Intro & Anatomy Flashcards
what are the the g_eneral, major functions_ of the skin?
- serves as physical barrier - against water loss & mechanical/chemical insults
- immunological control - prevents infection, inflammation & cancer
- temperature regulation
- protection from radiation
atopic dermatitis arises from disruption of what major skin function?
barrier dysfunction
prevents water loss & mechanical/chemical insults
molluscum contagiosum arises from disruption of what major skin function
immunological dysfunction
(prevents infection, inflammation, allergy, cancer)
disruption of the “temperature regulation” function of the skin can lead to…?
hyper or hypothermia
what is Reynaud’s syndrome?
what is due to?
chronic episodic attacks of digital ischemia provoked by cold exposure
d/t disruption of the temperature regulation function of skin
what skin component facilitates the “protection from radiation” function of the skin?
melanin
what are the layers of the skin & what does each consist primarily of?
- epidermis: primarily of keratinocytes
- dermis: primary of fibroblasts / collagen / elastic fibers
- subcutis (panniculus / hypodermis): adipose
where on the body is epidermis the
- thinnest?
- thickest?
- thinnest - eyelid
- thickest - palms & soles
what are the layers of the skin from superficial to deep?
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum germinativum (stratum basal)
the stratum basal (germinivatum)
- has what major function (s)?
- is composed of what major cell types?
- is organized how?
- major function: source of epidermal stem cells - i.e., dividing keratinocytes that migrate upwards to replace keratinocytes in other layers
- cell types:
- dividing keratinocytes (90%)
- melanocytes
- merkel cells
- organization: tonofibrils connect the cells to the basement membrane (BMZ)
the stratum spinosum
- has what major function (s)?
- is composed of what major cell types?
- is organized how?
i.e., the “prickle cell layer”
- major function: immune function, serves as supportive mesh
- cell types
- keratinocytes
- Langerhans cells
- organization: polyhedral shape (“mesh like network”) d/t desmosomes joining basal cells from stratum basal
stratum granulosum
- has what major function(s)?
- is composed of what major cell types?
- is organized how?
- major function: production of water-trapping barrier via secretion of lipids into ECF
- cell types: keratohyalin granule containing keratinocytes
- structure: cells are
- flattened
- anucleated
stratum cornuem
- has what major function(s)?
- is composed of what major cell types?
- is organized how?
- major function: keratinocyte desquamation - “end result of keratinization”
- cell types: keratinocytes
- structure: keratinocytes surrounded by lipid mixture (from stratum granulosum) - “brick and mortar”
- keratinocytes are
- flattened
- overlapping
- filled with: keratin + filaggrin
- keratinocytes are
where is the stratum corneum the thickest?
on the palms & soles
what epidermal layer contains melanocytes?
the stratum basale (germinivatum)
what epidermal layer contains merkel cells?
the stratum basale (germinivatum)
what epidermal cells contain keratohyalin granules?
the stratum granulosum (within keratinocyte cytoplasm)
what epidermal layer contains langerhans cells?
the stratum spinosum
what epidermal layer contains dividing keratinocytes?
the stratum basale (germivatum)
in which epidermal layer does desquamation occur?
the stratum corneum
which epidermal layer produces the lipids?
which epidermal layer is filled with these lipids?
- stratum granulosum - produces lipids
- stratum corneum - made of flattened keratinocytes surrounded by lipids
which epidermal layer contains filaggrin?
the stratum corneum - found in the cytoplasm of keratinocytes
keritinocytes in the stratum corneum are filled with..?
- keratin
- filaggrin
briefly describe the organization of each epidermal layer?
- corneum: overlapping, flattened, keratin & filaggrin filled keratinocytes surrounded by lipids
- granulosum: flattened, anucleated keratinocytes w/ keratohyalin granules
- spinosum: in polyhedral shape (“mesh like”) maintained by desmosomes
- basale: attached to basement membrane (BMZ) by desmosomes
in which epidermal layer do keratinocytes become flattened & anucleate?
the stratum granulosum
which epidermal layer is shown here and how do you know?
stratum spinosum
has “spiny” appearance d/t desmosome junctions holding keratinocytes in mesh-like form
in what “direction” through the epidermis do basal cells move?
from deep to superficial: basal → spinosum → granulosum → corneum
the increased thickness of the epidermis at the soles & palms is mostly due to what layer?
the stratum corneum
melanocytes are
- are found in which skin layer & and with what prevalence?
- have what role?
- are associated with what skin conditions?
- stratum basal
- 1:10 ratio of melanocytes: keratinocytes
- role:
- contain melanosomes that produce pigment in response to sun exposure that is
- delivered to stratum spinosum via dendrites
- protects against UV damage
- contain melanosomes that produce pigment in response to sun exposure that is
- associated with:
- vitiligo: destruction of melanocytes
- albinism: defective enzymes w/ in melanocytes (but normal melanocyte #)
Langerhans cells
- are found in what skin layer?
- have what role?
- are associated with what skin conditions?
- stratum spinosum
- role induce delayed type (type IV) hypersensitivity recognizing, uptaking & presenting antigens to sensitized T-cells
- associated with: contact dermatitis - - commonly triggered by poison oak
identify the features in the slide
bierbeck granules
langerhans cells (in stratum spinosum)
filaggrin
- is found in what skin layer?
- has what role?
- is associated with what skin conditions?
- stratum granulosum (in keratinocytes_
- role: retains water w/in keratinocytes
- associated with: atopic dermatitis - filaggrin mutation can can lead to asthma, ect.
merkel cells
- are found in what skin layer?
- have what role?
- are associated with what skin conditions?
- stratum basal, as well as
- oral mucosa
- hair follicles
- role: serves as a rudimentary touch receptor
- associated with: merkel cell carcinoma
from which tissue are merkel cells derived?
what unique features do they have?
- derived from neural crest cells / ectoderm
- contain a perinuclear dot
- stained with CK20
what are the major disease associated with epidermal dysfunction?
- bullous phemphigoid
- psorasis
bullous pemphigoid
- cause?
- presentation?
epidermal dysfunction
- cause: autoimmune - Abs against basement membrane (just below basal layer), causing fluid build-up between epidermis & dermis
- presentation: urticaria (red, itchy) precedes a tense bullae on an erythematous base
psorasis
- cause
- presentation
epidermal dysfunction
- cause - inc rate of epidermal turnover (thickening)
- presentation - scales
vitilgo - destruction of melanocytes
albinism - normal # of melanocytes but defective enzymes
contact dermatitis - mediated by langerhans cells
bullous pemphigoid - epidermal dysfunction: (autoimmune). tense bullae on erythematous base
psorasis - epidermal dysfunction: inc turnover of cells. scaly appearance
what are rete ridges and their importance?
are ridges that form junctions between the epidermis & dermis
the dermis is divided into what two major sections?
- papillary
- reticular
what are the key components that comprise the dermis?
- cells
- fibroblasts
- mast cells
- macrophages
- dendrites
- ECM
- collagen
- elastic fibers
- ground substance
- vasculature
- adnexal structures - sebaceous, eccrine & apocrine glands
- meissner’s corpuscles
what are the major cells types that comprise the dermis?
- fibroblasts
- mast cells
- macrophages
- dendritic cells
why is the role of fibroblasts and why is it important?
produces collagen (CT).
this is key in skin wound healing & scarring
which skin cells are most instrumental in wound healing?
- fibroblasts
- mast cells
dermal cell
what are keloids & what are they caused by?
- are abnormal scars
- made by uncontrolled synthesis/excessive deposition of collagen at sites of prior injury by fibroblasts
describe & compare the vasculature found in the dermis
- arteries: made of 3 layers
- tunica intima - endothelial cell layer
- tunica media - 2+ muscle cell layers
- tunica adventitia
- veins:
- thinner
- NO smooth muscle
- NO internal elastic membrane
dermal artery
what are the adnexae of the dermis?
- hair follicles
- sebaceous glands
- eccrine glands
- apocrine glands
sebaceous glands
- are found where?
- serve what purpose?
- note other characteristics.
- found everywhere except palms & soles
- most often found in association with other hair follicles
sebaceous glands are found in associated with hair follicles with the exception of which locations?
- nipple: montgomery’s tubercle
- penis/labia - tyson’s
- vermillion border of lips - fordyce granules
- eyelid: meibomian gland
eccrine glands
- are found where?
- serve what purpose?
- note other characteristics.
- found throughout the body
- purpose: regulate body temperature by excreting sweat onto
- are NOT associated with hair follicles
apocrine glands
- are found where?
- serve what purpose?
- note other characteristics.
- found only in a few areas:
- anogenital region
- external ear canal
- eyelid
- breast
- purpose: scent glands
- become functional at puberty
loss of which dermal gland can lead to hyperthermia?
eccrine (produces sweat)
which dermal glands are usually associated with a hair follicle?
sebaceous glands
meissner’s corpuscles
- what are they?
- where are they located?
- what is their role?
- special nerve end organs
- located in the dermal papillae: papillary section of dermis
- role: mediate sense of touch
subcutis layer
- has what major function(s)?
- is composed of what major cell types / components ?
- function: serves as a fat layer that insulates the body by separating skin from underlying fascia/muscles
- components:
- adipocytes (major)
- vater-pacrini corpuscles
identify picture, note important features.
adipocytes - are a singlet ring cell: one large lipid droplet with eccentrically located nucleus
found in subcutis
adipocytes - are a singlet ring cell: one large lipid droplet with eccentrically located nucleus
found in subcutis
erythema nodosum
- cause?
- presentation?
- inflammation of the subcutis (i.e., panniculitis) in response to infection, autoimmune dz, meds
- presentation:
- deep seated erythematous nodules - m/c on the shin
what are the two types of special nerve end-organs and their
- location?
- role?
- meissner corpuscle:
- in dermal papillae
- mediate sense of touch
- vater-pacini corpuscles
- in subcutis
- mediate sense of pressure
which type of immunity does each type of lymphocyte mediate?
- B-cell: humoral
- T-cell: cell mediated
- NK: innate
identify cell
lymphocytes
identify cell
mast cell -“fried egg appearance”
identify cell
neutrophil - multilobed
identify cell
plasma cell - pink cytoplasm, bilobed
identify cell
plasma cell - pink cytoplasm, bilobed
identify cell
plasma cell - eccentric nucleus with clock phase
mast cells
- contents
- role
- associated with what skin disorder(s)?
- contents:
- histamine
- heparin
- leukotrienes
- carboxypeptidase / tryptase
- role: mediates immediate type hypersensitivity reactions
- associated with: urticaria (type of wheel) - d/t vascular reaction
neutrophils
- contents
- role
- associated with what skin disorder(s)?
role: mediating acute infections
eisonophil
- contents
- role
- associated with what skin disorder(s)?
- contents
- major basic protein
- cationic protein
- catalase
- role: allergies, parasites
urticaria
- cause
- presentation
- cause: mast cell degranulation (immediate type hypersensitivity) that leads to vascular reaction
- presentation: wheel
what is the pilosebaceous unit and its components?
pilosebaceous = hair/oil unit
- hair follicle
- two glands: sebaceous + apocrine
- erector pili muscle
label the picture
- yellow - hair follicle
- blue - sebaceous glands
- red - epidermis
- green - dermis
define the following components of the hair follicle:
- isthmus
- infundibulum
- infundibulum: length of hair follicle from epidermis to sebaceous gland insertion
- isthmus: length of hair follicle from sebaceous gland insertion to arrector pili muscle insertion
outline the growth phases of the hair cycle
- anagen: active growth (2-6 years)
- catagen: regression (2-3 weeks)
- telogen: resting phase (3 months)
acne vulgaris
- definition
- causes
- definition: disorder of pilosebaceous unit
- causes:
- hair follicle plugging
- sebaceous gland activity
- p. acnes bacteria
- androgens
- from what is melanin produced? how?
- what is melanin’s role?
- produced from tyrosine by enzyme tyrosinase → pheomelanin or eumelanin
- UV protection
- delivered w/in melanosomes to basal cells, then absorbs UV radiation via free-radical scavengers
list each type of collagen and where it is found.
- type I & III - dermis
- type I - reticular dermis
- type III - papillary dermis
- type IV & VII - basement membrane
- type VIII - endothelial cells
