INTEGUMENTARY

Question 1

superficial epithelial tissue that is derived from surface embryonic ectoderm.

Answer 1

Epidermis

Question 2

deep layer composed of dense, irregularly arranged connective tissue that is derived from mesenchyme.

Answer 2

Dermis

Question 3

at 4 to 5 weeks consists of a single layer of surface ectoderm overlying the mesoderm

Answer 3

Embryonic skin

Question 4

(keratin formation or development of a horny layer

Answer 4

Keratinization

Question 5

(shedding of cuticle, the outer, thin layer)

Answer 5

Desquamation

Question 6

During the fetal period, it protects the developing skin from constant exposure to amniotic fluid with its high content of urine, bile salts, and sloughed cells. It also facilitates birth of the fetus.

Answer 6

Vernix caseosa

Question 7

The basal layer of the epidermis becomes the _________, which produces
new cells that are displaced into the more superficial layers.

Answer 7

Stratum germinativum

Question 8

By 11 WEEKS, cells from the stratum germinativum have formed

Answer 8

Intermediate layer

Question 9

Replacement of peridermal cells continues until WHAT WEEK?

Answer 9

21 weeks

Question 10

periderm disappears and the _______ forms from the stratum lucidum

Answer 10

Stratum corneum

Question 11

begin to appear in embryos at 10 weeks and are permanently established by 19 weeks

Answer 11

Epidermal ridges

Question 12

True or false. Those of the hand appear approximately 1 week earlier than ridges in the feet.

Answer 12

True

Question 13

produce grooves on the surface
of the palms and soles, including the digits (fingers and toes)

Answer 13

Epidermal ridges

Question 14

Late in the embryonic period, neural crest cells migrate
into the mesenchyme of the developing dermis and differentiate into _____

Answer 14

melanoblasts (cells derived from the neural crest)

Question 15

These cells migrate to the _________ and differentiate into _____

Answer 15

Dermo-Epidermal junction & Melanocytes (pigmen-producing cells)

Question 16

Differentiation of melanoblasts into melanocytes involves the formation of

Answer 16

pigment granules (grain-like particles).

Question 17

covers the palms of the hands and soles of the feet; it lacks hair follicles, arrector muscles of hairs, and sebaceous glands, but it has sweat glands.

Answer 17

Thick skin

Question 18

covers most of the rest of the body; it contains hair follicles, arrector muscles of hairs, sebaceous glands, and sweat glands

Answer 18

Thin skin

Question 19

first hairs to appear are called ______? They are fine, soft, and lightly pigmented. Lanugo begins to appear toward the end of the 12th week and is plentiful by 17 to 20 weeks

Answer 19

Lanugo