Intro & Anatomy Flashcards
1
Q
what are the the g_eneral, major functions_ of the skin?
A
- serves as physical barrier - against water loss & mechanical/chemical insults
- immunological control - prevents infection, inflammation & cancer
- temperature regulation
- protection from radiation
2
Q
atopic dermatitis arises from disruption of what major skin function?
A
barrier dysfunction
prevents water loss & mechanical/chemical insults
3
Q
molluscum contagiosum arises from disruption of what major skin function
A
immunological dysfunction
(prevents infection, inflammation, allergy, cancer)
4
Q
disruption of the “temperature regulation” function of the skin can lead to…?
A
hyper or hypothermia
5
Q
what is Reynaud’s syndrome?
what is due to?
A
chronic episodic attacks of digital ischemia provoked by cold exposure
d/t disruption of the temperature regulation function of skin
6
Q
what skin component facilitates the “protection from radiation” function of the skin?
A
melanin
7
Q
what are the layers of the skin & what does each consist primarily of?
A
- epidermis: primarily of keratinocytes
- dermis: primary of fibroblasts / collagen / elastic fibers
- subcutis (panniculus / hypodermis): adipose
8
Q
where on the body is epidermis the
- thinnest?
- thickest?
A
- thinnest - eyelid
- thickest - palms & soles
9
Q
what are the layers of the skin from superficial to deep?
A
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum germinativum (stratum basal)
10
Q
the stratum basal (germinivatum)
- has what major function (s)?
- is composed of what major cell types?
- is organized how?
A
- 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)
11
Q
the stratum spinosum
- has what major function (s)?
- is composed of what major cell types?
- is organized how?
A
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
12
Q
stratum granulosum
- has what major function(s)?
- is composed of what major cell types?
- is organized how?
A
- major function: production of water-trapping barrier via secretion of lipids into ECF
- cell types: keratohyalin granule containing keratinocytes
- structure: cells are
- flattened
- anucleated
13
Q
stratum cornuem
- has what major function(s)?
- is composed of what major cell types?
- is organized how?
A
- 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
14
Q
where is the stratum corneum the thickest?
A
on the palms & soles
15
Q
what epidermal layer contains melanocytes?
A
the stratum basale (germinivatum)
16
Q
what epidermal layer contains merkel cells?
A
the stratum basale (germinivatum)
17
Q
what epidermal cells contain keratohyalin granules?
A
the stratum granulosum (within keratinocyte cytoplasm)
18
Q
what epidermal layer contains langerhans cells?
A
the stratum spinosum
19
Q
what epidermal layer contains dividing keratinocytes?
A
the stratum basale (germivatum)
20
Q
in which epidermal layer does desquamation occur?
A
the stratum corneum
21
Q
which epidermal layer produces the lipids?
which epidermal layer is filled with these lipids?
A
- stratum granulosum - produces lipids
- stratum corneum - made of flattened keratinocytes surrounded by lipids
22
Q
which epidermal layer contains filaggrin?
A
the stratum corneum - found in the cytoplasm of keratinocytes
23
Q
keritinocytes in the stratum corneum are filled with..?
A
- keratin
- filaggrin
24
Q
briefly describe the organization of each epidermal layer?
A
- 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
25
in which epidermal layer do keratinocytes become flattened & anucleate?
the stratum granulosum
26
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
27
in what “direction” through the epidermis do basal cells move?
from deep to superficial: basal → spinosum → granulosum → corneum
28
the increased thickness of the epidermis at the soles & palms is mostly due to what layer?
the stratum corneum
29
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
* associated with:
* **vitiligo**: destruction of melanocytes
* **albinism:** defective enzymes w/ in melanocytes (but normal melanocyte #)
30
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
31
identify the features in the slide
bierbeck granules
langerhans cells (in stratum spinosum)
32
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.
33
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
34
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
35
what are the major disease associated with epidermal dysfunction?
* bullous phemphigoid
* psorasis
36
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**
37
psorasis
* cause
* presentation
epidermal dysfunction
* cause - **inc rate of epidermal turnover (thickening)**
* presentation - **scales**
38
vitilgo - destruction of melanocytes
39
albinism - normal # of melanocytes but defective enzymes
40
contact dermatitis - mediated by langerhans cells
41
bullous pemphigoid - epidermal dysfunction: (autoimmune). tense bullae on erythematous base
42
psorasis - epidermal dysfunction: inc turnover of cells. scaly appearance
43
what are rete ridges and their importance?
are ridges that form junctions between the epidermis & dermis
44
the dermis is divided into what two major sections?
* papillary
* reticular
45
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
46
what are the major cells types that comprise the dermis?
* fibroblasts
* mast cells
* macrophages
* dendritic cells
47
why is the role of fibroblasts and why is it important?
produces collagen (CT).
this is key in skin wound healing & scarring
48
which skin cells are most instrumental in _wound healing_?
* fibroblasts
* mast cells
dermal cell
49
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
50
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
51
dermal artery
52
what are the adnexae of the dermis?
* hair follicles
* sebaceous glands
* eccrine glands
* apocrine glands
53
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
54
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
55
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
56
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
57
loss of which dermal gland can lead to hyperthermia?
eccrine (produces sweat)
58
which dermal glands are usually associated with a hair follicle?
sebaceous glands
59
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
60
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
61
identify picture, note important features.
**adipocytes** - are a _singlet ring cell:_ one large lipid droplet with eccentrically located nucleus
found in subcutis
62
**adipocytes** - are a _singlet ring cell:_ one large lipid droplet with eccentrically located nucleus
found in subcutis
63
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_
64
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
65
which type of immunity does each type of lymphocyte mediate?
* B-cell: humoral
* T-cell: cell mediated
* NK: innate
66
identify cell
lymphocytes
67
identify cell
mast cell -"fried egg appearance"
68
identify cell
neutrophil - multilobed
69
identify cell
plasma cell - pink cytoplasm, bilobed
70
identify cell
plasma cell - pink cytoplasm, bilobed
71
identify cell
plasma cell - eccentric nucleus with clock phase
72
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**
73
neutrophils
* contents
* role
* associated with what skin disorder(s)?
role: **mediating acute infections**
74
eisonophil
* contents
* role
* associated with what skin disorder(s)?
* contents
* major basic protein
* cationic protein
* catalase
* role: allergies, parasites
75
urticaria
* cause
* presentation
* cause: mast cell degranulation (immediate type hypersensitivity) that leads to vascular reaction
* presentation: **wheel**
76
what is the pilosebaceous unit and its components?
pilosebaceous = hair/oil unit
* hair follicle
* two glands: sebaceous + apocrine
* erector pili muscle
77
label the picture
* yellow - hair follicle
* blue - sebaceous glands
* red - epidermis
* green - dermis
78
# 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
79
outline the growth phases of the hair cycle
* anagen: active growth (2-6 years)
* catagen: regression (2-3 weeks)
* telogen: resting phase (3 months)
80
acne vulgaris
* definition
* causes
* definition: **disorder of pilosebaceous unit**
* causes:
* hair follicle plugging
* sebaceous gland activity
* p. acnes bacteria
* androgens
81
* 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_
82
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
