Exam 2

Question 1

order of epidermis layers

Answer 1

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (in thick skin), stratum corneum

Question 2

order of dermis layers

Answer 2

papillary layer, reticular layer

Question 3

keratinocyte

Answer 3

major cell type of the epidermis

located in stratum basal and lower part of stratum spinous

Question 4

keratinization

Answer 4

formation of tonofibrils, formation of keratohyalin granules, association of keratohyalin granule proteins with tonofibrils (stratum lucidum)

Question 5

tonofilament

Answer 5

intermediate filament composed of keratin formed in the stratum basale

Question 6

keratohyalin granules

Answer 6

basophilic aggregations of free polysomes that produce histidine-rich and cysteine-rich proteins, produced in the upper stratum spinous and stratum granulosum

Question 7

soft keratin

Answer 7

combination of tonofibrils and the proteins of the keratohyalin granules

Question 8

hard keratin

Answer 8

trichohyalin granules produced and monofilaments become more extensively cross-linked to amorphous keratin via disulfide bonds

Question 9

membrane-coating granules (MCGs) aka lamellar bodies

Answer 9

Contribute a lipid bilayer to the epidermal water barrier

membrane-bound organelles first produced in the stratum spinosum

Question 10

melanocyte

Answer 10

between cells of the stratum basale, derived from the neural crest

Question 11

tyrosinase

Answer 11

enzyme that converts tyrosine into dopa and then dopaquinone (precursors of melanin)

Question 12

Langerhans cell

Answer 12

pale-staining cell with elongated cell process of bone marrow origin function as antigen-presenting cell, can act as a viral reservoir that harbors AIDS, contain the Birbeck granule

Question 13

Merkel cell

Answer 13

found on basement membrane, function as touch receptors in thick skin (finger tips, lips), slow to adapt

Question 14

thick skin

Answer 14

has all five layers of the epidermis
found only on the palms of hands and the soles of the feet
is glabrous (hairless)

Question 15

thin skin

Answer 15

has no stratum lucidum
is located on most parts of the body
is vellus (hairy)

Question 16

papillary layer

Answer 16

superficial layer of the dermis, loose connective tissue, upper surface has dermal papillae, more connective tissue cells than reticular layer

Question 17

reticular layer

Answer 17

deeper layer of the dermis, dense irregular connective tissue

Question 18

Meissner’s corpuscles

Answer 18

encapsulated receptors formed by modified Schwann cells giving a layered or zigzag appearance, detect light touch

Question 19

Pacinian corpuscles

Answer 19

encapsulated receptors that respond to deep touch or vibration, located in the deep dermis or hypodermis

Question 20

hypodermis

Answer 20

not actually a part of skin, consists of loose connective tissue and adipose tissue that binds skin to underlying organs

Question 21

glassy membrane

Answer 21

thick basement membrane that surrounds the hair follicle

Question 22

external root sheath

Answer 22

composed of epithelial cells and is continuous with the epidermis

Question 23

hair bulb

Answer 23

base of the follicle, matrix epithelial cells, also contains melanocytes

Question 24

internal root sheath

Answer 24

lies between external root sheath and hair shaft, composed of keratinized epithelial cells

Question 25

hair shaft

Answer 25

composed of hard keratin and three parts: medulla, cortex, and cuticle

Question 26

Arrector pili muscle

Answer 26

bundle of smooth muscle attaches to skin and CT sheath outside the glassy membrane, contraction raises the hair shaft to a more vertical position and causes goose bumps

Question 27

vellus hair

Answer 27

thin, short, poorly pigmented hair

Question 28

terminal hair

Answer 28

thicker, longer and more heavily pigmented hair

Question 29

anagen

Answer 29

period of active growth (when matrix cells divide)

Question 30

catagen

Answer 30

period of involution when the lower part of the follicle below the arrestor pili muscle atrophies

Question 31

telogen

Answer 31

resting period between the end of follicular atrophy and the shedding of the hair

Question 32

sebaceous glands

Answer 32

acinar exocrine glands with a holocrine mode of secretion for sebum

Question 33

eccrine sweat glands

Answer 33

simple coiled tubular exocrine glands with ducts that open directly onto skin surface and distributed over entire body except for lips and parts of external genitalia

Question 34

secretory portion of eccrine sweat glands

Answer 34

psuedostratified cuboidal epithelia, lighter staining, located deep in the hypodermis, surrounded by myoepithelial cells

Question 35

duct portion of eccrine sweat glands

Answer 35

lined by stratified cuboidal epithelium (2 layers), reabsorbs NaCl from the secretion to prevent excessive salt loss, no myoepithelial cells

Question 36

apocrine sweat glands

Answer 36

coiled tubular exocrine glands found on axilla, areola, nipple, perianal region and external genitalia

Question 37

secretory portion of apocrine sweat glands

Answer 37

wide lumen lined by simple epithelium surrounded by myoepithelial cell

Question 38

duct portion of apocrine sweat glands

Answer 38

narrow duct lined by 2-3 layers of cuboidal cells

Question 39

nail plate

Answer 39

hard portion of the nail

Question 40

nail root

Answer 40

skin that covers proximal portion of the nail plate

Question 41

nail matrix

Answer 41

proximal end of nail root with stem cells that nail plate grows

Question 42

lunula

Answer 42

crescent-shape at the proximal end of the visible portion of the nail, partially keratinized cells

Question 43

nail bed

Answer 43

made up of stratum basale and stratum spinous which are continuous with those layers surrounding the skin

Question 44

eponychium

Answer 44

cuticle made of hard keratin

Question 45

hyponychium

Answer 45

thickened epithelial layer that secures the free end of the nail plate to the fingertip

Question 46

cyanosis

Answer 46

pale blue color of nail plate due to poor oxygenation in the circulating blood

Question 47

split nails

Answer 47

indicative of nutritional deficiencies

Question 48

clubbing

Answer 48

thickening of the nail base and wrapping of nail plate around the sides of the finger

Question 49

spoon-shaped (concave) nails

Answer 49

indicative of iron deficiency anemia

Question 50

psoriasis

Answer 50

increased rate of cellular proliferation resulting in accumulation of cells of the stratum corneum, producing pink-red areas with flakes or plaques

Question 51

warts

Answer 51

benign epidermal growths caused by papilloma viral infection of keratinocytes

Question 52

basal cell carcinoma

Answer 52

least deadly form involving cells of stratum basale usually due to excessive UV radiation, malignant cells rarely spread beyond skin (dermis or epidermis)

Question 53

squamous cell carcinoma

Answer 53

can be deadly if spreads, involves cells of stratum spinosum, probably caused by radiation or chemical agents

Question 54

malignant melanoma

Answer 54

involves melanocytes, rapidly dividing cells, invasive