Fitz9. Ch7: Biology of hair

Question 1

Responsible for nonrandom and symmetrical distribution of hair follicles

Answer 1

Patterning genes or homeobox genes

Question 2

Dorsal ventral patterning

Answer 2

Engrailed

Question 3

Hair length

Answer 3

FGF5

Question 4

Hair curl

Answer 4

Keratin 71

Question 5

Hair distribution

Answer 5

R spondin 2

Question 6

Hair thickness

Answer 6

EDAR or ectodysplasin receptor

Question 7

Inner root sheath differentiation

Answer 7

GATA3

Question 8

Earliest molecular pathway that positively regulate hair follicle initiation and is the downstream mediator of WNT signaling

Answer 8

WNT/B catering pathway

Question 9

Stimulate early follicle development and is mutated in X-linked anhidrotic ectodermal dysplasia

Answer 9

ectodysplasin or EDA

Question 10

Inhibit follicle formation

Answer 10

BMP or bone morphogenic protein

Question 11

Major role in epithelial mesenchymal signaling

Answer 11

Sonic hedgehog signaling or SHH

Question 12

A receptor of SHH that is deficient in basal cell nevus syndrome

Answer 12

Patched1

Question 13

Duration, size, and length of lanugo

Answer 13

1-3 months
40um
1-2 cm

Question 14

The shortest hair type is

Answer 14

Miniaturized hair follicles with < 1 week

Terminal to vellus I’m androgenetic slope is

Question 15

Vellus hair

Duration
Size
Hair bulb location

Answer 15

Vellus is
1-2 weeks,
<30um (or half of terminal hairs, <2 cm),
Hair bulb is Located in reticular dermis

Question 16

Terminal hairs

Answer 16

> 1 year
60 um, 10 to 100 cm
Hair bulb in subcutaneous fat (deeper)

Question 17

Isthmus lacks what layer?

Answer 17

Granular layer

Note: outer root sheath has a granular layer but lacks this layer in the isthmus

Question 18

Four parts of the inner root sheath from outer to inner

Answer 18

Companion layer, henle, Huxley, inner root sheath cuticle layer

(Alphabetical)

Question 19

This layer in inner root sheath is only one cell layer thick and is the first to develop keratohyaline granules and the first to keratinize

Answer 19

Henle layer

Question 20

(1)This inner root sheath layer has 2-4 cell layers thick and keratinizes above the adjacent layer at a region known as______(2)

Answer 20

1. Huxley

2. Adamson fringe

Question 21

Cells within the Huxley layer protrude through Henle and attach to the companion layer

Answer 21

Fluegelzellen or wing cells

Question 22

Transcripts factor critical in inner root sheath differentiation

Answer 22

GATA3

Question 23

Part of the hair comprised of fibroblasts, collagen bundles, mucopolysaccharide rich stromatolites, nerve fibers and a single capillary hair

Answer 23

Dermal papilla

Question 24

Sense pressure

Answer 24

Merkel cell

Question 25

Detect tension

Answer 25

Ruffini

Question 26

Consists of an inner basement membrane (hyaline membrane) and an outer connective tissue sheath

Answer 26

Perifollicular sheath

Question 27

There are 7 stages of Anagen what are they?

Answer 27

1. Growth of dermal papilla
2. Bulb matrix cells ENVELOPE the dermal papilla
3. Bulb matrix cell DIFFERENTATION
4. Matrix MELANOCYTES activate
5. Hair shaft emerges and dislodges telegenic hair
6. New hair shaft emerges
7. Stable growth

Question 28

Melanocyte stem cells are detected in hair _____

Answer 28

Hair bulge

Question 29

Controls melanocyte stem cells

Answer 29

TGF beta

Question 30

File in survival of melanocyte stem cells

Answer 30

Notch signaling

Question 31

Bcl2

Answer 31

Role in maintenance of stem cells

Question 32

Hair color

Answer 32

Melanocortin 1

Question 33

Hair darkening

Answer 33

Noggin

Question 34

Regulator of pigment production

Answer 34

Protein kinase C