skin

Question 1

what are the general tissue types for epidermis, dermis and hypodermis?

Answer 1

epidermis- stratified squamous epithelium
dermis- CT
hypodermis- adipose

Question 2

what are the embryologic origins of the epidermis, dermis?

Answer 2

epidermis- ectoderm

dermis- mesoderm

Question 3

where are the blood vessels, nerves, appendages found?

Answer 3

dermis

Question 4

where is thick skin found?

Answer 4

fingertips, palms, soles

Question 5

what are the epidermal layers in thick skin?

Answer 5

basale
spinosum
granulosum
lucidium
corneum

Question 6

what are the epidermal layers in thin skin?

Answer 6

basale
spinosum
granulosum
corneum

Question 7

are hair follicles present in thick skin?

Answer 7

not present in thick skin, only in thin skin

Question 8

what are the 2 types of sweat glands? what do they secrete?

Answer 8

eccrine- clear

apocrine- cloudy/odorous

Question 9

what are the cell types in the epidermis from most to least numerous? roles?

Answer 9

keratinocytes- produce keratin
melanocytes- produce melanin
langerhan cells- APCs
merkel cells - nerve endings

Question 10

which layers make up the malpighian layer?

Answer 10

stratum basale and spinosum

Question 11

what is meant by “germinativum”?

Answer 11

ability to amplify, divide and differentiate

Question 12

what causes pemphigus?

Answer 12

autoimmune destruction of desmoglein (desmosome attachments), results in erosions/ulcerations

Question 13

what is contained in the keratohylain granules?

Answer 13

profilaggrin, loracrin, involucrin, cornifin – all in the stratum granulosum

Question 14

what are lamellar bodies?

Answer 14

impermeable, lipid-containing membrane that serves as a water barrier and is required for correct skin barrier function

Question 15

what composes the stratum corneum?

Answer 15

stacks of a nucleate corneocytes surrounded by lipid-rich membranes , contain keratin and filaggrin

Question 16

what are the substances that keratinocytes produce? (5)

Answer 16

cytokines, prostaglandins, antioxidants, platelet/fibroblast stimulating factors, vit D3

Question 17

what is ichthyosis?

Answer 17

genetic defect in the ability to shed stratum corneum

Question 18

what layers are SCC/BCC derived?

Answer 18

BCC- S. basale
SCC- s. spinosum
(keratinocyte carcinomas)

Question 19

what is the embryologic origin of melanocytes?

Answer 19

neural crest cells

Question 20

what is the shape of melanocytes?

Answer 20

with special stains, appear as dendritic cells. on H+E, look like a “hole”

Question 21

where are melanocytes located?

Answer 21

stratum basale

Question 22

how is melanin formed?

Answer 22

from tyrosine under the action of tyrosinase (tyrosine –> dihydroxyphenylalanine –> dopoaquinone)

Question 23

what are the 2 forms of melanin?

Answer 23

eumelanin- brown/black

phaeomelanin- yellow/red

Question 24

what causes albanism?

Answer 24

tyrosinase def

Question 25

how is melanin secreted?

Answer 25

from melanocytes, in melanosomes via cytocrine secretion

Question 26

what is cytocrine secretion?

Answer 26

part is bitten off and engulfed by adjacent cells

Question 27

what influences the actions of our melanocytes?

Answer 27

everyone has the same number of melanocytes, their production of melanin is influenced by genetics, medications, exposures

Question 28

what are the actions of melanin?

Answer 28

absorb UV light, protect DNA in basal cells

Question 29

what is the result of UV tanning?

Answer 29

increased eumelanin in epidermis, darkening of melanosomes, photoprotection

Question 30

where are langerhan cells derived?

Answer 30

bone marrow

Question 31

what is the function of langerhan cells?

Answer 31

APCs, capture antigen, move to dermis then LN, clone of sensitized T-cells produced

Question 32

what occurs with re-exposure in the skin?

Answer 32

inflammatory response (delayed hypersensitivity), acute contact dermatitis

Question 33

what is contained in Merkel cells?

Answer 33

neurosecretory granules

Question 34

what is the basement membrane of skin?

Answer 34

hemidesmosomes attach basal cell to dermis

Question 35

what is epidermolysis bullosa?

Answer 35

seen in children with defect in basement membrane, will have blistering

Question 36

what composes the dermis? (4)

Answer 36

collagen (I and III), elastic fibers, GAGs, resident cells (FAMM)

Question 37

where is the superficial plexus of blood vessels located? deep?

Answer 37

superficial- in the dermal ridges | deep- subcutaneous tissue

Question 38

which glands are attached to hair follicle?

Answer 38

apocrine glands and sebaceous glands

Question 39

what composes the "pilosebaceous unit"?

Answer 39

hair follicle, sebaceous gland, apocrine gland

Question 40

what are the phases of hair growth?

Answer 40

anagen catagen telogen

Question 41

what stimulates sebaceous glands? inhibits?

Answer 41

androgens; estrogens

Question 42

where are sebaceous glands most prominent?

Answer 42

on the face

Question 43

describe eecrine glands

Answer 43

produce isotonic secretion, merocrine secretion, opens to skin surface

Question 44

how do eecrine glands look on H+E (ducts and secretory unit)?

Answer 44

secretory- light | ducts- dark

Question 45

define the types of secretion for sebaceous/eecrine/apocrine glands

Answer 45

sebaceous- holocrine eecrine- merocrine aporcrine-merocrine

Question 46

which sweat glands are reap for odor?

Answer 46

apocrine

Question 47

what are the 2 types of nerves in the skin?

Answer 47

meissners and pacinian

Question 48

where are meissners's corpuscles located? function?

Answer 48

dermal ridges | light touch

Question 49

where are pacinian's corpuscles located? function?

Answer 49

hypodermis | deep pressure, vibratory sense

Question 50

what substance composes the nail plate?

Answer 50

keratin

Question 51

from where are langerhan's cells derived?

Answer 51

bone marrow- derived from monocytes

Question 52

what directly underlies the stratum basale? what attaches it to this structure?

Answer 52

basement membrane by hemidesmosomes

Question 53

what skin layers make up the hair complex?

Answer 53

epidermis- external root sheath basal lamina- glassy membrane papillary dermis- connective tissue sheath

Question 54

what are also called "Prickle Cells"?

Answer 54

cells in the s. spinosum

Question 55

what is the most common cell type in the dermis?

Answer 55

fibroblasts, that secrete the most common substance collagen (I and III)

Question 56

what produces Vit D3?

Answer 56

interaction of cholesterol and UVB rays

Question 57

what are Bibeck granules?

Answer 57

look like tennis rackets inside langerhan cells

Question 58

what produces bullous pemphigoid?

Answer 58

antibodies against basement membrane

Question 59

what produces pemphigus vulgaris?

Answer 59

antibodies against desmosomes

Question 60

what type of glands might produce pheromones?

Answer 60

apocrine (not essential to humans)

Question 61

what is the epinychium? hyponychium?

Answer 61

epi- proximal junction of nail | hypo- distal junction of nail, where free end meets fingertip

Question 62

what underlies the nail plate?

Answer 62

dermis deep then nail bed more superficial

Question 63

where are pacinian corpuscles m/c seen?

Answer 63

palms/soles