Biology Of The Skin: Structure And Function

Front 1

Name the pigment producing cells of the skin.

Back 1

Melanocytes are the pigment producing cells of the skin.

Front 2

Where do melanocytes originate?

Back 2

Melanocytes originate in the neural crest.

Front 3

When do melanocytes migrate?

Back 3

Melanocytes migrate in the 8th week of fetal development.

Front 4

To what sites do melanocytes migrate?

Back 4

Melanocytes migrate to the basal layer of the epidermis, the hair matrices, the inner ear, the uveal tract, and the leptomeninges.

Front 5

What receptor-ligand interactions are required for melanocyte survival and migration in the CNS

Back 5

In the CNS endothelin B receptors interact with endothelin 3.

Front 6

What receptor-ligand interactions are required for melanocyte survival in the mesenchyme and final destination sites?

Back 6

The KIT receptor on melanoblasts and melanocytes interact with steel factor.

Front 7

Mutations in EDN3 or EDNRB lead to lack of appropriate migration of melanocytes causing what disease?

Back 7

Mutations in EDN3 or EDNRB lead to Waardenburg type 4.

Front 8

Mutation in the KIT gene leads to what disease?

Back 8

Mutation in KIT gene results in lack of migration of melanocytes leading to piebaldism.

Front 9

At birth where are dermal melanocytes found?

Back 9

Dermal melanocytes are found in the head, neck, distal extremities, and the presacral area.

Front 10

What diseases result from dermal melanocytosis?

Back 10

Dermal melanocytosis results in nevus of Ota, nevus of Ito, mongolian spots, and blue nevi.

Front 11

What connects melanocytes to keratinocytes?

Back 11

Cadherins connect melanocytes to keratinocytes.

Front 12

Name two populations of melanocytes in the skin.

Back 12

1. Interfollicular melanocytes

2. Hair matrix melanocytes

Front 13

What determines skin color?

Back 13

The quantity and quality of melanin production determines skin color.

Front 14

What stimulates melanocyte activity?

Back 14

UV light, estrogens, progesterone, and certain medications stimulate melanocyte activity.

Front 15

What unique secretory organelles are found in melanocytes?

Back 15

Melanosomes are unique secretory organelles found in melanocytes.

Front 16

What secretory organelles resemble melanosomes and share many of the same biosynthetic pathways.

Back 16

Lysosomes resemble melanosomes and share many of the same biosynthetic pathways.

Front 17

Name the enzyme that catalyses the conversion of tyrosine-->dopa-->dopaquinone.

Back 17

Tyrosine catalyses the conversion of tyrosine-->dopa-->dopaquinone.

Front 18

What element is bound to the enzyme tyrosinase?

Back 18

Copper is bound to tyrosinase.

Front 19

Defects in tyrosinase result in what disease?

Back 19

Defects in tyrosinase result in OCA-1.

Front 20

Name a chemical used in cosmetic products that competitively inhibits tyrosinase.

Back 20

Hydroquinone competitively inhibits tyrosinase.

Front 21

Name an amino acid that competitively inhibits tyrosinase.

Back 21

L-phenylalanine competitively inhibits tyrosinase.

Front 22

What does the P protein do?

Back 22

The P protein is involved in processing and traffiking tyrosinase.

Front 23

What disease results from a mutation in the P protein?

Back 23

Mutations in the P protein result in OCA 2.

Front 24

Name the two major types of melanin.

Back 24

1. Eumelanin

2. Pheomelanin

Front 25

The binding of MSH to the MC1-R receptor on the melanocyte results in which type of melanin?

Back 25

The binding ot MSH to the MC1-R receptor results in the synthesis of eumelanin.

Front 26

The binding of the agouti protein to the MC1-R receptor on the melanocyte results in which type of melanin?

Back 26

The binding of the agouti protein to the MC1-R receptor results in the synthesis of pheomelanin.

Front 27

Basic pH favors which type of melanin formation?

Back 27

Basic pH favors the formation of eumelanin.

Front 28

How do eumelanosomes differ in appearance from pheomelanosomes?

Back 28

Eumelanosomes are oval with various stages of pigment production. Pheomelanosomes are round and contain vesicular bodies.

Front 29

What is the protein product of the POMC gene?

Back 29

MSH is the protein product of the POMC gene.

Front 30

Mutations in the POMC gene result in what phenotype?

Back 30

Mutation in the POMC gene results in obesity, adrenal insufficiency, and red hair.

Front 31

Mutation in the MC1-R gene results in what phenotype?

Back 31

Mutation in the MC1-R gene results in red hair.

Front 32

Mutation in the MC4-R gene results in what phenotype?

Back 32

Mutation in the MC4-R gene results in morbid obesity.

Front 33

What causes the red hair phenotype?

Back 33

Most red hair is due to four loss of function mutations in the MC1-R gene.