transports melanin into f-actin filaments
so if problem here - color is off
Nails -
keratizined plates - from invaginations of stratus basale and spinosa
eponychium -
onychodermal hand -
hyponychium
glands - subaceous, sweat, mammary (discussed next block)
sebaceous - goes with hair follicles -
sweat glands COILED - not associated with hair
sebaceous - not found where?
no hair - palms, soles, dorsa of feet
sebaceous - pilodebaceous unit absent in mucous membranes
on cutaneous surface - ?
hair free sebaceous glands are found in mucourse areas of
oral cavity, labia monor, tyson’s gland, eyelids
duct - stratified squamous epithium continuous with?
external root sheath of hair
located?
in dermis, each gland encapsulated by think CT
simple branched alveolo - sunthesize lipid
most glands - several alveoli open in to duct, whithc empiteis into neck of hair follice
basal cells of sebaceous - holocrine secretion - mechanism - cell DIES and disintegrates
WHOLE cell has to die to release Sebum
to release the lipids
8 days
arrector pili muscle helps out
secretion of sebum
fatty acids, cholesterol
natural lubricant to hair, prevents brittle hair, oils skin - prevents excessive evaporation from stratum corneum
also protects agasint excess surface water
bacterial
stiumulate by androgens - hormones
testosterone at puberty - their size and action increase -
women - estrogen depress activity (SKIN DRIES OUT - aging factor?)
thought in women - adrenal and ?
Holocrine mechanism?
whole cell has to die
Acne vulgaris
androgens - stimulate sebaceous gland - produce sebum, leads to follicular keratinzation and obstrution
propionibacterium acnes
propionibacterium - enter clogged pore and multiply
redness, inflamationand leading to papillary, pustulary and cystic acne
propionibacterium - enter clogged pore and multiply
redness, inflamationand leading to papillary, pustulary and cystic acne
blocks ? hair ?
agents for acne?
retinoids - vitamin A
drugs reduce size of sebaceous glands , recuce sebum produtcion and regulated cell proliferation and differntiation
sweat glands -
two types
ordinary and odor
coiled secretory portion -
deep in dermis, and straight excretory ducts/glands
ordinary sweat glands - eccrine - everywhere but?
skin of nipple, margins of lips
few on sweat glands,
LOTS on palms, soles, fingertips
SMALL size compared to other type
ordinary sweta gland - two types
clear and dark and
myoepithelia cells
secretions from ordinary cells
dark?
adjacent to lumen -
clear cells between dark and myoepit cells
dark - secretory granulses
clear cells - NO secretory granules - small amount of RER, numerous glycogen granules
clear cells have?
caniculi - secrete water and electrolytes and ?? from dark cells?
Secretory portion
These are either cuboidal or pyramidal in shape. The clear cells mainly produce electrolytes and water, whilst dark cells release the macromolecular substances found in sweat.
found deep in dermis
stratified cuboidal - duct are darker
eccrine glands produce?
watery solution - It is a excretory organ
cystic fibrosis - and your sweat glands
defect in CFTR
reduction of choloride secretion intoh airways of respiratory system also viscous mucus - immoobilizing neurtrophils
decrease in reabsorption of sodium and chloride - increase concentration of sweat - sweat salty
ordinary sweat - major role in cooling
postganglionic cholinergic - Ach - sympathetic
where does sweating being??
forehead - and down to rest of body
sweating also caused by emotional stimuli - palms, soles (lie detector tests.
Apocrine sweat glands
odoriferous sweat glands -
skin of axilla, nipples, scrotum, pubic region , perineal
ceruminous glands? glands of moll - external auditory meatus
larger than ordinary glands
ducts lined with cuboidal to columnar
convex apical borders
myeoepithelial cells - but not found in ducts
stress, sexy, etc cause secretions
secretions?
oilly, yellow, pilid amonia, protien
once reaching surface - odorless
not concerned with thermoregulation
function at puberty, under control of sex hormone - in females, axillary and ?
mode of secretion of glands?
merocrine - sweat glands - done by all sweat glands
Mode of merocrine
NORMAL exocytosis - no destructin of cell
apocrine secretion (mammary glands) pinching off
little destrcution
HOLOCRINE - whole cells dies
apocrine glands secrete via? Merecrine
modified apocrine sweat glands
At basale layer- what’s there?
basale cells (cuboidal) that are NOT keritanocytes
merkel cell (NEURAL crest - ectoderm)
Melanocytes (Neural crest - ectoderm)
What do melanocytes produce?
melanin pigment - gives color and protects from sun
Where are merkel cells found in abundance?
hands, feet, liips?
Fingerprints?
Where stratum basale meets the pappillae of underlying dermal layer- forms ridges
langerhan cells are from what germ layer??
ha! mesoderm, Lateral , splanchnic - BLOOD
epidermis germ cell layer? dermis cell layer?
epidermis - ECTODERM
Dermis - Paraxial MESODERM
Precursor of keratinocyte?
attached to dermis via?
basal cell
hemidesmosomes at the basement membrane
at basale layer - what 3 things found?
basal cells (that synth keratinocytes) that fill up all the layers above
melanocytes
merkel cells
Spinosum layer?
10 layers of keratinocytes, w/ langerhans
these cells begin the process of making keratin - and release GLYCOLIPIDS (waterproofing)
Stratum granulosum?
3 - 5 layers
cells flatter, thicker
Produce a LOT of keratin and keratohyalin which accumulate as LAMELLAR granules
as cells die - leave this behind to form corneum and hair and nails
Strat. Lucidum - transparent - found where? palms, soles, digits -
cells dead and flattened - packed with ELEIDEN - clear protein w/ lipids derived from keratohylain - giving it the clear appearcen - barrier to WATER
What do Keratohyalin granules do?
the main function of keratohyalin granules is to bind intermediate keratin filaments together. At the transition between this layer and the stratum corneum, cells secrete lamellar bodies (containing lipids and proteins) into the extracellular space.
Strat. Corneum -
15 - 30 layers -
removed every 4 weeks -
cosmetic procdueres microdermabrasion removes layers
Pappillary layer and Reticular layer of ?
Dermis
Papillary - loose CT - mesisner corpuslces
phagocytes, fibroblasts, fat, vasculature, nerfve, lymph capillaries
reticular - dense - irrgeulat
thicker, sensory vasculatirzed
elastin collagen, structure
Where is fat stored?
hypodermis
Melanosome?
vesicle transporting melanin into keratinocyte
Color of skin?
Melanocytes at basale layer create melanin- transfer into kertinocytes via melanosome -
The more sun, the more?
melanin manufactured - eventually lysosome eat or it it is sloughed off, so you Lose your Tan
too much melanin?
can interfere with production of Vitamin D - balance between vit d production (available sunlight and folate destruction) vs. protection from UV
What good thing does melanin do?
protects skin from UV radiation and break down of folic acid
Freckles? Moles
freckles - irregular accumulation of melanocytes
Moles? large masses - may indicate cancer
Albinism? Vitiligo?
inability to produce melanin
Vitiligo? certain parts of the body lose their ability to produce melanin - maybe auto immune reaction
How is melanin made?
melanosomes contain TYROsinase - which via DOPA turns into melanin
called a melanin granule when loses its tyrosinase - transferred to keratinocyte
Merkel cells - in basale layer -
NERVE Plates
they are in contact with sensory nerve fibers that project from dermis into epidermis - terminating in plate like endings -
Langerhans cells - what kind of allergic reactions?
Birbeck granules
Birbeck granules, also known as Birbeck bodies, are rod shaped or “tennis-racket” cytoplasmic organelles with a central linear density and a striated appearance. First described in 1961 (where they were simply termed “characteristic granules”), they are solely found in Langerhans cells.
Type IV
they phagocytose antigens here - leave epidermi, enter lymph where become DENDRITIC cell - exhibiting MHC I, and II, and B7 molecules - activating T cells
Meissner corpuscle vs Merkel cells
Merkel’s disks are densely distributed in the fingertips and lips. They are slow-adapting, unencapsulated nerve endings, and they respond to light touch. … Meissner’s corpuscles respond to touch and low-frequency vibration. Ruffini endings detect stretch, deformation within joints, and warmth.
epidermal - dermal junction?
attached to basment membrane via hemidesmosomes
Eccrine Sweat Glands - normal sweat glands
clear cells, dark cells
secretory portion - clear cells -
dark cells secrete via merecrine -
xocytosis from secretory cells into an epithelial-walled duct or ducts and then onto a bodily surface or into the lumen.
pores on skin - when open?
aldosterone stiumulates opening onto skin
what regulates body temperature?
sweating - sympathetic releases ACH - NE exception
Emotional sweating?
sympathetic vis NE
Emotional sweating occurs in response to emotive stimuli such as fear, stress, pain and anxiety. Although it can occur over the whole body surface, it is most evident on the palms, soles, underarms and forehead. In contrast to thermal sweating, emotional sweating occurs independent of ambient temperature.
Where is the cell envelope and lipid envelope found?
around and in side the keratinocytes - the lipid envelope are formed into sheets forming outer protective coating
also a thick layer of insoluble protein is deposited on inner surface of keratincyte cell’s plasma membrane called the cell envelop
What’s the epidermal melanin unit?
ratio of melanocyte to keratincyte in basal layer
same in all races -
degradation rate of lysosomes is what determines skin color
Pacinian corpucle? ONION like
sensory cell in deep thick of dermis / hypodermis
encapsulated tactile mechanoreceptors - embedded in deep dermis and hypodermi
Merkel cell base?
lost their myelin sheath when penetrating epidermal basement membrane - expand into disc or plate closely associated with base of merkel cell -
tactile mechanoreceptor -
NEURAL crest
Meissner corpuscle -
detect shape and texture - ellliptical - within cores of dermal papillae - long axis perpendiculat to surface of skin - “twisted skein of wool” do to spiral Schwann cell arrangement
Scheleroderma - excessive collagen in what layer of skin?
reticular dermis
lack of adequate blood supply also kills off nerve and sweat glands - face becomes masklike -
hair follicles? hair is all over the body - except for a few spots
Hair follicles are invagiations of epidermis extending from surface to dep reticular dermis and/or hypodermis -
responsible for continuous growth
base of hair bulb has a ?
dermal papilla - a tuft of vascularized loose CT
the dermal papilla contains a capillary network that nourishes and sustain the living hair follicle - disruption of blood flow results in death of hair follicle
external root sheath is a continuatin of epidermis that covers hair follicle
downgrowth of basal layer is called external root sheath
glassy membrane?
hair - basement membrane becomes thickened, dense CT form sheath,
hair matrix?
epithelial cells surrounding the dermal papillae -
matrix cells differentiatiate into hair keratin producing cells
What cell produces vit D?
keratinocytes when exposed to sunlight
vitiligo - auto immunity?
melanocytes die off
albinism?
Normal melanocyte number with LOWER melanin production due to LOWERED tyrosinase activity OR defective tyrosine transport. risk of skin cancer
peg and socket?
connections between epidermis and dermis in most of skin -
in THICK SKIN _ on fingertips - ridges and grooves -
immigrant cells of epidermis?
langerhans - mesoderm - lateral plate, splanchnic
merkel - neural crest - ectoderm
melanoctyes - neural crest
Keratinizataion?
genetically programmed series of events in POSTMITOTIC keratinocytes
- synthesis of proteins - eg kertain, keratohyaline) and lamellar granules
alterations affeting cell structure and organelles
cell envelope in corneum?
lipid layer outside (in sheets), inside the cells - proteins
lipids for lamellar bodies -
cell proliferation at basale layer - over production?
psoriasis, cancer
wound healing rate changes
psoriasis?
hyperplasia of epidermis - 3- 5 days instead of 28 - 30
abnormal angiogenesis at dermis capillary area
inflam cell inflictrate - activated Th17, neutrophils migrate here forming microabscesses PLAQUE
keratinocytes - can they phagocytose?
I don’t know, but they can after wounding enggul cellular debris
lamellar bodies? granuloseom layer - what’s happening
Fillafrin - FILLS IN - binds the protective cell envelope
filaggin - eventually produced from keratohyolin and trcholyalin (non membrane bound granules)
which BINDS aggregated to protect skin
Tyrosine, - melanin
an amino acid found in the body, plays its role in the skin by helping to produce melanin. … This hyperpigmentation is stimulated when an enzyme called tyrosinase signals the production of melanin, which happens in the skin’s melanocytes.
action level where cell envelope develops?
granulosum meets corneum
granules exocytosed
sheets of lipids
involucrin, Loricrin 80%?
proteins developed inside of cells - cell envelope
strat corneum
desmosome, atteched kertain filamantes form a bracing system to stabilize tissue
dermo epidermal junciton?
hemidesmosomes and anchoring filaments of basal membrane zone - BMZ - created by epidermis
from dermis - anchoricng fribrils extend into lamina dense and matric - formed by dermal fibroblasts
disorders at basal epidermal junction?
blisters -
bullous pemphigold - acts against hemidesmosomes
another blister problem happens between within cytoplasm of basal cells - separating them into two - (keratin gene mutation?)
melanocytes at basale layer - are they attached to keratinocytes?
can they still divide at epidermal layer?
No -
Yes - can still divide
skin color?
four pigments - producted in skin - melanin - others colors from blood, reduced blood and cartoenoids
melanosome?
roll and size?
size varies - typically black skin are larger
stores melanin - and this is where melanin created -
structure of melanosome varies depending upon type of pigment synthesized - brown/black elliptical
red yellow - less regular shpae
How melanin created?
series using TYROSINASE via DOPA
what happens to melanin?
transferred via melanosomes to keratinocytes -
melanin protects skin from UVB and UBA
how are melanosomes degrades in keratinocytes?
lysosomal enzypes
melanosomes in keratinocytes can lie singly or can form groups - supranulear region enclosed by a membrane
disorders of melanocytes??
Addisons - adrenal gland
Addisons - lack of cortisol from adrenal cortex - OVER production of hormone, increasing pigmentation
adrenal gland not working
albinisim
can’t synthesize melanin- absense of tyrosinase activity or disfunction
vitilago
autoimmunite - destroys melanocytes
Moles, malignant melanoma
melanocyte problems - moles/nevi often begign
nevis - at which skin level?
can be epidermis, dermis or combines (compound nevus)
are merkel cells found in hari?
mechanoreceptor type 1
Yes -
found in digits, lips and outer root sheath of hair
join keratinocytes with desmosomes
langerhands cell - what kind of hypersensitivyt?
S100
birbeck granules -
involved in uptake and delivery of antigens - tennis rackets
type IV - contact dermatitis
rejection of grafts -
protect against environmental antigen
sweat glands - temp reg - where too warm of blood is detected?
hypothalamus - sends message to sympathetic - cause sweat via AcH - forehead starts
vs emotional sweating - palms soles of feets - adrenergic NE - flight fight
how does sweat get out?
myoepithelia cells help - contracting “muscle” cells - MYO -
Aldosterone and salt preservation?
as sodium chorloride leaves via sweat in duct - aldosterone grabs the sodium choloride to preserve in hot climates
“increases reaborption”
are apocrine or eccrine sweat glands larger?
MERECRINE secretions
apocrine - only in armpits, nippis, scrotum, etc
TEN TIMES larger than eccrine
flight/fight, sec etc - myoepitheial cells innervated by nervous system - help squeeze it out
where does odor come from
odorless at surface - full of bacteria - starts to rot - decomposition
Hair
shaft vs. bulb
Hair is made of a tough protein called keratin. A hair follicle anchors each hair into the skin. The hair bulb forms the base of the hair follicle. In the hair bulb, living cells divide and grow to build the hair shaft
