Lecture 13

Question 1

describe the periderm

Answer 1

single layer of ectodermal cells

formed by end of first month

Question 2

describe the three layered epidermis

Answer 2

formed by end of third month
basal layer
intermediate layer
superficial peridermal layer

Question 3

describe melanoblasts

Answer 3

from neural crest
migrate into dermis and then into epidermis
strain with HMB-45
produce pigment by mid pregnancy

Question 4

describe langerhans’ cells

Answer 4

derived from bone marrow

antigen presenting cells

Question 5

describe Merkel cells

Answer 5

from neural crest

slow adapting mechanoreceptors

Question 6

The dorsal surface of the body is mesenchyme to _____

Answer 6

dermatome

Question 7

the ventral and lateral surfaces of the body are mesenchyme from _______

Answer 7

lateral plate mesoderm

Question 8

cranial and anterior neck and mesenchyme mostly from ______ crest

Answer 8

cranial neural

Question 9

Induction where one germ layer instructs another on how to differentiate is referred as ______

Answer 9

instructive induction

Question 10

What are the epidermal derivatives?

Answer 10

hair
nails
mammary glands

Question 11

Wnt-11 and ____ from mesoderm cause ectoderm to express _____

Answer 11

FGF; noggin

Question 12

Eda from mesoderm causes ectoderm to express ____

Answer 12

edar

Question 13

Edar and _____ in ectoderm block ____

Answer 13

noggin; BMP

Question 14

other _____ act through B-catenins

Answer 14

Wnts

Question 15

in interfollicular zones what happens?

Answer 15

Dickkopf blocks Wnt

BMP inhibits follicle development

Question 16

in the induction of the dermal papilla, the expression of _____ via the signaling pathway involving Eda receptor stimulations formation of dermal papilla below _____ placode

Answer 16

Shh; epidermal

Question 17

Final differentiation of hair primordia involves ___ genes

Answer 17

Hox