integumentary system

Question 1

keratinocytes

Answer 1

90% of epidermal cells and produce keratin

Question 2

merkel cells

Answer 2

associated with dermal nerve fiber, detect touch sensations

Question 3

langerhans cells

Answer 3

found in epidermis mainly in stratum spinosum, arise from red bone marrow, easily damaged by UV light

Question 4

melanocytes

Answer 4

8% of epidermal cells, produce melanin

Question 5

5 epidermal layers

Answer 5

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum.

Question 6

stratum basale

Answer 6

deepest layer

simple cuboidal or columnar, attached to each other by desmosomes and to basal lamina by hemidesmosomes.

Question 7

stratum spinosum

Answer 7

above stratum basale
8-10 layers of keratinocytes
bound together by desmosomes and tight junctions, has Langerhans cells

Question 8

stratum granulosum

Answer 8

above spinosum, cells connected by desmosomes and tight junctions, 3-5 layers of flattened keratinocytes undergoing apoptosis

Question 9

stratum lucidum

Answer 9

3-5 layers of flattened clear dead keratinocytes, present in thick skin
keratinocytes have a thick plasma membrane and are packed with a clear protein called eleidin

Question 10

stratum corneum

Answer 10

15-30 layers of flat dead keratinocytes, connected by desmosomes, protect deep layers from injury and microbial invasion

Question 11

how long does it take to make and shed keratinocytes

Answer 11

30-40 days

Question 12

where is the dermis and whats it made of

Answer 12

deeper to the epidermis connective tissue

Question 13

papillar layer

Answer 13

superficial 1/5 of total layer, made of areolar connective tissue and fine elastic fibers