BIO 168 - Layers of Dermis and Epidermis

Question 1

Basale

Answer 1

Deepest layer of epidermis. Composed of a single row of cuboidal or columnar keratinocytes. Stem cells undergo cell division to produce new keratinocytes.

Question 2

Spinosum

Answer 2

2nd deepest layer of epidermis. Eight to ten rows of many sided keratinocytes with bundles of keratin intermediate filaments. Contains armlike processes of melanocytes and langerhans cells.

Question 3

Granulosum

Answer 3

3rd deepest layer of epidermis. Three to five rows of flattened keratinocytes, in which organelles are beginning to degenerate.

Question 4

Lucidum

Answer 4

Present only in skin of fingertips, palms, and soles; consists of 4 to 6 rows of clear, flat, dead keratinocytes with large amounts of keratin.

Would be between granulosum and corneum

Question 5

Corneum

Answer 5

25-30 rows of dead, flat keratinocytes that contain mostly keratin.

Question 6

Papillary

Answer 6

Superficial portion of dermis (about 20%) consists of dense irregular connective tissue with thin collagen and fine elastic fibers; contains dermal ridges that house capillaries, Meissner corpuscles, and free nerve endings.

Question 7

Reticular

Answer 7

Deeper portion of dermis (about 80%) consists of dense irregular connective tissue with bundles of thick collagen and some coarse elastic fibers. Spaces between fibers contain some adipose cells, hair follicles, nerves, sebaceous glands, and sudoriferous glands.