Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MSS Weeks 3-5 > Epidermis, Dermis, and Basement Membrane > Flashcards

Epidermis, Dermis, and Basement Membrane Flashcards

1
Q

What is the epidermis derived from?

A

Ectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the layers of the epidermis?

A
  1. Stratum corneum/Cornified layer
  2. Stratum granulosum/granular layer
  3. Stratum spinosum/Spinous layer
  4. Stratum Basale/Basal layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which layer contains keratinocyte stem cells?

A

Stratum Basale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some of the functions of the skin?

A
  • Maintenance of body temperature
  • Recognition of outer enivronment
  • Defense against microorganisms
  • Protection from harmful materials in the external environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What layer of the epidermis is only on the palms and soles and what two layers is it located between?

A

Translucent layer (Stratum Lucidum) - present between the granular layer and the cornified layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do the stem cells of the basal layer form keratinocytes?

A
  1. Each stem cell divides into a daughter stem cell and a transient amplifying cell
  2. The transient amplifying cell undergoes a few more clel division cycles before separating from the basement membrane
  3. Now known as a keratinocyte, the cell moves upward to join the stratum spinosum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which layer of the skin contains the most keratinocytes?

A

The spinous layer (stratum spinosum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What holds together the keratinocytes of the spinous layer?

A

Desmosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What types of junctions are responsible for keratinocyte communication and adhesion?

A

Gap junctions

Adherens junctions

Tight junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Desmosomes are protein complexes that connect _________ and their ________ ________ ________ ________

A

Keratinocytes; keratin intermediate filament network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What type of proteins are keratins?

A

alpha helical proteins that make up the intermediate filaments of the skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two types of keratins and how do they eventually form intermediate filaments?

A

Type I (acidic) and Type II (basic) keratins heterodimerize - two heterodimers form a tetramer that is further organized into keratin intermediate filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Keratin intermediate filaments connect to _______ and __________ to form the cytoskeleton network of the epidermis

A

Desmosomes; hemidesmosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the two types of granules secreted by keratinocytes in the granular layer? What is the function of each?

A

Keratohyalin granules - filled with proteins that are important for formation of the cornified envelope (profilaggrin)

Lamellar granules - Contain lipids such as ceramides and cholesterol that are important in forming the lipid barrier of the cornified layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of granules are responsible for promoting the desquamation of the cornified layer?

A

Lamellar granules containing hydrolytic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of cells make up the cornified layer?

A

Corneocytes (anuclear)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which sites lack a cornified layer?

Where are the thickest cornified layers?

A

Mucosal sites such as the mouth lack a cornified layer

Thickest cornified layer is present on the palms and soles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where are melanocytes present? What is their main function?

A

Melanocytes are present in the basal layer - responsible for producing melanin, the pigment that determines skin color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where are Langerhans cells mostly found?

A

Spinous layer (but present throughout the dermis and epidermis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is cornification/keratinization

A

The process of keratinocyte migration and maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What changes occur as the keratinocyte migrates to the skin surface?

A

It flattens out and loses its water content - progressively loses its cellular organelles and nucleus and releases its intracellular granules - eventually shed in the process of desquamation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the transit time of keratinocyte through the epidermis?

How long does it take the keratinocyte to migrate from the basal layer to the granular layer?

A

28 days; 14 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The main protein that makes up the cornified envelope is _______ which is processed from __________ and ________

A

Filaggrin; profilaggrin and involucrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The main lipid that makes up the cornified envelope is ________

A

ceramide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are two disorders of the epidermis?

A

Pephigus Vulgaris

Ichthyosis Vulgaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What causes Pemphigus Vulgaris? What proteins are affected?

A

Autoantibodies against desmosomal proteins, specifically Desmoglein 1 and 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Pemphigus Vulgaris

What happens as a result of weakened desmosomes?

A

Intraepidermal blistering occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What areas does Pemphigus Vulgaris affect?

A

Affects mucosal sites such as the mouth nose and genitalia as well as any cutaneous site on the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How is Pemphigus Vulgaris treated?

What can happen if it is not treated?

A

Treatment is with immunosuppressive medications such as prednisone, azathioprine and mycophenolate mofetil (Rituximab has been increasingly used in recent years)

It can be fatal when not treated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Who is most at risk for Pemphigus vulgaris?

A

Elderly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What type of inheritance does Ichthyosis Vulgaris have?

What gene is mutated?

A

Autosomal dominant

Mutations in the profilaggrin gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the presentation of Icthyosis Vulgaris and where does it preferentially occur?

A

Presents with large scales on the body

The extremities, primarily the shins are preferentially affected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are the three types of UV light?

A
  • UVA (200-280 nm)
  • UVB (280-320 nm)
  • UVC (320-400 nm)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Which two types of UV light penetrate the skin?

Which is responsible for erythema and sunburn?

Which is responsible for tanning and photaging?

A

UVA and UVB penetrate the skin

UVB is responsible for erythema and sunburn

UVA causes tanning and photoaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What type of skin cancers are associated with UV light?

What skin diseases are treated by UV phototherapy?

A

Skin cancers: Basal cell carcinoma; squamous cell carcinoma; melanoma

UV phototherapy: Psoriasis; atopic dermatitis; mycosis fungoides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is SPF?

MED?

How is SPF calculated?

A

SPF (sun protection factor) provides a measur of protection against UVB exposure and sunburns (not UVA)

MED (minimal erythema dose) is the minimum amount of UVB tha tcauses skin redness at 24 hours

SPF = MED protected/MED unprotected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Sunscreen should be applied at least __ minutes prior to sun exposure

An adult will need __oz of sunscreen to cover the entire body

Reapply sunscreen every __ hours

A

15; 1; 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

The dermis is derived embyrologically from the _______

A

mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are functions of the dermis

A
  • Provide the skin with structure and flexibility
  • Vascular support for th eskin
  • Immunologic protection
  • Nerve sensation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What adnexal structures are contained in the dermis?

A
  • Eccrine (sweat) glands
  • Sebaceous (oil) glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the two layers of the dermis? Describe their appearance

A
  • The superficial layer - the papillary dermis
    • ​More cellular and has fine, loosely woven collagen
  • The lower layer - the reticular dermis
    • ​Fewer cells and contains coarse tightly packed collagen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the main component of the dermis?

A

ECM

43
Q

What functions does the ECM regulate in the Dermis?

A

Adhesion

Migration

Division

Apoptosis

44
Q

Main components of the ECM in dermis

A

Colagen, elastic fibers, and extrafibrillar matrix

45
Q

Collagen makes up ___% of the skin’s volume and __% of the skin’s dry weight

A

20%; 75%

46
Q

How many types of collagen are there?

How many types are in the skin?

What are the top two most abundant types of collagen in the skin?

A

There are 28 types of collagen with 12 types present in the skin

Collagen I is the most abundant collagen of the skin followed by collagen III

47
Q

What is the function of elastic fibers in the dermis?

What are they composed of?

A

Elastic fibers are responsible for skin elasticity and the ability to be stretched and still return to the original form

They are composed of microfibrils, primarily made up of fibrillin, and amorphous elastin

48
Q

What is the non-collagen, non-elastin component of the dermis? What are its components?

A

Ground substance - composed of water, electrolytes, plasma proteins and proteoglycans

49
Q

What is the most prominent GAG in skin? What is unique about it?

A

Hyaluronic acid - unique for not being covalently linked to a protein

50
Q

What are the predominant cells of the dermis and what are they derived from?

A

Fibroblasts are the predominant cells of the dermis and are derived from mesoderm

51
Q

What is the main role of the fibroblast in the dermis?

A

The main role of the fibroblast is the production and secretion of the components of the extracellular matrix

52
Q

Endothelial cells in the dermis are arranged in a _______ ________

A

vascular network

53
Q

The _______ ______ ______ in the papillary dermis and the _____ _______ in the lower reticular dermis are composed of arterioles and venules

A

Interconnected superficial plexus

Deep plexus

54
Q

Aside from circulation, what other functions do the blood vessels of the dermis have?

A

Temperature regulation

Leukocyte trafficking

Wound healing

55
Q

What do the autonomic nerves of the dermis innervate - what is the result of each innervation?

A

Endothelial cells - control vascular tone

Smooth muscles of the hair follicle - control the pilomotor response

Eccrine glands - mediate sweating

56
Q

What are the special sensory receptors in the skin?Where are they present and what are their functions?

A

Pacinian corpuscles - present in weight-bearing surfaces (as well as lips, nipples, penis and clitoris) - located in deep dermis and subq tissue - detect pressure

Meissner’s corpuscles - Located just below the peidermis in the dermal papillae - sensitive to light touch and are concentrated on palms and soles

57
Q

The collagen molecule contains 3 nucleotide repeats where every third amino acid is _______

What are the other two residues that commonly make up the other positions?

A

Glycine; Proline and hydroxyproline

58
Q

What are the steps of collagen synthesis?

A
  1. RER translation
  2. ER and Golgi modification
    1. Cleavage of signal peptides
    2. Hydroxylation
    3. Glycosylation
  3. Assocation of alpha chains and folding into procollagen triple helix
  4. Protease cleavage of N-and C- terminals
  5. Assembly and cross-linking with other collagens to form collagen suprastructure
59
Q

Marfan Syndrome results from what mutation?

What type of inheritance is associated with this disorder?

A

Mutations in fibrillin

Autosomal dominant

60
Q

Abnormalities associated with Marfan’s syndrome

  • Musculoskeletal (4)
  • Eye (2)
  • Skin (1)
  • Cardiovascular (2)
A
  • Musculoskeletal (4)
    • tall and thin body type
    • long lims and fingers
    • scoliosis
    • flexible joints
  • Eye (2)
    • nearsightedness (myopia)
    • ectopia lentis (dislocation of the lens)
  • Skin (1)
    • Striae (strech marks)
  • Cardiovascular (2)
    • Aortic aneurysm
    • Mitral valve prolapse
61
Q

Ehler Danlos syndrome is caused by mutations that interfere with…

A

Structure, production, processing, or assembly of collagen

62
Q

Clinical features of Ehler Danlos syndrome

A

Fragile skin

Flexible joints (joint dislocations and early arthritis)

Severe scoliosis

63
Q

Morphea is characterized by…

A

Sclerosis or thickening of collagen

64
Q

How does morphea appear on the skin?

A

It appears as erythematous and indurated plaques that slowly expand

65
Q

What other skin disease besides morphea is characterized by sclerosis?

A

Systemic sclerosis

66
Q

What are the two principle forms of systemic sclerosis?

A

Limited systemic sclerosis

Diffuse systemic sclerosis

67
Q

What are the features of limited systemic sclerosis (CREST)

A
  • Calcinosis cutis
  • Raynaud phenomenon
  • Esophageal dysmotility
  • Sclerodactylyl (thickening and tightening of fingers)
  • Telangectasia of the face
68
Q

What are the features of diffuse systemic sclerosis?

A
  • Widespread sclerosis of the skin
  • Pulmonary fibrosis
  • Renal failure
  • Gastrointestinal disease
  • Cardiac disease
69
Q

Wound healing stages?

A
  • Hemostasis
  • Inflammation
  • Proliferation
  • Maturation
70
Q

What is the first step of hemostasis

A

Reflexive vasoconstriction

71
Q

What induces vasoconstriction in hemostasis?

A

Endothelin (released from endothelium)

Circulating catecholamines (epinephrine, norepinephrine)

Prostaglandins from injured cells

Bradykinin, Serotonin, and thromboxane A2 (from platelet activation)

72
Q

What are the physical signs of inflammation?

A

Erythema, heat, edema, and pain

73
Q

What are the signs of inflammation on the cellular level?

A

Vessel dilation

Increased vascular permeability

Leukocyte recruitment to the site of injury

74
Q

How does edema result from inflammation?

A

Increased permeability leads to transport of intravascular fluid, proteins and cells into the extravascular space resulting in wound edema

75
Q

What do fibroblasts, smooth muscle cells and endothelial cells do to promote healing?

A

These cells infiltrate the wound and reesetablish tissue continuity through matrix deposition, angiogenesis and epithelialization within 4-12 days post injury

76
Q

What is the last cell population to enter a wound? What attracts them?

A

Fibroblasts are the last cell pop. to enter a wound, they are attracted by platelet derived products (PDGF, IGF-1, TGF-ß)

77
Q

How does epithelialization occur

A
  • Epidermal thickening along the wound edges -
  • Attachments between hemidesmosomes and basement membrane are broken down allowing cells to migrate
  • The movement of basal cell parallels collagen orientation
  • Contact inhibition signals stop cell migration
  • Subsequent celular proliferation leads to a multilayer epidermis
78
Q

What is maturation in wound healing?

A

Inflammatory cells are cleared from scar tissue

Most fibroblast undergo apoptosis

Blood vessels in the scar become more mature

Collagen maturation

79
Q

What is below the dermis? What is it derived from? What is its function?

A

Subcutaneous fat derived from mesoderm

Function is the storage of energy in the form of fats - also provides insulation for the body and shock absorption

80
Q

What are the main cells of the subcutaneous fat? How do they appear?

A

Adipocytes

They appear as large clear cells with the nucleus displaced to one edge

81
Q

What type of disease is Erythema Nodosum (EN)? In what demographic is this disease most common?

A

EN is a panniculitis (inflammation of subq fat) that is most common in young women

82
Q

What type of infection is most common in EN?

A

Upper respiratory streptococcal infection

83
Q

What is the classic presentation of EN

A

Tender red nodules that arise on the shins

84
Q

What are the ultrastructues of the basement membrane zone (BMZ)?

A
  • Hemidesmosomes (BP 230, BP 180)
  • Lamina Lucida (BP 180)
  • Lamina Densa (laminin 332, collagen IV)
  • Sublamina densa (collagen VII)
85
Q

What are Hemidesmosomes?

A

Small structures on the inner surface of basal keratinocytes that are composed of many structural proteins - similar to desmosomes except only attach one cell (vs. two) to extracellular matrix

86
Q

What is BP 230 (Bullous Pemphigoid Antigen 1)

A

BP 230 belongs to the plakin family of proteins - has cytoplasmic localization and is important for the organization of the cytoskeletal architecture

87
Q

What is BP 180 (Bullous Pemphigoid Antigen 2)?

A

Also referred to as type XVII collagen - transmembrane protein connecting basal keratinocytes and cytoskeleton to dermal collagen VII

88
Q

What is the Lamina Lucida

A

Thin structure underlying hemidesmosomes - may be an artifact of tissue preparation and dehydration

89
Q

What type of collagen is the lamina densa composed of? What else is a component?

A

Type IV collagen

Laminins

90
Q

What is the most abundant colagen of the BMZ?

A

Collagen Type IV - comprises more than half its mass

91
Q

Collagen IV is a _______ which polymerizes into a ______ _______ and lattic formation

A

heteropolymer; triple helix

92
Q

What is the key BMZ laminin and what does it do?

A

Laminin 332 binds to transmembrane protein of the hemidesmosome integrin α6β4 using the G domain on its α chain as well as to type VII collagen using its NC-1 domain, bridging the BMZ

93
Q

What type of collagen is in the sublamina densa and what does it do?

A

Type VII collagen is necessary to maintian epidermal-dermal cohesion sinci it binds to both type I and type IV collagens which futher allows the type VII collagen to join the lamina densa to the papillary dermis

94
Q

Explain a Routine biopsy

A

Taken from the edge of blister and processed by regular histologic staining to determine blister level and inflammatory infiltrate

95
Q

Direct Immunofluorescence (DIF) vs. Indirec immunofluorescence (IIF)

A

DIF - detects IgGs and complement within biposy speciments - skin samples from peilesional skin (detect in situ)

IIF - detects circulating antibodies against BMZ in patients serum - patient serum applied to foreign substrate - antigen antibody complex detected by fluorescein-conjugated antibody

96
Q

Two ways in which diseases can target the BMZ

A
  1. Inherited mutations in the genes that encode for their various protein components
  2. Acquired autoantibodies that attack specific proteins
97
Q

Bullous Pemphigoid

Most common demographic:

Antibodies directed against:

Treatment:

A

The most common autoimmune bullous dermatosis

Most common demographic: Elderly

Antibodies directed against: BP230 and BP180

Treatment: high potency steroids; oral steroids and immunosuppresants used for severe disease

98
Q

Blisters in Bullous Pemphigous

A

Starts with highly pruritic utricaria without blistering​

Tense blisters with serous or hemorrhagic conent appear in phases

Roof of the blister consists of entire epidermis (extremely stable compared to pemphigus group)

99
Q

Mucous Membrane Pemphigoid

Most common demographic:

Antibodies against:

A

Most common demographic: elderly

Antibodies against: Majority of patients have antibodies against BP180 but some have antibodies targeting BP230, integrin ß4 and laminin 332

100
Q

Characteristics of MMP (Mucous membrane pemphigoid)

A

Recurrent blistering of mucous membranes and also the skin

Patients develops scars, strictures, synechiae and in 20% of cases - blindness

101
Q

Epidermolysis Bullosa Acquisita (EBA)

Target antigen:

Characteristics:

A

Target antigen: Type VII collagen

Characteristics: Slight trauma elicits blistering and erosions of the skin - sites of predilection are mechanically-stressed areas such as hands, feet, elbows and knees

102
Q

Epidermolysis Bullosa characteristics

A

Congenital absence or malfunction of structural proteins leads to erosions and blisters after minimal mechanical trauma

103
Q

Type of inheritance and Targeted proteins for…

Epidermolysis bullosa simplex:

Junctional EB:

Dystrophic EB:

A

Epidermolysis bullosa simplex: inherited in autosomal dominant manner - target proteins are keratins 5 and 14

Junctional EB: Inherited in an autosomal recessive manner - target proteins are laminin 332 and BP 180 and BMZ

Dystrophic EB: Inherited in both autosomal dominant and recessive - target protein is type VII collagen of the dermis

MSS Weeks 3-5 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions