13_Devo Block 4.4 Dev Of Integumentary System

Front 1

1. Skin is derived from two layers:
2. What layer is does hair follicles, sweat and sebaceous glands and nails develop from?
3. What layer does the dermis arise?

Back 1

1. Superficial epi tissue from surface ectoderm; Deeper layer from mesoderm
2. Ectoderm
3. Dermis = mesoderm

Front 2

White greasy substance that covers the fetal skin:

Back 2

Vernix caseosa

Front 3

Proliferative primordial surface extodermal cells that form a layer of squamous epithelium:

Back 3

Periderm

Front 4

Epidermis, hair follicles, sweat and sebaceous glands, and nails develop from:

Back 4

Surface ectoderm

Front 5

Dermis forms from:

Back 5

Mesoderm

Front 6

The skin from the ventrolateral aspect of the body forms from:
The skin from back of the trunk is from:

Back 6

Somatic mesoderm
Dermatome

Front 7

At weeks 3-7, the epidermis is only:

Back 7

Surface ectoderm and a single layer of epithelial cells

Front 8

At week 7, the epidermis is:

Back 8

Surfac ectoderm is a bilayer; Outer layer is periderm and inner layer is germinal layer (mesenchyme)

Front 9

At week 11, the epiderms:

Back 9

Has an intermediate layer; Epidermal ridges produced by germinal layer extend into forming dermis

Front 10

At week 21, the periderm is replaced by:

Back 10

Stratum Corneum

Front 11

Where do most sebaceous glands develop?

Back 11

At buds from the sides of developing epithelial root sheaths of hair follicles.

Front 12

1. Dermis of the ventrolateral aspect of the body arises from:
2. Dermis from the back of the trunk:

Back 12

1. Somatic mesoderm
2. Dermatomes

Front 13

Describe how epidermis is formed and include weeks:

Back 13

1. Wk 3-7: Surface ectoderm is single layer of epithelial
2. Week 7: SE now a bilayer of Outer Periderm and Inner Germinal layer
3. Week 11: Intermediate layer present: Epi ridges produced by germinal layer exend into forming dermis
4. Week 21: Periderm replaced by stratum corneum

Front 14

What protects the fetal skin from damage by constant amniotic fluid exposure and made from sloughed periderm cells and sebum?

Back 14

Vernix Caseosa

Front 15

How does development of sebaceous gland compare with sweat glands?
1. Origin?
2. Structure - what it looks like
3. Length of duct
4. Secretion consistency
5. Time of function

Back 15

Review

Front 16

Why do sweat glands open onto surface of the skin but apocrine sweat open into hair follicles?

Back 16

1. Sweat glands develop as a downgrowth of epidermis into the dermis.
2. Their ducts open into the upper portion of hair follicles

Front 17

What is the origin of Hair vs Nails? When do nails reach digit tips?

Back 17

1. Hair is a down growth of the germinal layer of the epidermis into the dermis
2. Nails are thickened areas of epidermis at the tip of a digit that becomes located dorsally and surrounded by epidermal folds from which nail plate is formed. Reach digit tips at 32 (UL) and 26 (LL)

Front 18

When does hair begin to form? Nails?

Back 18

Early fetal period. Begins to form at week 10 for fingernail and 14 weeks for toenails.

Front 19

1. What is the hair that first appears at week 12 and in abundance by 7-20wks.
2. Describe it and its purpose

Back 19

1. Lanugo
2. Fine, soft, and lightly pigmented, helps hold the vernix caseosa onto the skin

Front 20

1. What is hair/skin pigment derived from?
2. How do these cells pigment the hair/skin
3. Where do these cells reside?

Back 20

1. Neural crest derived melanoblasts
2. During week 6-7 melanoblast appear in the dermis and migrate/differentiate into melanocytes that contain pigment granules that are transferred to cells in the base of the epidermis just before birth.
3. Cells reside between dermis an epidermis

Front 21

What are erector pili muscles derived from? Where are they found?

Back 21

Dermal mesenchyme next to forming hair follicles

Front 22

A baby with gray hair might have:
Resulting from:

Back 22

Albinism resulting from a lack of pigments

Front 23

What enzyme do albinos lack? What is the inheritance?

Back 23

Tyrosinase - autosomal recessive.

Front 24

What are the 4 stages of breast formation (include weeks)

Back 24

1. Mammary crests (week 4)
2. Mammary Buds (Week 6)
3. Secondary Buds (Week 12)
4. Mammary pit (late fetal period)

Front 25

Describe the mammary crest period of developement

Back 25

Thickened strips of ectoderm; extending into axilla to inguinal region

Front 26

Describe the mammary bud period of developement

Back 26

Solid down growths of epidermis of mammary crests into underlying mesenchyme

Front 27

Describe the secondary buds period of developement

Back 27

Formation of lactiferous ducts and branches. Ducts canalize through late gestation; 15-19 by term

Front 28

Describe the mammary pit period of development.

Back 28

It's the site of nipple formation

Front 29

1. What makes up the breast tissue of a newborn?
2. Postpuberal girl
3. Pregnant female

Back 29

1. Lactiferous ducts only
2. Ducts branch; alveoli form but rudimentary; fibrous stroma and fat accumulate
3. Alveoli develop

Front 30

What hormone affects breast development? What happens if pregnancy occurs?

Back 30

Estrogen and progesterone. If pregnancy then prolactin, corticoids, and growth hormone mediate development.

Front 31

What causes gynecomastia and what develops in these men?

Back 31

Decreased ratio of testosterone to estrogen. Rudimentary lactiferous ducts in the male breast develop.

Front 32

What are the five stages of tooth development (with weeks)

Back 32

1. Dental Lamina (week 6)
2. Bud stage (Week 7 deciduous; Week 10 permanent)
3. Cap stage (week 8)
4. Bell stage (Week 28)
5. Tooth eruption (Begins 6-8 months postnatal)

Front 33

Describe the dental lamina stage of development

Back 33

U-shaped thickening of oral ectoderm of upper and lower jaw

Front 34

Describe the bud stage stage of development

Back 34

Solid bud of ectoderm from dental lamina

Front 35

Describe the Cap stage of development

Back 35

Ectoderm cap called enamel organ having inner and outer enamel epithelium; mesenchym core called dental papilla; condesned mesnchyme around forming tooth is dental sac (follicle)

Front 36

Describe the bell stage of development

Back 36

Ammeloblasts from inner enamel epithelium; ondonontoblasts from dental papilla and cementoblasts from dental sac

Front 37

How many deciduous teeth vs permanent teeth

Back 37

20 vs 32

Front 38

Which teeth develop after birth?

Back 38

2nd and 3rd molars