Skin

Question 1

layers of epidermis

Answer 1

stratum corneum, stratum granulosum, stratum spinosum, stratum basale

Question 2

layers of dermis

Answer 2

papillary dermis, reticular dermis

Question 3

stratum corneum (3 functions)

Answer 3

barrier, resist abrasion (squamous cells), waterproofing (lamellar bodies = caulking b/t cells)

Question 4

stratum granulosum

Answer 4

deep to stratum corneum; contains cytoplasmic keratohyaline granules (incl. filaggrin)

Question 5

filaggrin

Answer 5

a type of keratohyaline granule found in stratum granulosum; facilitates organization of keratin intermediate filaments - important for transition to anucleate cells of overlying stratum corneum

Question 6

stratum spinosum

Answer 6

cell types = keratinocyes and langerhans cells; keratinocytes attached to eachother w/ desmosomes;

Question 7

acantholysis

Answer 7

diseases where spinous cells lose desmosomal attachments, separate from eachother

Question 8

acanthosis

Answer 8

thickening of spinous layer

Question 9

stratum basale

Answer 9

cell types = keratinocytes and merkel cells; keratinocytes have a uniform size and shape with less cytoplasm than overlying cells; cap of melanin over this layer to protect DNA from UV light

Question 10

How long does maturation take from bottom to top of epidermis?

Answer 10

30 days

Question 11

3 important components of dermis

Answer 11

(1) fibroblasts: synth collagen and elastic fibers, (2) collagen, (3) elastic fibers

Question 12

papillary dermis

Answer 12

top layer of dermis; thin layer underneath epidermis, consists of delicate collagen fibers

Question 13

reticular dermis

Answer 13

deep to papillary dermis; contains thick collagen bundles in net-like pattern; superficial vascular plexus and deep vascular plexus

Question 14

vascular plexus in reticular dermin

Answer 14

(1) superficial: @ junction b/t papillary dermis and reticular dermis, (2) deep: b/t dermis and underlying subcutis

Question 15

subcutis

Answer 15

contains adipose; richly vascular; divided into lobules by fibrous “septa” (collagenous extensions from overlying dermis)

Question 16

where are the dermal papillae protrusions longest?

Answer 16

places with a lot of shear force (palms and soles of foot)

Question 17

rete ridges

Answer 17

on border of dermis and epidermis - for withstanding shear force (architectural feature of stratum basale)

Question 18

psoriasis

Answer 18

stratum corneum doesn’t come off fast enough -> thickened stratum corneum

Question 19

basal cell carcinoma

Answer 19

most common malignancy, occurring in stratum basale

Question 20

stratum basale basal cells

Answer 20

basal cell has desmosomes and hemidesmosomes to maintain the integrity of epidermis; gives rise to keritinocytes above it (replacing sloughed cells)

Question 21

melanocytes location and structure

Answer 21

in epidermis; have hemidesmosomes but not desmosomes to keratinocytes

Question 22

origin of melanocytes

Answer 22

neural crest cells

Question 23

function of melanocytes

Answer 23

make melanin, transfer it to basal keratinocytes

Question 24

melanosomes

Answer 24

brown bodies in melanocytes; skin color based on number of melanosomes, not melanocytes

Question 25

langerhans cell structure

Answer 25

in epidermis (stratum spinosum); cytoplasm has birbeck granules; no desmosomal attachments to keratinocytes

Question 26

origin of langerhans cells

Answer 26

bone marrow

Question 27

function of langerhans cells

Answer 27

intraepidermal antigen-presenting cell

Question 28

neural structures in skin

Answer 28

meissners corpuscle, merkel ending, pacinian corpuscle

Question 29

meissners corpuscle

Answer 29

messy nerve ending; senses light touch; located in acral skin

Question 30

merkel ending

Answer 30

in basal layer of epidermis; nerves come through basement membrane to touch the merkel cells, which provide a neural function

Question 31

pacinian corpuscle

Answer 31

circular lamella; present in skin that senses pressure and vibration

Question 32

skin appendages (3)

Answer 32

Hair, glands, nails

Question 33

Hair cycle

Answer 33

anagen (growing) –> catagen (involuting) –> telogen (resting)

Question 34

hair follicle

Answer 34

epithelial portion that supports growth of hair shaft

Question 35

where does hair color come from?

Answer 35

melanocytes donate melanin to hair shaft

Question 36

types of glands related to skin appendages

Answer 36

(1) sebaceous (2) eccrine (sweat) (3) apocrine (scent)

Question 37

function of subcutaneous tissue (hypodermis)

Answer 37

insulation, energy reserve, mechanical cushion

Question 38

sebaceous gland

Answer 38

for lubrication; found on hair-bearing skin, increased density on face, empties into hair follicle, lipid-producing sebocytes

Question 39

what type of secretion is involved for sebaceous glands?

Answer 39

holocrine

Question 40

eccrine glands

Answer 40

sweat glands for temp regulation; coiled gland; Na/K ATPase pumps in duct lining to resorb Na+

Question 41

acrosynringium

Answer 41

extension of eccrine gland to skin surface

Question 42

apocrine glands

Answer 42

for scent (i.e. pheromones); axillary and perineal; larger gland and acini than eccrine sweat gland; odorless secretion - converted to odor by bacteria on skin

Question 43

where are nails formed

Answer 43

at base of nail bed (matrix)