Integument

Question 0

What is dermis?

Answer 0

Dense irregular CT derived from mesenchyme

Question 1

What is epidermis?

Answer 1

Stratified squamous orthokeritinized epithelial tissue derived from surface ectoderm

Question 2

What does surface ectoderm proliferate to become?

Answer 2

keratinoblasts

Question 3

keratinoblasts form what layers?

Answer 3

basal (germinal) layer and squamous periderm

Question 4

What is vernix caseosa?

Answer 4

white greasy substance formed by exfoliating peridermal cells

Question 5

What is the function of vernix caseosa?

Answer 5

• protective covering for fetal skin

- greasy covering facilitates birth of fetus

Question 6

In week 11 the keratinoblasts continue to proliferate to form what?

Answer 6

intermediate layer

Question 7

Fingerprints are due to what in the dermis?

Answer 7

rete pegs and dermal papillae

Question 8

What is the periderm replace by?

Answer 8

stratum corneum

Question 9

Is all the epidermal strata present at birth?

Answer 9

yes

Question 10

How do melanocytes come to be?

Answer 10

melanoblasts cross dermo-epidermal junction

Question 11

What begins prior to birth in regards to melaocytes?

Answer 11

melanin production

Question 12

What is Ichthyosis?

Answer 12

skin disorder resulting from excessive keratinization

Question 13

What is curtailed as a results of excessive keratinization in Ichthyosis?

Answer 13

hair growth and development of sweat glands

Question 14

What is generalized albinism?

Answer 14

lack of pigmentation in skin, hair, and retina due to lack of enzyme tyrosinase in melanocytes

Question 15

What is piebaldism?

Answer 15

localized albinism

Question 16

WHat is the dermis derived from?

Answer 16

mesenchyme of the somatic layer of lateral plate mesoderm

Question 17

What produces collagen and elastic fibers?

Answer 17

fibroblasts

Question 18

What process of sensory neurons grow into developing dermis?

Answer 18

peripheral processes

Question 19

What is the result of vasculogenesis?

Answer 19

results in simple endothelial lined tubes forming in mesenchyme

Question 20

What is angiogenesis?

Answer 20

the process of new vessels protruding from pre-existing vessels

Question 21

What is a hemangioma?

Answer 21

a vascular anomaly resulting from persistent surplus of primitive blood vessels in dermis

Question 22

Where do nails form?

Answer 22

at tips of digits ~10 weeks

Question 23

Which develops before the other, fingernails or toenails?

Answer 23

fingernails

Question 24

What is the difference between nail fields and hyponychium?

Answer 24

hyponychium is the nail field after nail plate has formed

Question 25

What is an eponychium?

Answer 25

the cuticle - narrow band of epidermis covering the proximal base of the nail plate

Question 26

What are nail folds?

Answer 26

form as epidermal cells proliferate laterally and proximally to nail fields

Question 27

Proliferation and keratinization in proximal fold leads to formation of what?

Answer 27

nail plate

Question 28

What is anonychia?

Answer 28

absence of nails at birth

Question 29

Where are hairs first recognizeable?

Answer 29

eyebrows, upper lip and chin

Question 30

What does the hair follicles begin as?

Answer 30

proliferation of stratum basal into underlying dermis

Question 31

What are the peripheral epithelial cells of the invaginating hair follicle called?

Answer 31

epithelial root sheath

Question 32

What is the dermal root sheath?

Answer 32

dermal mesenchymal cells surrounding the epithelial root sheath

Question 33

What is a hair bulb?

Answer 33

club shaped deep end of hair follicle which serves as the germinal center

Question 34

What forms as cells in the germinal center proliferate and become keratinized?

Answer 34

hair shaft

Question 35

Ho do we have different hair colour?

Answer 35

melanoblasts migrate into bulb and differentiate into melanocytes

Question 36

What are hair papilla?

Answer 36

small dermal invagination into hair bulb providing vascular support

Question 37

What develop from mesenchyme in dermis and span from dermal root sheath to papillary dermis?

Answer 37

arrector pili muscles

Question 38

What are lanugo?

Answer 38

very fine, soft and lightly pigmented first hairs

Question 39

What is the lanugo replaced by?

Answer 39

coarser hairs

Question 40

What is alopecia?

Answer 40

absence or loss of scalp hairs

Question 41

What defines the congenital condition of alopecia? the aquired condition?

Answer 41

``` congenital = failure of hair follicles to form acquired = follicles producing poor quality or no hairs ```

Question 42

What is hypertrichosis?

Answer 42

excessive hairiness which may be localized or diffuse

Question 43

How do sebaceous glands develop?

Answer 43

as acinar buds from the epithelial root sheaths into the surrounding dermal CT

Question 44

What are the difference between periphery buds and central buds?

Answer 44

``` periphery = mitotically active central = broken down and die to produce sebum ```

Question 45

Where are eccrine sweat glands located?

Answer 45

located in skin throughout the body

Question 46

Where is the secretory component of eccrine sweat glands located?

Answer 46

located deep within dermis and coils in on itself

Question 47

What do cells differentiate into in the secretory component of eccrine sweat glands?

Answer 47

secretory cells and myoepithelial cells

Question 48

What are the importance of eccrine sweat glands?

Answer 48

postnatal evaporation results in cooling effect

Question 49

What is the sweat duct or excretory component of eccrine sweat glands?

Answer 49

canalized segment of tubular bud remaining connected to surface

Question 50

Where are apocrine sweat glands located?

Answer 50

axilla, areola of nipples, pubic regions and perianal regions

Question 51

What is the secretory activity of apocrine sweat glands?

Answer 51

begins during puberty | - postnatal bacterial action contributes to pheromone activity

Question 52

What are mammary crests?

Answer 52

thickened strips of ectoderm extending from axillary to inguinal regions

Question 53

What are mammary buds?

Answer 53

pectoral epidermal invaginations of mammary crest into underlying mesenchyme

Question 54

The primary mammary buds give rise to secondary mammary buds which give rise to what?

Answer 54

lactiferous ducts

Question 55

The surrounding mesenchyme forms what in the breast region?

Answer 55

fibrous CT and fat

Question 56

What are the differences between male and female mammary glands?

Answer 56

- females develop secretory acini and accumulate fat during puberty - male breats remain rudimentary throughout life (still contain lactiferous ducts but no secretory acini)

Question 57

What is gynecomastia?

Answer 57

further development of male mammary tissue (lactiferous ducts and adipose)

Question 58

What is athelia?

Answer 58

rare absence of nipple development or breast development

Question 59

What is athelia (amastia) caused by?

Answer 59

absence of mammary crest formation or mammary bud development

Question 60

What is polythelia (polymastia)?

Answer 60

an extra nipple or breast | - supranumerary nipples in men are often mistaken for moles