Histology of the Skin

Question 1

what are the functions of the skin?

Answer 1

protection
regulate body temp 
reception
absorption
excretion

Question 2

what kind of epithelium does the epidermis contain?

Answer 2

stratified squamous keratinized epithelium

Question 3

what does the dermis contain?

Answer 3

superifcial layer: loose CT

deep layer: denser, irregular collagenous CT

Question 4

what are the cells of the epidermis classified as?

Answer 4

keratinocytes

nonkeratinocytes

Question 5

how long does it take for new cells to migrate from the basal layer of the epidermis to the surface of the skin?

Answer 5

20-30 days

Question 6

Name the types of non-keratinocytes.

Answer 6

Langerhans cells
merkel cells
melanocytes

Question 7

what are langerhans cells? and where are they derived from?

Answer 7

are defense cells (APC and dendritic cells) tht are derived from precursors in teh bone marrow –> bloodstream –> differentiate into langerhans cells in the epidermis

Question 8

where are langerhans cells found in the epidermis?

Answer 8

all layers of epidermis, but mainly in stratum spinosum and superficial dermis

Question 9

Which cell type has birbeck granules?

Answer 9

langerhans cells

Question 10

what does the integument consist of?

Answer 10

skin
sweat glands
sebaceous glands
hair
nails

Question 11

where are merkel cells found?

Answer 11

stratum basale

Question 12

which cell type is responsible for fine discriminative touch for detecting shape and texture of objects?

Answer 12

merkel cells

Question 13

where are melanocytes derived from?

Answer 13

neural crest cells

Question 14

where are melanocytes located?

Answer 14

stratum basale and superficial dermis

Question 15

what is the precursor to melanin?

Answer 15

tyrosine

Question 16

how does the # of melanocytes vary amount races?

Answer 16

total # of melanocytes is the same in all races

it is the pigmentation that changes

Question 17

how does the number of melanocytes vary in different areas of the skin?

Answer 17

varies in different areas of teh skin

Question 18

how does pigmentation of skin occur?

Answer 18

depends on tyrosinase activity 
# of melanin granules
size
distribution
rate of breakdown

Question 19

what is vitiligo due to?

Answer 19

due to a decrease or complete loss of melanocytes

autoimmunity or self-destruction of melanocytes

Question 20

what is albinism due to?

Answer 20

melanocytes are present by tyrosinase is defective so no melanin is formed

Question 21

Name the strata of the epidermis from superficial to deep.

Answer 21

1. stratum corneum
2. stratum lucidum
3. stratum granulosum
4. stratum spinosum
5. stratum basale

Question 22

which layer of epidermis is for “cell renewal”?

Answer 22

stratum basale

Question 23

cytoplasmic processes interdigitate btwn cells in which strata and appears as “railroad tracks”?

Answer 23

stratum spinosum

Question 24

what is the main function of stratum spinosum?

Answer 24

binding neighboring cells together via desmosomes

Question 25

stratum granulosum contains what two types of granules?

Answer 25

1. keratohyalin granules | 2. membrane-coating granuels (lamellar bodies)

Question 26

describe the strata of thin skin.

Answer 26

1. stratum corneum 2. stratum spinosum 3. stratum basale (absence of stratum lucidum and granulosum)

Question 27

where does teh dermis arise from?

Answer 27

mesoderm

Question 28

dermal papillae extend into overlying epidermis where they interdigitate w/ epidermal ridges projecting into the dermis

Answer 28

true

Question 29

free nerve endings transmit which sensation?

Answer 29

pain & temp

Question 30

pacinian corpuscles detect what sensation?

Answer 30

pressure, vibration

Question 31

Meissner's corpsucels detect what sensations?

Answer 31

mechanoreceptors, discriminatory, fine touch

Question 32

Krause end bulbs detects what sesnations?

Answer 32

function unclear

Question 33

what are eccrine sweat glands?

Answer 33

ordinary sweat glands found throughout the body

Question 34

where are apocrine sweat glands found?

Answer 34

axilla, areola of nipple, anal region

Question 35

what are eccrine sweat glands innervated by?

Answer 35

postganglionic sympathetic fibers

Question 36

what are apocrine sweat glands innervated by?

Answer 36

SNS

Question 37

which sweat gland follows holocrine secretion (whole cell is secreted)?

Answer 37

sebaceous gland

Question 38

which sweat glands follow merocrine secretion (only secretory producet is secreted)?

Answer 38

eccrine | apocrine

Question 39

where does nail growth occur?

Answer 39

nail matrix

Question 40

which disorder occurs as a result of auto-ab against desmoglein 1 and 3?

Answer 40

pemphigus vulgaris

Question 41

which disorder occurs as a result of auto-ab against desmoglein 1 only?

Answer 41

pemphigus foliaceus

Question 42

which disorder results as a result of genetic mutation encoding for structural proteins such as keratins, collagen type 7 or laminin?

Answer 42

epidermolysis bullosa

Question 43

which disease results due to genetic mutation encoding for type 7 collagen?

Answer 43

generalized recessive dystrophic epidermolysis bullosa