GALDERMA 1 BASIC SCIENCE Flashcards

Question

Which of the following amino acids are typically found in elastic fibers? 1 Desmosine 2 Isoleucine 3 Proline 4 Hydroxyproline 5 Glycine

Answer 1

Desmosine Desmosine and isodesmosine are typical amino acids found in elastic fibers. Glycine, proline and hydroxyproline are found as components of collagen. Isoleucine is not specific for elastin fibers.

Answer 2

When an intact epidermis shears away from the underlying dermis, leaving a moist surface Nikolsky sign can be seen when an intact epidermis shears away from the underlying dermis, leaving a moist surface (seen in pemphigus vulgaris, staphylococcus scalded skin syndrome (SSSS), and toxic epidermal necrosis). Spreading bulla phenomenon with pressure on an intact bulla is referred to as Asboe-Hansen sign, commonly seen with pemphigus vulgaris. Swollen, itchy and or red after stroking the skin is referred to Darierâs sign and can be seen in systemic mastocytosis or urticaria pigmentosa. Central depression within a lesion when squeezed is referred to as the dimpling sign and is seen in dermatofibromas. Disappearance of color or blanching when the lesion is pressed is commonly found on vascular lesions

Answer 3

``` Sonic hedgehog Sonic hedgehog (Shh), a signaling molecule secreted by ectodermal cells of the developing hair follicle, appears to be critical in mediating the transition from telogen to anagen during postnatal hair cycling ```

Answer 4

S-100 Eccrine glands stain S-100 and CEA positive. The remaining stains would not be expected to stain normal eccrine sweat glands. Prussian blue (Perl�s) is an iron stain which stains iron or hemosiderin bright blue. Giemsa stains mast cell granules purple (heparin in the granules) and can also be useful in staining in Leishmaniasis. Verhoeff von Gieson is a stain for elastic tissue that stains blue-black. Steiner stain is a silver stin for spirochetes similar to a Warthin Starry or Dieterle stain.

Answer 5

A higher degree of dispersion of melanosomes in keratinocytes More darkly pigmented races show a greater production of melanosomes in the melanocyte, melanosomes with a higher degree of melanization, larger melanosomes, a higher degree of dispersion of melanosomes in the keratinocytes, and a slower rate of melanosome degradation.

Answer 6

Fuchter lines Fuchter lines are vestigial lines in which the dorsal surface has more melanocytes than ventral surface. Wallace's lines are the well-demarcated lines around the margin of the foot and hand.

Answer 7

E-cadherin E-cadherin is responsible for the adhesion of Langerhan cells to the epidermis. There are two major subclasses of cadherins which mediate cell adhesion and play a fundamental role in normal development, classic (E-,P-,N-cadherin) and desmosomal (desmoglein and desmocollin). They depend on calcium for their function.

Answer 8

Laminin 5 Anchoring filaments exist within the lamina lucida. They are primarily comprised of laminin 5 and BP180. Laminin 5 is a cross-shaped assembly of 3 classes of polypeptides, a, b, g. The anchoring filaments function as a structural network to which other proteins attach, and they function as signaling molecules that transmit morphogenetic information to transmembrane proteins of the basal cell layer (such as the integrins). Laminin 5 is also called epiligrin and binds to the a6b4 integrin at the hemidesmosome.

Answer 9

Fibronectin Granulation tissue forms approximately four days after injury. It is composed of new capillaries, macrophages, fibroblasts, and blood vessels. The formation is dependent on the presence of fibronectin. There tends to be an ordered sequence of matrix deposition. Fibronectin is deposited first followed by collagen 3 and then collagen 1. Granulation tissue primarily contains type 3 collagen.

Answer 10

Fibrillins and fibulins Elastic fibers are comprised of elastin as well as microfibrillar proteins including fibrillins and fibulins. Hyaluronic acid is a glycosaminoglycan found in the extracellular matrix of the dermis. Collagen II is the predominant collagen found in cartilage. Laminin 5 and BPAG2 are important anchoring filaments in the basement membrane zone. Desmoplakin and plakoblobin are proteins found in the anchoring plaques of desmosomes in the epidermis.

Answer 11

All of the answers are correct The above listed drugs, as well as beta-lactam antibiotics, antifungals such as ketoconazole and griseofulvin, are known to be secreted into eccrine sweat ducts. This feature may explain the development of neutrophilic eccrine hidradenitis and eccrine squamous syringometaplasia in the context of chemotherapy.

Answer 12

Vascular smooth muscle cells Glomus cells are derived from Suquet-Hoyer canals. They are vascular smooth muscle cells that allow the rapid shunting of blood from the arterioral to venular system, bypassing the capillaries. This process occurs primarily on the palms and soles.

Answer 13

Intercellular IgG and C3 and linear IgG and C3 along the basement membrane zone Senear-Usher syndrome, or pemphigus erythematosus, is a variant of pemphigus foliaceus characterized by crusted papules and plaques with a seborrheic distribution (malar region, scalp, upper chest and back). They demonstrate in-vivo IgG and C3 deposition on keratinocyte cell membranes and the basement membrane zone, in addition to circulating anti-nuclear antibodies.

Answer 14

Macrophage The macrophage is required for wound healing. The macrophages debride tissue, secrete collagenase and stimulate expression of FGF, IL-1, TGF-beta, PDGF and TGF-alpha thus facilitating transition from inflammation to repair.

Answer 15

The presence of pheomelanin Hair color is determined by melanocytes. The melanocytic activity of follicular melanocytes is coupled to anagen � hair is only pigmented when it is growing. Pigment is produced in the matrix area of follicle, above the follicular papilla. Eumelanin is the pigment of brown/black hairs, and pheomelanin is the pigment of red/blonde hairs. Intensity of color is proportional to the amount of pigment. The absence of pigment produces white hair, and markedly reduced pigment produces gray hair.

Answer 16

Decapitation secretion Apocrine glands are adnexal glands that are quiescent until puberty. They are found in the axillae, the anogenital region, mammary glands, Moll's gland of the eyelid, and ceruminous glands of the external auditory meatus. They develop from the upper bulge of the hair follicle during embryology. Once active, apocrine glands secrete their contents by means of decapitation secretion. During this process the apical portion of the gland pinches off and enters the lumen of the gland.

Answer 17

Postganglionic sympathetic fibers with acetylcholine as the principal neurotransmitter Eccrine glands are innervated by postganglionic sympathetic fibers with acetylcholine as the principal neurotransmitter. This explains why medications associated with anticholinergic side effects may be associated with hypohidrosis.

Answer 18

Collagen III Granulation tissue begins to form four days after injury and is composed of new capillaries, macrophages, fibroblasts, blood vessels and primarily collagen type III. Formulation of granulation tissue is dependent on the presence of fibronectin and progresses through an orderly sequence of matrix deposition: fibronectin to collagen III then finally collagen I.

Answer 19

Central depression within a lesion when squeezed along its margins Central depression within a lesion when squeezed is referred to as the dimpling sign and is seen in dermatofibromas. Nikolsky sign can be seen when an intact epidermis shears away from the underlying dermis, leaving a moist surface (seen in pemphigus vulgaris, staphylococcus scalded skin syndrome (SSSS), and toxic epidermal necrosis). Spreading bulla phenomenon with pressure on an intact bulla is referred to as Asboe-Hansen sign, commonly seen with pemphigus vulgaris. Swollen, itchy and or red after stroking the skin is referred to Darierâs sign and can be seen in systemic mastocytosis or urticaria pigmentosa. Disappearance of color or blanching when the lesion is pressed is commonly found on vascular lesions

Answer 20

K16 K16 and K6 act as markers for hyperproliferative keratinocytes. They are found in skin disease such as psoriasis, warts, actinic keratoses, and SCC's.

Answer 21

Spreading bulla phenomenon with pressure on an intact bulla Spreading bulla phenomenon with pressure on an intact bulla is referred to as Asboe-Hansen sign, commonly seen with pemphigus vulgaris. Nikolsky sign can be seen when an intact epidermis shears away from the underlying dermis, leaving a moist surface (seen in pemphigus vulgaris, staphylococcus scalded skin syndrome (SSSS), and toxic epidermal necrosis). Swollen, itchy and or red after stroking the skin is referred to Darierâs sign and can be seen in systemic mastocytosis or urticaria pigmentosa. Central depression within a lesion when squeezed is referred to as the dimpling sign and is seen in dermatofibromas. Disappearance of color or blanching when the lesion is pressed is commonly found on vascular lesions

Answer 22

Stratum granulosum Pilar cysts do not have a granular layer, they do have all the other layers.

Answer 23

Lipofuschin Chromhidrosis refers to the secretion of pigmented sweat, most commonly yellow, green or black. It reflects the rich lipofuschin content of apocrine sweat. Extrinsic apocrine chromhidrosis results from staining of sweat and garments by chromogenic bacteria, such as Corynebacterium spp.

Answer 24

Wax esters As human sebum exits the sebaceous gland, its major constituents are squalene, cholesterol, cholesterol esters, triglycerides, and wax esters. With passage through the hair follicle, triyglycerides in the sebum become hydrolyzed by bacterial enzymes, so that by the time the sebum reaches the skin surface, it contains free fatty acids, mono- and diglycerides in addition to the original components. Human sebum is distinguished by the presence of wax esters and squalene. The lipids of human internal organs contain no wax esters and little squalene. The squalene that is produced in internal organs is quickly converted to lanosterol and then to cholesterol, so it does not remain in its original form. Human sebaceous glands do not convert squalene to sterols.

Answer 25

Amnion Type VII collagen is present in anchoring fibrils and amnion. Fetal skin and blood vessels contain type III collagen. The aorta contains type VI collagen. Bone contains type I collagen.

Answer 26

Elastic fibers are 90% elastin wrapped in fibrillin Elastic fibers are responsible for much of the elasticity of the dermis. They are essentially 90% elastin wrapped in fibrillin. They form 4% of the dry weight of the skin. Fibrillin 1 is mutated in Marfan syndrome. Oxytalan fibers run PERPENDICULAR from the DEJ within the superficial papillary dermis. Elaunin fibers run parallell in thin bands within the reticular dermis.

Answer 27

KIT Mucosal melanomas tend to have an activating mutation in KIT. GNAQ mutations are seen in both uveal melanomas and blue nevi. Cyclin dependant kinase 4/6 binds cyclin D and together phosphorylate Retinoblastoma. HDM2 targets p53 for ubiquitination.

Answer 28

Ceramide The major component of lamellar granules of the keratinocytes is ceramide. These play a major role in the barrier function of the skin.

Answer 29

Pseudoxanthoma elasticum There are many genodermatoses that involve elastin. Pseudoxanthoma elasticum shows increased glycosaminoglycans on elastic fibers, calcium deposition and accumulation of fragmented and calcified elastic fibers. Cutis laxa shows decreased desmosine and lysyl oxidase. In Marfan sydrome there is decreased fibrillin I and fragmentation of elastic fibers. Buschke-Ollendorf syndroms shows increased desmosine and increased amount of thickend elastic fibers. Other elastin disease are congenital contractural arachnodactyly from a mutation in fibrillin II and anetoderma which shows decreased desmosine and loss/fragmentation of elastic fibers. Classic type Ehlers-Danlos syndrome is caused by a defect in collagen V and not in elastin. Progeria is caused by a defect in lamin A. EHK is caused by a defect in keratin 1/10. Rothmund Thompson is caused by a defect in RecQL4, a helicase gene.

Answer 30

Pseudoxanthoma elasticum There are many genodermatoses that involve elastin. Pseudoxanthoma elasticum shows increased glycosaminoglycans on elastic fibers, calcium deposition and accumulation of fragmented and calcified elastic fibers. Cutis laxa shows decreased desmosine and lysyl oxidase. In Marfan sydrome there is decreased fibrillin I and fragmentation of elastic fibers. Buschke-Ollendorf syndroms shows increased desmosine and increased amount of thickend elastic fibers. Other elastin disease are congenital contractural arachnodactyly from a mutation in fibrillin II and anetoderma which shows decreased desmosine and loss/fragmentation of elastic fibers. Classic type Ehlers-Danlos syndrome is caused by a defect in collagen V and not in elastin. Progeria is caused by a defect in lamin A. EHK is caused by a defect in keratin 1/10. Rothmund Thompson is caused by a defect in RecQL4, a helicase gene.

Answer 31

Neutrophil Neutrophils migrate with monocytes concurrently, but arrive first in great numbers because of their abundance in circulation. Chemoattractants for the PMNs are fibrinogen, fibrin split products, C5a and leukotrienes. If wound contamination is controlled, PMN migration ceases within a few days and they become entrapped within the wound clot, undergo apoptosis or are phagocytosed by macrophages.

Answer 32

85% Most hair follicles are in anagen, and thus most hair follicles involve growing hair. The longer a hair follicle is anagen, the longer the hair can grow in length. Hairs of the scalp grow approximately 0.4 mm per day, and thus the date of your next hair cut can be accurately calculated.

Answer 33

Copper Melanin is synthesized from tyrosine vis the action of the enzyme tyrosinase (tyrosine to DOPA to DOPAquinone to melanin). Tyrosinase is a copper containing enzyme. The other elements are not specifically required for melanin synthesis.

Answer 34

CD6 CD6 and CD11c are expressed on all mononuclear phagocytic cells in the dermis. CD3 is a T-cell marker and CD20 is a B-cell marker. CD34 is expressed on mast cells and CD68 on macrophages.

Answer 35

8 weeks Epidermal stratification begins at about 8 weeks estimated gestational age and is completed by the 2nd trimester. Epideral stratification occurs when an 'intermediate layer' develops between the epidermal basal cells and the overlying layer of periderm cells. The periderm is an embryonic structure that covers the primitive epidermis until keratinization begins, at which point the periderm sloughs off and contributes to the protective covering of the newborn, the vernix caseosa. This intermediate layer is highly proliferative, such that by 24-25 weeks estimated gestaional age, the epidermis consists of 4 or 5 layers, in addition to the degenerating periderm.

Answer 36

Bullous pemphigoid Bullous pemphigoid is one of the many bullous diseases that may be found on the âroofâ of the blister, the others include pemphigoid gestationis, linear IgA bullous dermatosis, cicatricial pemphigoid. The other answer (except for bullous tinea, in which a salt split would not be performed) are those found on the âfloorâ of the blister (lamina densa).

Answer 37

Keratins 5 All subtypes of EBS are caused by a defect in keratins 5 & 14 except EBS with muscular dystrophy which is caused by a defect in plectin. An alpha-6-beta-4 integrin defect is seen in junctional epidermolysis bullosa (JEB) with pyloric atresia. Collagen VII defect is seen in EB aquisita (EBA), Bart's syndrome and dominant EB (DEB). Keratin 1 & 10 defects are not seen in any of the EB subtypes.

Answer 38

Loricrin Loricrin is the major component of the cornified envelope (CE). The proteins of the CE are synthesized in the spinous and granular layers. The CE is primarily a protein/lipid polymer formed within the differentiating layer of keratinocytes. The CE eventually exists outside of the cornified cells after the granular cell undergoes a programmed destruction (apoptosis). Self-destructing granular cells are called transition cells.

Answer 39

Type VII collagen Anchoring fibrils are found in the sublamina densa and are made up of collagen type VII. This collagen type is mutated in dystrophic epidermolysis bullosa, and targeted in epidermolysis bullosa acquisita and bullous lupus erythematosus.

Answer 40

Collagen IV Collagen IV is the main collagen component of basement membranes. Collagen I is the main collagen of mature dermis, bone and tendon. Collagen III is found in fetal skin, blood vessels and intestines. Tenascin-X is mutated in some forms of Ehlers-Danlos syndrome and is not associated with the basement membrane. Collagen VII makes up anchoring fibrils and amnion

Answer 41

Plectin is a member of the plakin family Plectin is a hemidesmosomal protein and is not present in the desmosome. It links intermediate filaments to the plasma membrane, crosslinks hemidesmosomal proteins, mutations result in epidermolysis bullosa simplex with muscular dystrophy and is a member of the plakin family.

Answer 42

Anchoring filaments attach the basal cell membrane to the lamin lucida The basement membrane zone is seen on staining with PAS stain. It appears as a homogenous band approximately 1 micron thick at the dermo-epidermal junction. The hemidesmosomal complex and basement membrane zone play an integral role in maintaining cellular adhesion. Anchoring filaments (primarily composed of laminin 5 and BPAG2) attach the basal cell membrane to the lamina densa NOT lamina lucida.

Answer 43

K16/K6 - palms and soles Keratin 1 and 10 are found in the stratum spinosum. K5 and K14 are found in the basal layer. K3 and K12 are found in the suprabasilar cells of the cornea. K4 and K13 are found in the non-cornifying cells of stratified mucosa. K16 and K6 are found in the palms and soles.

Answer 44

Inhibitor of CTLA-4 Ipilimumab is an antibody to CTLA-4, this interaction causes inhibition of CTLA-4 which normally inhibits T cell co-activation by binding to B7 (which normally binds to CD28).

Answer 45

The DEJ deposition is granular The DEJ deposition is granular. The DIF is positive in the vast majority of cases. Deposition of IgM and fibrinogen is within cytoid bodies in the superficial dermis. There is no deposition of IgM within the spinous layer of the epidermis.

Answer 46

14 days Once a basal cell leaves the basal layer in humans, normal transit time to stratum corneum is at least 14 days. Transit time through the stratum corneum to desquamation requires 14 more days.

Answer 47

Granular fluorescence throughout the cytoplasm and nucleus of basal keratinocytes Granular fluorescence throughout the cytoplasm and nucleus of basal keratinocytes reflect the binding of Ro and La antigens and is unique to SCLE. Cytoid bodies and Immune deposits along dermal-epidermal junction are seen in both DLE and SCLE. Granular deposits along the basement membrane are seen in dermatitis herpetiformis and a chicken-wire pattern of staining is seen in pemphigus vulgaris.

Answer 48

vernix caseosa During the second trimester of fetal development, the periderm is sloughed from most of the skin surface revealing the underlaying epidermis. The periderm becomes part of the protective coating, vernix caseosa, together with the shed lanugo, sebum and other amniotic fluid materials. Bolognia p.38

Answer 49

Medulla _ cortex _ hair shaft cuticle _ inner root sheath cuticle _ Huxley's layer _ Henle's layer

Answer 50

Swollen, itchy and or red after stroking the skin Swollen, itchy and or red after stroking the skin is referred to Darier's sign and can be seen in systemic mastocytosis or urticaria pigmentosa. Nikolsky sign can be seen when an intact epidermis shears away from the underlying dermis, leaving a moist surface (seen in pemphigus vulgaris, staphylococcus scalded skin syndrome (SSSS), and toxic epidermal necrosis). Spreading bulla phenomenon with pressure on an intact bulla is referred to as Asboe-Hansen sign, commonly seen with pemphigus vulgaris. Central depression within a lesion when squeezed is referred to as the dimpling sign and is seen in dermatofibromas. Disappearance of color or blanching when the lesion is pressed is commonly found on vascular lesions

Answer 51

Langerhans cells Most of the contact allergens are low-molecular weight chemicals, which after penetrating into the skin, have to couple with host proteins to be able to act as full antigens. These are called haptens. Upon epicutaneous application to a naive host, Langerhans cells take up the hapten, process it and migrate towards the regional lymph nodes, where the anitgen is presented to the naive T cells.

Answer 52

heparan sulfate proteoglycan 5 alpha-6-beta-4 integrin All of the listed proteins are present in the lamina densa except alpha-6-beta-4 integrin, which connects the hemidesmosome to laminin 5 in the lamina lucida. The heparin sulfate proteoglycans (perlecan) are negatively charged, thus serve as a permeability barrier. The other listed proteins do not serve this function in the lamina densa. Collagen IV is the main basic basement membrane scaffold. Defects in Collagen IV have been linked to Alport�s and Goodpasture�s syndrome. Nidogen has a �dumbbell� shape and binds both laminins and collagen IV in the lamina densa.

Answer 53

Cytokeratin 20 Cytokeratin 20 is a specific marker for the Merkel cell. Merkel cells are mechanoreceptors located at body sites requiring high tactile sensitivity. Keratinocyte deformation results in a secretion of chemokines by Merkel cells, which make synaptic connection with neurons.

Answer 54

Mast cell Electron microscopy of mast cells demonstrates large long villi at the periphery and round or oval secretory granules. Langerhans cells show a folded nucleus and rarely phagocytized melanosomes on electron microscopy. Their characteristic feature is the presence of Birbeck granules whose disk shape with one or two vesicles at either end represents a tennis raquet. Examination of melanocytes shows an absence of tonofilaments or desmosomes with characteristic melanosomes in various stages of formation. Macrophages often contain phagocytized material within phagosomes.

Answer 55

K5,14 K5 and K14 are expressed in the stratum germinativum (basal layer) and are defective in epidermolysis bullosa simplex. They are still present in the stratum spinosum but are not made de novo in this layer. K4 and 13 are found in mucosal epithelium. K1 and 10 are expressed in suprabasal keratinocytes, K2e and 10 in the upper spinous and granular layers, and K3 and K12 in the cornea.

Answer 56

Palms Sebaceous glands secrete their contents in a holocrine fashion and are primarily under the influence of androgens. They secrete triglycerides, phospholipids, esterified cholesterol, waxes but not free cholesterol. They may be found in association with hair follicles or in some areas of modified skin such as the nipple/areola, labia minora, prepuce, vermilion border, and eyelids.

Answer 57

Zeis glands Zeis glands are sebaceous glands associated with eyelashes. Montgomery's tubercles are present on the areola, Tyson's glands on the labia minora and glans, and Fordyce's spots are located on the buccal mucosa.

Answer 58

Sebaceous glands Sebum is secreted continuously on the skin under hormonal glands. It contains squalene, cholesterol, cholesterol esters, wax, and triglycerides.

Answer 59

Stratum granulosum The proteins that make up the cornified cell envelope are synthesized in the spinous and granular cell layer. The stratum basale is not involved in production of these proteins and there is no protein synthesis in the stratum corneum. Melanocytes and Langerhans cells are components of the epidermis but are not involved in this process.

Answer 60

K13 Keratins are divided into acidic (type I) and basic (type II) subtypes. Keratin 13 is a type I keratin which is expressed suprabasally in adult epithelia and is associated with terminal differentiation. Renal transplant recipients have an increased risk of developing skin cancers and multiple warts. Factors contributing to this increased risk include human papillomavirus infection, immunosuppressive therapy, and exposure to ultraviolet radiation. Increased expression of K13 has been demonstrated in high-risk papillomas in this patient population.

Answer 61

``` 17 Acidic keratins (K10-20) are expressed from chromosome 17. Basic keratins (K1-9) are on chromosome 12. The other listed chromosomes are not involved in keratins. ```

Answer 62

Huxley�s layer contains melanin The inner root sheath is composed of three layers, which are the inner root sheath cuticle, Huxley layer, Henle layer. None of these layers contain melanin. All three layer keratinize by trichohyaline granules and disintegrate when they reach the isthmus of the hair follicle.

Answer 63

Not all basal cells have the potential to divide Not all basal cells have the potential to divide. Stem cells give rise to transient amplifying cells which give rise to the epidermal keratinocytes. Intermediate filaments in basal cells insert into desmosomes and hemidesmosomes. Keratins 5/14 are predominantly expressed. Microfilaments assist in upward movement of cells. Integrins regulate adhesion and initiation of differentiation.

Answer 64

Guinea pig esophagus The black fly or Simulium nigrimanum is the vector for pemphigus foliaceus. Immunofluorescence for this condition is best performed on guinea pig esophagus. Rat bladder and monkey esophagus are used for bullous pemphigoid and paraneoplastic pemphigus. Armadillo foot pads are used to culture leprosy.

Answer 65

All the options are correct The hair follicle converts gonadal or aderenal testosterone to dihydrotestosterone locally via 5-alpha reductase. It also cleaves proopiomelanocortin to ACTH, alpha-MSH, and B-endorphin via prohormone convertase. It also secretes corticotropin releasing hormone (CRH) as well as prolactin

Answer 66

lamellar granules are uniformly absent In Harlequin ichthyosis, the lamellar granules are uniformly abnormal or absent. On electron microscopy, there is no evidence of the lipid lamellae which form due to lamellar granule discharge into the region between the granular and cornified cells (Fitz v6, p493). This is suggestive of a primary defect in lipid synthesis and protein dephosphorylation resulting in faulty lamellar body formation and secretion (Bolognia, ch. 57). Harlequin fetus/ichthyosis can be divided into three types based on the microscopic appearance of the keratohyaline granules. Type I - normal, Type II - too small to be seen by light microscopy, Type III - absent keratohyaline granules. Demoyokin, band-6 protein (a plaque component) and plakoglobin are desmosomal proteins and not involved in Harlequin ichthyosis. Recently, the gene defect was localized a defect in the ABCA12 protein.

Answer 67

IL-6 Adipocytes secrete tumor necrosis factor (TNF)Î±, interleukin-6 (IL-6), leptin, adiponectin, angiotensinogen, and resistin. Specifically it has been shown that IL-6 mRNA levels in human subjects are significantly greater in adipose tissue than in other tissues known to express IL-6. It is thought that circulating IL-6 levels may be higher in obese patients, contributing to the development and progression of vascular disease in this patient population.

Answer 68

``` Lamina densa Anchoring filaments (smaller than anchoring fibrils) stretch from the plasma membrane through the subbasal dense plaque and the lamina lucida to the lamina densa. ```

Answer 69

9 weeks The first primordial hair follicles form at 9 weeks gestation on the eyebrows, upper lip and chin. The remaining follicles develop at 4-5 months in a cephalad to caudal direction. New follicles cannot develop in adult skin.

Answer 70

Present antigen to na� T cells in the lymph node. A dermal dendrocyte is a mononuclear phagocytic cell that is a type of antigen presenting cell. It is derived from the bone marrow and found both in the papillary and upper reticular dermis. This cell is highly phagocytic and synonymous with the melanophage that has ingested pigment. Dermal dendrocytes are likely very important to the afferent limb of the immune response.

Answer 71

Neural crest Melanocytes are derived from neural crest precursors and migrate to the epidermis, hair matrix, retinal pigment epithelium, ear (stria vascularis), leptomeninges, and mucous membranes. The other options listed are incorrect and are not involved with melanocytes.

Answer 72

K6b/17 Keratins 6b & 17 are expressed in the nail bed. K6a/16 is expressed in the outer root sheath and in hyperproliferative keratinocytes, 1/9 in palmoplantar suprabasalar keratinocytes, 2e/10 in the upper spinous and granular cell layers, and 4/13 are expressed in mucosal epithelium.

Answer 73

Pericardium Melanocytes are found in the stria vascularis of the ear, iris, leptomeninges and retina. There are no normal populations of melanocytes found in the pericardium.

Answer 74

CD34 CD34+ cells in the bone marrow are the precursors of mast cells. CD3 and CD20 are T and B cell markers respectively. CD6 is found on mononuclear phagocytic cells in the dermis, CD68 is a macrophage marker.

Answer 75

Cytoplasm Both androgen and corticosteroid receptors localize to the cytoplasm. Estrogen receptors are found in the nucleus. Progesterone receptors are distributed in both the nucleus and the cytoplasm.

Answer 76

Laminins provide signaling molecules that interact with other proteins to transmit morphogenetic information to the cell's interior Laminins do transmit signals to the cell's interior. They span from the plasma membrane of basal keratinocytes to the lamina DENSA, not lucida. Laminin 5 (also known as epiligrin) is part of a structural network in the basement membrane that also includes laminin 6.

Answer 77

Holocrine mechanism The sebaceous lobules have basal germinative cells and central sebocytes, which gradually become more distended with lipid vacuoles until they are shed into the lumen (holocrine secretion).

Answer 78

Collagen type VII Dystrophic epidermolysis bullosa results from mutations in Type 7 collagen. Type I collagen mutations are associated with osteogenesis imperfecta. Antibodies to Type II collagen are associated with relapsing polychondritis. Mutations in type V collagen result in the classic form of Ehlers Danlos while mutations in type III collagen result in the vascular form of Ehlers Danlos.

Answer 79

Fibronectin Fibronectin is a key player in wound healing, initially secreted by myofibroblasts. The bed/matrix of fibronectin provides an adherent base for migration into the wound, provides scaffolding for collagen fibrils and mediates wound contraction. Band-6 protein is a constituent of the desmosomes intracellular plaque. Entactin and nidogen are synonyms and are found in the dermal-epidermal junction, binding to laminin 1s alpha chain. Uncein is associated with anchoring filaments.

Answer 80

Keratins 5 and 14 Keratins 5 and 14 are intermediate filaments found in the basal layer of the epidermis that play a role in attaching basal layer keratinocytes to the basement membrane zone. Keratins 1 and 10 are found in more superficial layers of the epidermis. Desmogleins, desmoplakin, and desmoglobin are all components of desmosomes which attach keratinocytes to other surrounding keratinocytes. BPAG1 and BPAG2 are basement membrane proteins.

Answer 81

IL-23 IL-2 is a cytokine that primarily produced by T lymphocytes and acts on other T lymphocytes as a growth factor for both survival and differentiation. IL-3 is also produced by T lymphocytes and acts as a growth factor for cells of the myeloid lineage. IL-17 is an effector cytokine that is implicated in the pathogenesis of psoriasis and produced by Th17 cells. IL-22 is also an effector cytokine produced by T lymphocytes that contributes to epidermal acanthosis in psoriasis. All of these cytokines are not secreted from epidermal keratinocytes. IL-23, which promotes Th17 effector function, is secreted by epidermal keratinocytes and upregulated in psoriasis. The p40 subunit of IL-23 is the target of drug ustekinimab used to treat psoriasis.

Answer 82

Fordyce's spots Fordyce's spots are located on the buccal mucosa and vermilion border of the lips. Montgomery's tubercles are present on the areola, Tyson's glands on the labia minora and glans, meibomina and Zeis glands are present on the eyelids.

Answer 83

36 keratinocytes One melanocyte and 36 keratinocytes make up one epidermal melanin unit. This melanocytes transfers pigment to these keratinocytes.

Answer 84

It is a member of the plakin family BPAg1 is a member of the plakin family, which includes envoplakin, periplakin, desmoplakin, plectin, and BPAg1. BPAg2 is pathogenic in cicatricial pemphigoid and pemphigoid gestationis. BPAg1 is pathogenic in paraneoplastic pemphigus. Desmoglein 3 is pathogenic in pemphigus vulgaris and coprecipitates with plakoglobin.

Answer 85

Are found everywhere on the skin except palms and soles Sebaceous glands are found everywhere on the skin except on the palms and soles. They are multilobular, emptying into the sebaceous duct. Most sebaceous glands are associated with hair follicles, but free glands exist, especially on the lip (Fordyce spots), on the nipple/areola (Montgomery�s tubercles), Meibomian glands of the eyelids and Tyson�s glands on the genitalia. The size of the sebaceous glands are not related to the size of the associated follicle. The sebaceous gland enlarges at puberty in response to increased androgens.

Answer 86

Neonatal LE DIF is of no value in the diagnosis of scleroderma, morphea, and neonatal LE. DIF of lichen planus is positive in the vast majority, with granular DEJ deposition and IgM and fibrinogen staining within cytoid bodies in the superficial dermis. In MCTD DIF shows IgG deposits within epidermal cell nuclei, and rarely along the DEJ. In SLE, while serology is more reliable, DIF can show DEJ deposition in the lupus band test. DIF of erythema multiforme shows immunoglobulin within superficial vessel walls, DEJ, and cytoid bodies.

Answer 87

Ferrochelatase All of the listed enzymes are copper containing or dependent except ferrochelatase. Lysyl oxidase facilitates crosslinking of fibrillin in elastic fibers. ATP7a is deficient in Menkes Kinky Hair Syndrome. Cystathione beta-synthase is defective in homocystinuria. Tyrosinase catalyzes the first 2 steps, and at least 1 subsequent step, in the conversion of tyrosine to melanin. Ferrochelatase mutation leads to excess protoporphyrin production and photosensitivity.

Answer 88

Papillary dermis 5 Subcutaneous fat Mast cells are found in the greatest density in the papillary dermis, in sheaths of the appendages, and around blood vessels and nerves of the subpapillary plexus. These cells are derived from CD34+ stem cells residing in the bone marrow. They produce and store in secretory granules many inflammatory mediators such as histamine, heparin, tryptase, chymase, carboxypeptidase, neutrophil chemotactic factor and eosinophilic chemotactic factor of anaphylaxis. They also release, without storing, growth factors, cytokines and leukotrienes. Giemsa or Leder stains are used to identify mast cells in biopsy specimens. Giemsa stains mast cell granules purple. Leder stains granules red.

Answer 89

Desmosine and isodesmosine Desmosine and isodesmosine are the typical amino acids of elastic fibers. Elastic fibers are comprised of elastin that is wrapped by fibrillin microfibrils. Elastic fibers form a complex meshwork extending from the lamina densa of the dermo-epidermo junction through the dermis. Elastic fibers return the skin to a normal shape after being stretched.

Answer 90

0.4 mm/day Hair grows at an average of 0.4 mm/day. The other options are incorrect.

Answer 91

Lamina fibroreticularis comprises of anchoring fibrils and the elastic microfibrils Lamina fibroreticularis comprises of anchoring fibrils and the elastic microfibrils. Lamina fibroreticularis lies below lamina densa. Blood vessels don't cross the dermal-epidermal junction to reach the epidermis. Basement membrane contain both: 1)Lamina basale which include a.lamina lucida and b.lamina densa( which contain collagene IV & other glycoproteins like laminins,fibronectin etc.) 2)Lamina fibroreticularis contain collagen type III and anchoring fibrils (collagen type VII)

Answer 92

Lamina fibroreticularis comprises of anchoring fibrils and the elastic microfibrils Lamina fibroreticularis comprises of anchoring fibrils and the elastic microfibrils. Lamina fibroreticularis lies below lamina densa. Blood vessels don't cross the dermal-epidermal junction to reach the epidermis. Basement membrane contain both: 1)Lamina basale which include a.lamina lucida and b.lamina densa( which contain collagene IV & other glycoproteins like laminins,fibronectin etc.) 2)Lamina fibroreticularis contain collagen type III and anchoring fibrils (collagen type VII)

Answer 93

Laminin 5 Involvement of Laminin 5 would raise the suspicion for malignancy when found. ~30-40% of cases may have associated malignancy. Patients with antiepiligrin (laminin 5) CP indicated an increased risk of malignancy that approximates that for adults with dermatomyositis. The risk is particularly high in the first year of disease (E-medicine, www.emedicine.com/derm/topic79.htm). Reports of both lung and gastric carcinomas are seen in the literature with some feeling that gastric malignancy is most common.

Answer 94

Respond to chemical stimuli such as hormones Sebaceous glands are androgen-responsive holocrine glands that enlarge at puberty. Meibomian glands of the eyelids are modified sebaceous glands. Sebaceous glands are found everywhere on the skin except the palms and soles. Fordyce�s condition involves free sebaceous glands on the vermillion border of the lips and on the buccal mucosa. Eccrine glands are thermoregulatory structures that respond to cholinergic stimulation.

Answer 95

``` C-polymodal nociceptor class nerves Itch is transmitted primarily by C-polymodal nociceptor class nerves. These are small diameter unmyelinated nerves that carry pain, thermal, mechanical and pruritic stimuli. A-delta fibers carry pain, thermal, mechanical and in some cases pruritic stimuli. A-beta fibers carry light touch and motion stimuli. Parasympathetic post-ganglionic fibers do not contribute to cutaneous pruritus ```

Answer 96

Desmosomes Keratin filaments insert into desmosomes and hemidesmosomes in the basal cell layer and into desmosomes in the layers above. Connexins do not bind keratin filaments. Odland bodies and lamellar granules are synonyms. These are a "membrane bounded organelle, specialized for the storage and secretion various substances (surfactant phospholipids, glycoproteins and acid phosphates) which are arranged in the form of tightly packed, concentric, membrane sheets or lamellae. Has some similar properties to, but is distinct from, a lysosome."

Answer 97

Hours Re-epithelialization begins hours after an injury occurs. Keratinocytes from residual epithelial structures leapfrog each other. One to two days after injury, cells at the wound margin proliferate and begin to migrate into the wound.

Answer 98

TGF-alpha Platelets release PDGF, TGF-alpha and TGF-beta which promote new tissue growth. FGF and IL-1 are released from monocytes as growth factors (monocytes also release PDGF, TGF-alpha and TGF-beta). ADP is released from platelets, but is not functioning as a growth factor. Neutrophil chemotactic factor is released from mast cells and is an inflammatory mediator.

Answer 99

A cessation of mitotic activity in rapidly dividing hair matrix cells Anagen effluvium results from an outside stimulus � most often an antimetabolite, chemotherapeutic drug � inducing an abrupt cessation of hair matrix cell mitotic activity. This process occurs within days to weeks of the stimulus, and is reversible with cessation of the drug therapy.

Answer 100

The melanosomes are positioned after the Golgi apparatus in the secretory pathway. Melanosomes are organelles related to lysosomes and are positioned after the Golgi apparatus in the secretory pathway. Elliptical melanosomes have concentric lamellae and synthesize brown-black eumelanin. Spheroid melanosomes have microvesicular structure and synthesize yellow or red pheomelanin.

Answer 101

on hands/feet Glomus cells are derived from Susquet-Hoyer canals which function to shunt blood from the arterioles to venules and are primarily found on hands and feet. There are two types of glomus tumors, solitary and multiple. The solitary types tend to have paroxysmal pain which can be extreme. Multiple glomus tumors can be a autosomally dominant trait with incomplete penetrance and are less likely to be painful. Both have a predominance on the distal extremities, especially sub-ungual. Two tests are helpful in diagnosing glomus tumors: Hildreth sign - disappearance of pain following application of a tourniquet proximally. Love test - eliciting pain by applying pressure to a precise area with the tip of a pencil.

Answer 102

Follicles develop in a cephalad to caudal direction The first primordial hair follicles form at 9 weeks gestation on the eyebrows, upper lip, and chin. The remaining follicles develop at 4-5 months in a cephalad to caudal direction. New follicles cannot develop in adult skin.

Answer 103

The "spines" seen on pathology are due to desmosomal connections between keratinocytes The "spines" seen on pathology are due to desmosomal connections between keratinocytes, NOT hemidesmosomes. The hemidesmosomes are present in the cells at the base of the basal layer and are part of the connection between the epidermis and basement membrane. Keratin expression continues in the spinous layer. Keratins 1/10 are synthesized, not keratins 5/14. Keratin 5/14, however, is still present. Keratohyaline granules are typically seen in the granular layer.

Answer 104

Type III Collagen Type III collagen is found in the fetal skin. It is also present in the gastrointestinal tract, blood vessels, and the basement membrane. A defect in this collagen results in the Ehlers-Danlos, vascular type.

Answer 105

Desmocollin 1 Sneddon- Wilkinson disease, also known as sub-corneal pustular dermatosis is due to a defect in desmocollin 1. Desmoglein 1 defect is seen in pemphigus foliaceous and staph scalded skin syndrome. Desmoglein 3 defect is seen in pemphigus vulgaris and intraepidermal neutrophilic IgA dermatosis. BPAg1 is seen in paraneoplastic pemphigus and bullous pemphigoid. BPAg2 is seen in bullous pemphigoid, cicatricial mucous membrane pemphigoid and linear IgA disease.

Answer 106

Contain squalene Odland bodies mediate stratum corneum adhesion in conjunction with FILAGGRIN. They discharge their contents into the extracellular space at the junction of the granular and horny layers establish a barrier to water loss. They are first found intracellularly in upper level keratinocytes and contain ceramides not squalene.

Answer 107

1st trimester Hair follicles begin in the third month of fetal life as a downgrowth of cells from the epidermis (3rd month=12th week=1st trimester).

Answer 108

Type VII Collagen Anchoring fibrils are made of Type VII collegen. Anchoring plaques are made of Type IV collagen, and interact with a network of Type I And Type III collagen fibers in the dermis.

Answer 109

24 weeks At 24 weeks, all the layers of the mature epidermis can be identified, and the epidermis is keratinized.

Answer 110

In white skin the melanosomes form groups within the secondary lysosomes Melanocytes of dark skin synthesize melanosomes larger than those produced in light skin. The number of melanocytes in the epidermis is the same, regardless of the person's race or color: it is the number and size of the melanosomes or pigment granules, continuously synthesized by these melanocytes, that determine differences in skin color. The size of th melanosome is the principle factor in determining how the melanosomes will be distributed within the keratinocytes. The larger the melanosomes of dark skin are individually dispersed within the cytoplasm of keratinocytes: smaller melanosomes of light skin are packaged in membrane-bound complexes within keratinocytes. Eumelanin is in dark oval melanosomes found in black hair

Answer 111

``` Are secretory granules with features of lysosomes Odland bodies (AKA lamellar granules) are lamellated bodies containing ceramide, are found intercellularly in upper level keratinocytes; they discharge contents into the extracellular space at the junction of the granular and horny layers, establish a barrier to water loss, and with filaggrin mediate stratum corneum adhesion. Recent studies suggest that they are a type of secretory granule with features of lysosomes. (They contain lamellar-body-derived enzymes that are important in desquamation.) ```

Answer 112

Macrophages Macrophages are the most important cell for wound healing. They secrete TFGs, cytokinas, IL-1, TNF, and PDGF. Neutropenic or lymphopenic patients do not have impaired wound healing, whereas macrophage-deficient (quantity or function) patients heal poorly. Neutrophils however are the first cell type to flood the wound during phage I of inflammation (within first 6-8 hours); this movement is facilitated by TGF-beta. Fibroblasts migrate into the wound by stage II (granulation) where they produced glycosaminoglycans and fibronectin.

Answer 113

Type III collagen Type 1 collagen is the most prevalent collagen in skin, accounting for 80% or more of the total collagen in the adult dermis. Type III collagen is the next most predominant collagen in human dermis, accounting for approximately 10%. Type IV collagen is found in basement membranes. Type VII collagen is found in human dermis as anchoring fibrils. Type XVII collagen, also known as BPAG2, is an important transmembrane protein in the basement membrane zone.

Answer 114

Copper Tyrosinase is a copper containing enzyme that is responsible for the conversion fo tyrosine to DOPA and DOPA to DOPAquinone.

Answer 115

Sebaceous glands found on the eyelids Sebaceous glands enlarge at puberty in response to increased levels of androgens. They are holocrine glands. Meibomian glands are modified sebaceous glands found in the eyelids. Free sebaceous glands not associated with hairs are found in the nipple and areola and are called Montgomery�s tubercles. Fordyce�s condition involves free sebaceous glands on the vermillion border of the lips and on the buccal mucosa. Sebaceous glands are found everywhere on the skin except the palms and soles.

Answer 116

During the 2nd week of wound healing Wound healing tends to be a predictable process that begins initially with the inflammatory stage. During this stage, clot formation occurs. This is the initial step in wound healing. Platelets, neutrophils and macrophages all migrate to the wound and secrete many mediators of wound healing. Epithelialization then begins hours after injury. This is followed by granulation tissue formation (four days after injury) and angiogenesis (first week of repair). Wound contraction ensues during the second week of healing.

Answer 117

Found on the vermillion border of the lips 3 Located in the dermal papillae of digital skin Krause end bulbs are mucocutaneous receptors found on the glans penis, clitoris, labia minora, perianal area, and vermillion border of the lips. Papillary nerve endings are free nerve endings found at the orifice of the hair follicle and particularly sensitive to cold. Meissner's corpuscles are ovoid, elongated mechanoreceptors located in the dermal papillae of digital skin that detect touch and light pressure. Pacinian (Vater-Pacini) corpuscles exist in the deep dermis and within the subcutis in weight-bearing sites and function as adapting mechanoreceptors that respond to vibrational stimuli.

Answer 118

1 and 7 Retinoids upregulate the transcription of collagens one and seven thereby strengthening the dermis.

Answer 119

Birt-Hogg-Dube Syndrome Fibrofolliculomas are associated with Birt-Hogg-Dube Syndrome and not in the other answer choices.

Answer 120

17 Acid keratins are expressed on chromosome 17 and basic keratins on chromosome 12. The other listed options do not have active keratin functions.

Answer 121

Run parallel in bands within the reticular dermis Elaunin fibers are elastic fibers that have less elastin and more fibrillin and run parallel in thin bands within the reticular dermis. Oxytalin fibers contain no elastin and run perpendicular from the dermo-epidermal junction within the superficial papillary dermis. Elastic fibers turn over slowly in the skin, and are damaged by ultraviolet radiation.

Answer 122

Paraneoplastic pemphigus Paraneoplastic pemphigus and drug-induced pemphigus demonstrate direct immunofluorescence staining of the intercellular space and the BMZ, in combination. Anti-epiligrin pemphigoid demonstrates BMZ staining (dermal staining on salt-split skin). Pemphigus vegetans, pemphigus foliaceous, and IgA pemphigus all show intercellular space deposition without staining of the BMZ.

Answer 123

Secretions are initially odorless Apocrine glands are tubular glands that demonstrate decapitation secretion. Like eccrine glands, the ducts are composed of three segments: intraepidermal duct, intradermal duct and secrectory portion. The duct usually leads to a pilosebaceous follicle above the entrance of the sebaceous duct. They are found in the axillae, anogenital region, external ear canal (ceruminous glands), in the eyelids (Mollï¿½s glands) and in the breast (mammary glands). These glands are functional starting at puberty. The initial secretions are odorless with the odor being derived from C6 ï¿½ C11 acids. The most abundant being 3-methyl-2-hexenoic acid.

Answer 124

Modified sebaceous glands Meibomian glands of the eyelids are modified sebaceous glands. Sebaceous glands are found everywhere on the skin except the palms and soles. Montgomery's areolar tubercles consist of several sebaceous lobules feeding into a lactiferous duct. Ceruminous glands are apocrine glands of the external ear canal. Apocrine glands in the eyelids are Moll's glands.

Answer 125

Integrin Junctional epidermolysis bullosa with pyloric atresia involves a defect in the b4 subunit of the a6b4 integrin. The expression of this protein is limited to the basal layer of the epidermis. This integrin is a transmembrane protein that coordinates a link between the intermediate filaments (keratins) and the extracellular matrix of the basement membrane. The b4 domain mediates an interaction with both plectin and BP180; its absence prevents hemidesmosomal assembly.

Answer 126

Plakoglobin Plakoglobin is an example of an armadillo protein, which links the cytoskeleton associated linking proteins (such as plakins in the case of intermediate filaments and alpha-catenin in the case of actin) to the transmembrane adhesion molecules, termed cadherins. E-cadherin and desmocollin are examples of cadherins. Periplakin and envoplakin are examples of plakin linking proteins.

Answer 127

Elastin fibers make up 4% of dry weight of the skin, forming a complex meshwork extending from lamina densa of the dermoepidermal junction through the dermis and into the hypodermis. Elastins help return the skin to the normal configuration after being stretched. Elastic fibers are 90% elastin wrapped by fibrillin microfibrils. Fibrillin is mutated in Marfan syndrome. The typical amino acids found in elastic fibers are desmosine and isodesmosine. Elastic fibers turn over slowly in the skin and are damaged by ultraviolet radiation.

Answer 128

Protein A northern blot identifies RNA and a southern blot identifies DNA.

Answer 129

Dapsone Dapsone may be used to treat patients with drug induced linear IgA bullous dermatosis which persist after the offending medication has been discontinued. The other medications listed are rare causes of drug induced linear IgA bullous dermatosis and so should not be used for treatment.

Answer 130

Cystathione synthase Homocystinuria is caused by a mutation in cystathione synthase. The main skin findings are a malar flush, livedo reticularis and leg ulcerations. A characteristic eye finding is the downward displacement of the lens. The other options are involved in abnormalities associated with Ehlers-Danlos syndrome. Lysyl hydroxylase is deficient in Kyphoscoliosis type of EDS. Tenascin X is involves in ~3% of Classical type EDS cases. Dermatosparaxis type EDS has recessive mutations in the type I collagen N-peptidase gene.

Answer 131

Buschke Ollendorf LEMD3 or MAN1 is mutated in Buschke-Ollendorf syndrome. Common skin findings include dermatofibrofibrosis lenticularis disseminata. The radiographic finding commonly seen is osteopoikilosis. The gene defect was recently described as MAN1/LEMD3, a gene encoding for a nuclear membrane protein. Albright Hereditary Osteodystrophy is caused by inactivation of GNAS1, Goltz is an x-linked dominant condition with unknown pathogenesis, McCune-Albright syndrome is caused by an activation of GNAS1. Menke's Syndrome is caused by a defect in ATP7A/MKN on Xq13.

Answer 132

Abnormal crosslinking of collagen Excess homocystine leads to abnormal crosslinking of collagen, with only ~1/3 of crosslinking activity compared to normal controls (OMIM 236200). The other listed findings are not features of homocystinuria, though hypopigmentation can be a featur

Answer 133

Palms Apocrine glands operate by decapitation secretion and are activated by epinephrine and norepinephrine. They are located in a few distinct areas of the body, which include axillae, anogenital region, Moll�s glands of the eyelids, mammary glands of the breast and the ceruminous glands of the external auditory canal.

Answer 134

Glycogen In week 7 of embryogenesis the surface ectoderm produces two layers. The external layer is the periderm which contains glycogen and gives rise to the stratum corneum by week 21. The other layer is the stratum germinativum.

Answer 135

Pemphigus foliaceus The antigen implicated in pemphigus foliaceus is Desmoglein 1. Desmoglein 1 is targeted in bullous impetigo, but this is an infectious condition, not an autoimmune disease. The antigen in dermatitis herpetiformis is transglutaminase 3. The antigens for both bullous pemphigoid and pemphigoid gestationis are BPAG1 and BPAG2.

Answer 136

Stimulus induces the abrupt cessation of miotic activity in the rapidly dividing hair matrix cells It is frequently seen following administration of cancer chemotherapeutic agents. Stimulus induces the abrupt cessation of mitotic activity in the rapidly dividing hair matrix cells. Occurs within days to weeks following exposure to the inciting agent and is entirely reversible. Frequent causes include antimetabolites, alkylating agents, mitotic inhibitors, thallium, boron. Frequent causes include doxorubicin, nitrosureas and cyclophosphamide.

Answer 137

IL-2 Keratinocytes have been shown to secrete all of the above cytokines, except IL-2, IL-4, and IFN-gamma.

Answer 138

Buschke-Ollendorf syndrome Cutis laxa results from decreased desmosine and lysyl oxidase and demonstrates fragmentation and loss of elastic fibers. Marfan's sydnrome results from decreased fibrillin I and demonstrates fragmentation of elastic fibers. Pseudoxanthoma elasticum demonstrates increased glycosaminoglycans on elastic fibers and the accumulation of fragmented and calcified elastic fibers. Anetoderma has decreased desmosine and demonstrates loss and fragmentation of elastic fibers. Buschke-Ollendorf syndrome exhibits increased desmosine and an increased amount of thickened elastic fibers.

Answer 139

Holocrine Sebaceous glands are associated with holocrine type secretion (release by rupture of the plasma membrane). Apocrine is used to describe decapitation secretion for the cell (as seen in apocrine glands). Merocrine secretions are characterized by exocytosis (salivary glands as well as some eccrine and apocrine glands). Exocrine and Endocrine describe glands that secrete directly into the extracellular environment and directly into the blood stream respectively.

Answer 140

Demonstrate decapitation secretion Apocrine glands show decapitation secretion. Like eccrine glands, apocrine glands are composed of three segments, the intraepidermal duct, the intradermal duct, and the secretory portion. The duct of the apocrine gland usually leads to a pilosebaceous follicle above the entrance of the sebaceous duct. Apocrine glands are found in the axillae, anogenital region, external ear canal (ceruminous glands), in the eyelids (Moll�s glands), and in the breast (mammary glands). Apocrine glans are functional only at puberty. Their initial secretion is odorless. Hidradenitis suppuritiva is a disease involving apocrine glands.

Answer 141

CK20 Cytokeratin (CK) 20 is a reliable marker for Merkel cells. CD20 is a marker for B-cells and CD3 is a T-cell marker. HMB-45 is used in staining for immature melanosomes and is reactive in melanoma. CD34 is used to stain dermatofibrosarcoma protuberans.

Answer 142

Junctional epidermolysis bullosa with pyloric atresia JEB with pyloric atresia and ocular cicatricial pemphigoid both have mutations in Beta4integrin. Herlitz type JEB is due to laminin 5. Recessive and dominant dystrophic EB is due to COL17A1 (type VII collagen). JEB with myotonic dystrophy is due to plectin.

Answer 143

Regulate water-binding capacity The function of glycosaminoglycans/proteoglycans in the dermis is to regulate water-binding capacity. The other listed options are not functions of glycosaminoglycans / proteoglycans.

Answer 144

Inner root sheath The inner root sheath stains red because it contains citrulline. The cortex and medulla along with the cuticle make up the hair shaft. The outer root sheath is the most peripheral cellular structure. The glassy vitreous layer is the basement zone equivalent of hair and is the outermost layer.

Answer 145

keratinocytes S100 is sensitive for melanocytes and melanoma, but not specific as it also stains langerhans cells, eccrine cells, schwann cell, adipocytes, and chondrocytes. It is negative in keratinocytes and can help discriminate melanoma from pagetoid bowens or spindle cell squamous cell carcinoma.

Answer 146

Calcium The desmosomal connections in the epidermis are calcium dependent. The other options are not required for these connections.

Answer 147

Holocrine Sebaceous glands exhibit holocrine secretion, whereby the sebocytes disintegrate in transit to the gland center, releasing their sebum contents. Merocrine secretion refers to the formation of intracellular secretory vesicles that translocate to the apical cell surface for secretion. Apocrine secretion refers to the process whereby secretory contents are packaged using the apical cell membrane, and 'pinched off' to achieve secretion.

Answer 148

Proline and hydroxyproline Collagen fibers provide tensile strength to the skin and allow it to serve as a protective organ against the external environment. Collagen makes up 80% of the dry weight of the dermis. The structure of collagen is comprised of three alpha chains arranged into a triple helix. The repeating amino acid triplets of the triple helix of collagen are most often Glycine-Proline-Hydroxyproline.

Answer 149

Telogen effluvium All of the listed stressors can induce telogen effluvium. Other causes include traction and some drug exposures. Usually will only involve up to 50% of scalp hairs and will resolve within 2-3 months.

Answer 150

Macrophage The macrophage is required for wound healing. Without macrophages, there is no healing. Macrophages debride tissue through phagocytosis and digestion of organisms, tissue debris and effete PMN's. They secrete collagenase and secrete growth factors that facilitate transition from inflammation to repair.

Answer 151

Ectoderm As implied by the root 'ecto', a prefix meaning "outer", the keratinocytes of the epidermis are derived from the ectoderm. The other layers do contribute cell populations that are present in the skin.

Answer 152

Profilaggrin and loricrin Keratohyalin granules are found in the stratum granulosum (the granular layer), and contain the proteins profilaggrin and loricrin. Profilaggrin is converted to filaggrin during the transformation of the granular layer to the cornified layer. This is a calcium-dependent process. Loricrin comprises 75% of the cornified envelope�s mass.

Answer 153

Vater-Pacini corpuscle Vater-Pacini corpuscles sense deep touch and vibration. Merkel cells are slow adapting type I mechanoreceptors found among basal keratinocytes. Meissner corpuscles are found in the dermal papilla, especially in the palms and soles. Krase end-bulbs are mucocutaneous end-organs found on the glans penis, prepuce, clitoris, labia minora, and vermillion border of the lip.

Answer 154

Plakin BP230 is a member of the plakin family and is homologous to desmoplakin and is intracellular. It attaches intermediate filaments to hemidesmosomal plaque. The remaining options are not part of the plakin family.

Answer 155

MC1-R MC1-R is the receptor that binds alpha-MSH, and ACTH\>alpha-MSH. Defects in this receptor will produce a phenotype including red hair. Agouti is not involved in this process. Agouti describes the banding of hairs seen in some mammals such as dogs, foxes, and mice, which is due to alternating production of eumelanin and pheomelanin occurs. This has not been described in humans (Bolognia, p942). The hairless gene is associated with alopecia totalis. C-kit mutations are associated with piebaldism and urticaria pigmentosa. Tyrosinase defects are associated with Type I Oculocutaneous albinism.

Answer 156

lichen planopilaris Lichen planopilaris is a chronic, scarring condition that results in permanent loss of hair and destruction of the hair follicles. Defect in lipid metabolism and peroxisome biogenesis may contribute to LPP pathogenesis. Medications that act as PPAR agonists, such as pioglitazone, may have a role in controlling the progression of this disease. (Karnik P, et al. (2009) Hair follicle stem cell-specific PPAR deletion causes scarring alopecia. J Invest Dermatol 129:1243â57)

Answer 157

Mononuclear phagocytic cells The mononuclear phagocytic cell includes monocytes, macrophages and dermal dendrocytes. All phagocytic skin macrophages express CD11c and CD6. Fibroblasts do not produce a CD marker. Mast cells are derived from bone marrow-residing CD34+ stem cells. They do not produce CD11c or CD6.

Answer 158

Plectin Anchoring filaments exist within the lamina lucida. They are primarily comprised of laminin 5 and BP180. Laminin 5 is a cross-shaped assembly of 3 classes of polypeptides, a, b, g. The anchoring filaments function as a structural network to which other proteins attach, and they function as signaling molecules that transmit morphogenetic information to transmembrane proteins of the basal cell layer (such as the integrins). Laminin 5 is also called epiligrin and binds to the a6b4 integrin at the hemidesmosome.

Answer 159

Collagen V Classical types of Ehrlers-Danlos are manifested by varying degrees of hyperextensible skin, easy bruising, wide, atrophic scars, and hypermobile joints. The genetic defect is in Collagen V. Elastin is mutated in Cutis Laxa. ABCC6 is defective in Pseudoxanthoma elasticum. Cystathionine beta-synthase is mutated in homocystinuria.

Answer 160

Keratins 6 and 16 Keratins 6 and 16 are upregulated in hyperproliferative keratinocytes, outer root sheath, and oral epithelium. A defect in these keratins may result in pachyonychia congenita.

Answer 161

Substance P Substance P is a neuromediator that binds the tachykinin receptor. It is released upon stimulation of sensory nerve fibers. It has numerous cutaneous functions, including development of skin edema, erythema, and pruritus, upregulation of adhesion molecule expression, release of proinflammatory mediators, etc. Capsaicin causes release of substance P. This has been utilized pharmacologically in conditions such as zoster, in which consistent application of capsaicin leads to depletion of substance P, which in turn can help to reduce/eliminate post-herpetic neuralgia. The other answer choices are also neuromediators that are involved in cutaneous inflammation, but their release is not induced by capsaicin.

Answer 162

Pityrosporum ovale All the above bacteria and fungi are found within sebaceous glands; the Malasssezia spp. and P. ovale are found within the acroinfundibulum, S. epidermidis is found within the midinfundibulum, and Propionibacterium spp. deep within the follicle.

Answer 163

It is the widest diameter of the hair bulb The critical line of Auber is at the widest diameter fo the hair bulb. Below this line, the bulk of mitotic activity that gives rise to the hair and the inner root sheath occurs. The erector pili muscle inserts in the isthmus region of the follicle. Keratinization first occurs above this line.

Answer 164

Adrenocorticotropic hormone Both alpha-MSH and ACTH are cleavage products of proopiomelanocortin (POMC).

Answer 165

Susquet-Hoyer canal Glomus cells are vascular smooth muscle cells derived from the arterial portion of the glomus body, or the Sucquet-Hoyer canal, which is an arteriovenous shunt in the dermis that contributes to temperature regulation. Glomus are found primarily on the palms and soles and function to allow the rapid shunting of blood from the arteioles to venules. Disease processes involving glomus cells include glomus tumor and glomangioma.

Answer 166

Flegel's Flegel's disease has decreased or absent lamellar granules. AKA hyperkeratosis lenticularis perstans, this is a rare, possibly AD disorder with multiple disc-like keratotic papules predominenty on the distal extremities and feet of older individuals (Bolognia, p 1714).

Answer 167

All of these options are correct A scar has 5% strength at 1 week, 20% at 3 weeks and 70% at 1 year. It will never recover strength to the level of pre-injury.

Answer 168

Keratin 20 Keratin 20 is reliable immunohistochemical markers for Merkel cells as it is restricted to these cells in the skin. Keratin 7 can be used as a marker for Paget's Disease. S-100 is frequently used to stain neural cells and melanocytes. Factor XIIIa can be used to differentiate a dermatofibroma from dermatofibroma sarcoma pertuberans (positive in DF; negative in DFSP). LYVE-1 is a marker for lymphatics.

Answer 169

Beta-catenin Beta-catenin is the downstream mediator of WNT signaling. Through a series of signals, WNT proteins inhibit the degradation of beta-catenin in the cytoplasm. After being translocated to the nucleus, beta-catenin then forms a complex with LEF/TCF transcription factors, which ultimately results in expression of downstream genes. Activation of this pathway is necessary for epithelium to have the potential to develop a hair follicle.

Answer 170

Holocrine secretion Sebaceous glands form a lipid-rich substance called sebum and are usually associated with a hair follicle. They secrete sebum by means of holocrine secretion which means that they exude lipids by disintegration of entire sebocytes. Sebum contains numerous lipids including cholesterol, cholesterol esters, triglycerides, squalene, and wax esters. Sebaceous glands are regulated by androgens and the activity can be regulated by retinoids.

Answer 171

Epidermal side The image shown is bullous pemphigoid. On salt split skin DIF exams, deposits are seen on the epidermal side of the split. If dermal deposits are seen, epidermolysis bullosa acquisita or anti-epiligrin pemphigoid are potential diagnoses.

Answer 172

EMA Sebaceous carcinomas stain positive for EMA. The other answer choices are incorrect as they do not stain positive in sebaceous carcinoma.

GALDERMA 1 BASIC SCIENCE Flashcards

(199 cards)