Non-keratinocyte epidermal cells, and appendages

Question 1

what are the non-keratinocyte epidermal layer cells

Answer 1

melanocytes(basal + suprabasal), Langerhans cells(suprabasal), Merkel cells(basal)

Question 2

briefly describe what melanocytes are

Answer 2

pigment producing dendritic cells

Question 3

describe the role of melanocytes

Answer 3

convert tyrosine to melanin pigment, melanin absorbs light, forms protective cap over nucleus

Question 4

describe where the organelles in melanocytes, full melanosomes(‘melanin granules’) are transferred to and via what

Answer 4

transferred to adjacent keratinocytes, via dendrites

Question 5

where are Langerhans cells found

Answer 5

prickle cell layer of epidermis, dermis and lymph nodes

Question 6

describe Langerhans cells involvement in the immune system

Answer 6

antigen presenting cells, pick up antigen in skin and circulate to lymph nodes via lymphatic system

Question 7

what is the origin of Langerhans cells

Answer 7

mesenchymal origin - bone marrow

Question 8

describe where Merkel cells found

Answer 8

in the basal epidermis between keratinocytes and nerve fibres

Question 9

what is the function of Merkel cells

Answer 9

mechanoreceptors

Question 10

what is another name for a hair follicle

Answer 10

Pilosebaceous unit

Question 11

describe what hair pigmentation is due to

Answer 11

via melanocytes above the dermal papilla

Question 12

what is the pilosebaceous unit made up of

Answer 12

the epidermal component plus the dermal papilla

Question 13

what are the different growth cycles of hair

Answer 13

anagen(growing), catagen(involuting), telogen(resting/shedding phase)

Question 14

describe how long each of the hair growth phases takes

Answer 14

anagen = 3-7 years(90% of hairs)
catagen = 3-4 weeks(10% hairs)
telogen = each day 50-100 hairs(<1%)

Question 15

what word is used to describe the pattern of telogen phase of hair growth in humans

Answer 15

asynchronous

Question 16

what are both nails and hair shafts made up of

Answer 16

specialised keratins

Question 17

describe the growth rate of nails

Answer 17

0.1mm a day, fingers > toes, summer > winter