lect 26 & 27 (T3): integument Flashcards Preview

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Flashcards in lect 26 & 27 (T3): integument Deck (48):
1

what does the dermis of the skin correspond to

lamina propria of a mucous membrane

2

what are characteristics of the primary dermal ridge

related to finger prints
found everywhere except forehead, external ear, perineum, and scrotum
formed during 3rd to 4th months of fetal life
subdivided into 2 secondary dermal ridges by inter papillary peg

3

what is the inter papillary peg

downward growth of epidermis along crest

4

what are characteristics of the secondary dermal ridge

occur in double rows, branched
thin, collagenous, reticular and elastic fibers

5

what is the dermal papillae

upward projections from each secondary dermal ridge

6

what are characteristics of thick skin

occurs only on palms and soles and is hairless
displays all 5 epidermal layers

7

what are characteristics of thin skin

occurs over rest of body
thinnest in eyelids
thickest on back
thicker on extensor surfaces than flexor
epidermal layers less distinct and lacking stratum lucidum

8

what are the layers of the epidermis

stratum basale (deepest)
stratum spinosum
stratum granulosum (represented by only a few cells in thin skin)
stratum lucidum (absent in thin skin)
stratum corenum (most superficial)

9

what types of cells are in the stratum basale

single layer cells held together by desmosomes (hemidesmosomes hold layer to basal lamina)

10

what does mitotic activity in the stratum basal produce

stem cells differentiating keratinocytes

11

what type of cells are in the stratum spinosum

polyhedral shaped cells (prickle cells)

12

what keratins are in stratum spinosum

keratins 1 and 10 (high molecule weight)

13

what keratins are in stratum basale

keratins 5 and 14 (low molecular weight0

14

what do the lamellar bodies in stratum spinosum contain

lipid, carbs, and hydrolytic enzymes

15

what do tonofibrils do

form intercellular bridges

16

what are characteristics of stratum granulosum

multilayerd
keratins 2e and 9
flattened nucleated keratinocytes
keratohylain aggregates
membrane-coating granules (lamellar bodies)
tonofilaments

17

keratokyalin aggregates do what

filagrin induces cross-linkage of keratin filaments by disulfide bonds
no limiting membrane

18

what are characteristic lucidum

flat keratinocytes lacking nuclei and organelles
only found in thick skin
contains eleiden

19

what are characteristics of stratum corneum

multilayered
thicker in thick skin
enucleated, flattened, dead keratinocytes
cytoplasm replaced by keratin
cytoplasm contains: keratin cross-linked with filaggrin (cornified cell envelope)

20

what are the layers of the cornfield cell envelope

extracellular: muti-lamellar lipid layer covalently linked to involucrine
intracellular: involucrine, small proline-rich proteins, loricrin, fillagrin and keratin complex

21

what do tight junctions in the stratum granulosum contain

claudin-1 and claudin-4 (components of the permeability barrier)

22

what are dermis characteristics

dense fibrous irregular CT layer beneath epidermis
derived from embryonic mesoderm
induces development of epidermis and epidermal derivatives
supports epidermis

23

hypodermis characteristics

loose CT that underlies dermis
corresponds to superficial fascia of gross anatomy
technically not part of skin
may contain fat cells that can form a thick layer called the panniculus adiposus

24

what are the 2 layers of the dermi

papillary and reticular layer

25

why are characteristics of papillary layer of ddermis

loose CT
separated from epidermis by basal lamina
network of fine elastic fibers and abundant capillaries

26

what are characteristics of reticular layer of dermis

dense irregular CT
includes fibrocytes, macrophages, and adipocytes

27

where do langerhans cells come from

monocytes

28

where do langerhans cells migrate from and to

migrate from epidermis to lymph nodes

29

where are merkel cells usually located

stratum germinativum

30

what does the periderm slough off to form

vernix caseosa

31

what does the inner cuboidal germinal layer of the epidermis proliferate to form

adult layers of the epidermis and derivatives

32

what is the dermis derived from

mesoderm

33

what are characteristics of sebaceous glands

holocrine glands
branched acinar glands with short ducts
found everywhere except palms and soles
continuously produce sebum (release into hair follicle)
growth is stimulated at puberty by sex hormones

34

what are characteristics of sweat (sudoriferous glands)

both merocrine and apocrine glands

35

what are characteristics of merocrine glands

coiled, simple tubular secretory portions lined by simple epithelium
apical dark secretory cells secrete glycoproteins
basal clear cells secrete water and electrolytes
myoepithelial cells
duct system
cholinergic endings

36

what does the duct system of merocrine glands consist of

stratified cuboidal epithelium except in epidermis

37

where are apocrine glands found

labia majora, areola, and axillary and anal regions

38

where do the excretory duct open into for apocrine glands

hair follicle

39

when do apocrine glands become active

puberty

40

what are the special types of sweat (sudoriferous) glands

ceruminous glands
glands of moll

41

how do apical dark cells secrete glycoproteins

by exocytosis (merocrine secretion)

42

what are the components of a hair follicle

root, free shaft, hair follicle

43

what are characteristics of a hair bulb

expanded lower part of hair follicle
matrix
vascularized dermal papilla

44

what is the external root sheath of hair follicle

down growth of epidermis

45

what is the internal root sheath of the hair follicle generated by

bulb matrix

46

what are the layers of the internal root sheath of hair follicle

Henle's layer
huxley's layer
cuticle (interlocks with cuticle of hair shaft)

47

what are the layers of the hair shaft

medula (innermost)
cortex
cuticle

48

where do the edges of the cuticle of the hair shaft tend to point

downward