Non-Keratinocyte Epidermal Cells and Appendages

Question 1

what is perspiration insesilibis

Answer 1

unconscious perspiration to maintain core temp

Question 2

function and location of melanocytes

Answer 2

pigment-producing dendritic cells

basal and suprabasal

Question 3

function and location of Langerhans cells

Answer 3

detect microbes

prickle cell layer, epidermis, dermis and lymph nodes

Question 4

function and location of Merkle Cells

Answer 4

detect pressure - nerve cell

basal

Question 5

describe the path of melanocytes during development

Answer 5

in the first 3 months, they migrate from the neural crest to the epidermis

Question 6

what are melanosomes and what is their function

Answer 6

organelles in melanocytes

convert tyrosine to melanin pigment, melanin is tightly packed in melanosomes

Question 7

eumelanin colour

phaeomelanin colour

Answer 7

brown/black

red/yellow

Question 8

describe the process of a mole forming

Answer 8

melanin absorbs light and full melanosome transfer the pigment to adjacent melanocytes via dendrites
this forms a protective cap over the nucleus to protect DNA, light cannot prenetrate

Question 9

what hormone stimulates formation of moles

Answer 9

alpha-melanocyte stimulating hormone

Question 10

what is melanin derived from

Answer 10

tyrosine product (aa)

Question 11

where are Langerhans cells derived from

Answer 11

mesenchymal - bone marrow

Question 12

what type of receptors are Merkel cells

Answer 12

mechanoreceptors

Question 13

where are merkel cells

Answer 13

between keratinocytes and nerve fibres

Question 14

what is a pilosebaceous unit

Answer 14

hair and grease producing unit

Question 15

how does hair pigmentation occur

Answer 15

melanocytes above dermal papilla

Question 16

describe the embryology of hair

Answer 16

hair but is formed from a fibroblast in the mesoderm and is produced in the epidermis
hair papilla and shaft form
blood vessels supply the papilla
epithelial shaft, dorsal root and sebaceous gland forms
smooth muscle fibres attach

Question 17

what are the 3 phases of growth and decsribe them

Answer 17

anagen - growing
catagen - involuting
telogen - resting

Question 18

describe anagen

Answer 18

3-7 years
most hairs
growth

Question 19

describe catagen

Answer 19

3-4 weeks

papilla and hair dissociates

Question 20

describe telogen

Answer 20

asynchronus shedding of hair

50-100 a day

Question 21

what is lunula of the nail made of

Answer 21

keratin

Question 22

how do nails grow

Answer 22

stem cells thicken and form the nail matrix under the skin

the stem cells then grow out