Chapter 1: SKin: Basic Structure And Function

Question 1

What are the layers of the skin?

Answer 1

Epidermis, Dermis and subcutaneous fat (panniculus)

Question 2

The thickest layer of epidermis is found where

Answer 2

Palms and soles (1.5mm)

Question 3

Thinnest layer of epidermis is found where

Answer 3

Eyelids 0.1mm

Question 4

What’s do you call the layer of nonkeratinizing cuboidal cells covering the fetus during the first week of life?

Answer 4

Periderm

Question 5

Adnexal structures, particularly the eccrine and follicles originate from where?

Answer 5

Downgrowths from the developing epidermis

Question 6

Where do adnexal structures first appear?

Answer 6

Cephalic portion of the fetus then caudal

Question 7

What cells can be found in the adult epidermis

Answer 7

Keratinocyttes, Melanocytes, langerhands cells and Merkel cells (basal layer at palms and soles)

Question 8

Stains for Merkel cells

Answer 8

Polyclonal keratin immunisation and monoclonal immunostain for keratin 20

Question 9

Origin of keratinocytes

Answer 9

Ectoderm

Question 10

Disease condition associated with mutation in the genes for keratin 5 and 14?

Answer 10

Epidermolysis bullosa simplex

Question 11

Disease conditions associated with Keratin 1 and 10 mutations

Answer 11

Epidermolytic hyperkeratosis

Question 12

Layers of the epidermis

Answer 12

Stratum corneum (horny layer)
Stratum granulosum (granular layer)
Stratum spinosum (prickle layer or malpighian)
Stratum germinativum (basal layer)

Question 13

What layer is formed when skin scratched or rub and which layers thicken?

Answer 13

Stratum lucidum is formed while the malpighian and granular layers thicken

Question 14

Sites rich in stem cells

Answer 14

Reste ridges especially on palmoplantar skin, as well as the hair bulge

Question 15

Abnormal keratinization manifests as?

Answer 15

Parakeratosis (retained nuclei)
Corps ronds (round, clear to pink keratinized cells)
Grains (elongated, basophilic keratinized cells)

Question 16

Desmosomal adhesion depends on what?

Answer 16

Cadherin

Question 17

What process results in the promotion of stratification and differentiation of keratinocytes through the down regulation of RAS-RAF pathway?

Answer 17

Binding of desmoglein 1 to protein erbin

Question 18

Where does the conversion of profilaggrin to filagrin occur?

Answer 18

Granular layer (Stratum granulosum)

Question 19

Where are Melanocytes derived from? And when can it be found in the fetal epidermis?

Answer 19

Neural crest, 8th week of development

Question 20

In the sun protected trunk epidermis what is the melanocyte to keratinocyte ratio?

Answer 20

1:10

Question 21

what percentage of cells do langerhans cells constitute to?

Answer 21

3%-5%

Question 22

Where can you find the highest density of langerhans cells?

Answer 22

Oral mucosa in the vestibular region

Question 23

Where can you find the lowest density of langerhans cells

Answer 23

Sublingual region

Question 24

Stains for langerhans cells

Answer 24

Gold chloride
CD1a
S-100

Question 25

What cytokine is by macrophages when the skin is irradiated with UVB?

Answer 25

IL-10

Question 26

Components of the DEJ?

Answer 26

Plasma membrane of basal cells and hemidesmosomes Lamina Lucida Lamina Densa Basal Lamina

Question 28

Major collagen of basal lamina

Answer 28

Collagen 4

Question 29

What are the major hemidesmosomal proteins in the basal lamina

Answer 29

BP180 and BP 230

Question 30

What permits exchange of cells and fluids between the epidermis and dermis?

Answer 30

BMZ

Question 31

Major component of laminate lucida/lamina densa

Answer 31

Laminin 5 (Laminin -332)

Question 32

Eccrine, apocrine, ducts and pilosebaceous units originate from where?

Answer 32

Ectoderm, downgrowths of the epidermis

Question 33

What transducer is critical in hair development through hedgehog signaling?

Answer 33

Smoothened

Question 34

What is the intraepidermal duct which opens directly onto the skin surface?

Answer 34

Acrosyringium from dermal duct cells

Question 35

T/F Eccrine sweat units are found at virtually all skin sites

Answer 35

True

Question 36

T/F Sweat is similar in composition to plasma

Answer 36

True

Question 37

T/F Sweat secretion is mediated by cholinergic innervation

Answer 37

True

Question 38

T/F Apoccrine secretion is mediated by cholinergic innervation

Answer 38

False, appocrine secretion is mediated by addrenergic innervation and by circulating catecholamines of adrenomedullary origin

Question 39

Sites of appocrine units

Answer 39

Axillaire, anogenital region, external auditory canal, eyelids

Question 40

Growth phases

Answer 40

Anagen (3-5 years) Cartagena (2 weeks) Telogen ( 3-5 Months)

Question 41

Areas where sebaceous glands are most abundant

Answer 41

Face and scalp

Question 42

How many months would it take to replace a complete nail plate? To replace a great toe nail?

Answer 42

Nail plate, 4-6 months Great toenail, 12-18 months

Question 43

Amino acids found in collagen?

Answer 43

Hydroxyserine and hydroxy proline and glycine

Question 44

Major collagen of the dermis?

Answer 44

Type 1 collagen

Question 45

What muccopolysaccaride comprises the ground substance of the dermis?

Answer 45

chondroitin sulfate and dermatan sulfate

Question 46

Where can you find the postcapillary veinules

Answer 46

Subpapillary plexus or upper horizontal network att the junction of the papillary and reticular dermis

Question 47

Specialized smooth muscle which serve to shunt blood and regulate temperature found between the digits and lateral margins of palms and soles

Answer 47

Glomus bodies

Question 48

Touch and pressure sense is mediated by?

Answer 48

Meissner corpuscles in the dermal papillae

Question 49

Cells that resemble fried eggs in histologie sections and plays an important role in immediate type sensitivity, contact allergy and fibrosis

Answer 49

Mast Cells

Question 50

Stains for mast cells

Answer 50

Toluidine blue Methelyn blue Leader ASD Chloracetase

Question 51

Hormone produced by lipocytes which regulate body weight and influences how we react to flavor in food

Answer 51

Leptin