Ch. 5 Epidermis

Question 1

superficial region; epithelial tissue

Answer 1

Epidermis

Question 2

20-30 layers of dead skin cells; essentially flat membranous sacs filled with keratin
-glycolipids in extracellular space

Answer 2

Stratum corneum

Question 3

only present in thick skin

Answer 3

Stratum lucidum

Question 4

typically 5 layers of flattened cells; organelles deteriorating; cytoplasm full of lamellar granules (release lipids) an keratohyaline granules

Answer 4

Stratum granulosum

Question 5

several layers of keratinocytes unified by desmosomes; cells contain thick bundles of intermediate filaments made of pre-keratin

Answer 5

Stratum spinosum

Question 6

one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers
-occasional melanocytes + dendritic cells

Answer 6

Stratum basale

Question 7

cells that produce keratin

Answer 7

Keratinocytes

Question 8

fibrous protein that makes structures hard and water-resistant

Answer 8

Keratin

Question 9

spider-shaped epithelial cells that synthesize melanin

Answer 9

Melanocytes

Question 10

dark pigment; gives color to skin and hair

Answer 10

Melanin

Question 11

arise from bone marrow and migrate to the epidermis; ingest foreign substances and activate the immune system

Answer 11

Dendritic cells

Question 12

associated with a disc-like sensory nerve ending; functions as a sensory receptor for touch

Answer 12

Tactile (Merkel) cell

Question 13

a process of controlled cellular suicide; eliminates cells that are unneeded, stressed, or aged
-sheds 50,000 cells every minute

Answer 13

Apoptosis