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Histology Exam III Material > Integument II > Flashcards

Flashcards in Integument II Deck (63):
1

How thick is the dermis

0.5 to 3 mm thick

2

Dermis corresponds to _______ of a mucous membrane

lamina propria

3

Synonyms for Subcutaneous tissue

-Sub Q
- Superficial fascia
- Hydodermis

4

What is directly related to finger prints

Primary dermal ridge

5

Primary dermal ridge is found everywhere except

forehead, external ear, perineum, and scrotum

6

Primary dermal ridges are formed during

3rd to 4th months of fetal life

7

Primary dermal ridges are subdivided into

two secondary ridges by interpapillary peg

8

What is the interpapillary peg

-It is a downward growth along the crest

- subdivides primary dermal ridge into two secondary dermal ridges

9

Secondary dermal ridges occur in ______ rows, Branched

double

10

Composition of the secondary dermal ridges

Thin collagenous, reticular, and elastic fibers

11

What are dermal papillae

upward projections from each secondary dermal ridge

12

Functions of the integument

-protection from mechanical injury

- Prevents desiccation

- Protects against foreign substances and microorganisms

- Protects against UV radiation

- Thermoregulation

- Regulation of blood pressure (via dermal capillary network)

- Excretion of metabolic waste products

- Synthesis of Provitamin D

13

Integument regulates blood pressure via

dermal capillary network

14

Thick and thin skin refers to the _______ only

epidermis

15

Characteristics of thick skin

-Occurs only on palm and soles and is HAIRLESS
- epidermis varies from 0.4 to 0.6 mm thick
- Displays all five epidermal layers

16

Characteristics of thin skin

- Occurs everywhere except for palms and soles
- epidermis varies form 75 to 150umm thick
- Thinnest skin is on the eyelids
- thickest thin skin is on the back
-thicker on extensor surfaces than flexor surfaces
- epidermal layers less distinct and lacking stratum lucidum

17

Where is the thinnest thin skin

eyelids

18

Where is the thickest thin skin

on Back

19

Epidermal layers of thin skin are _____ and lacking _______

less distinct, stratum lucidum

20

Epidermis is derived from

embryonic ectoderm

21

Layers of epidermis (from deepest to most superficial)

-Stratum basal (germinativum)
-Stratum spinosum (Stratum Malpighi)
-Stratum Granulosum
- Stratum lucidum
- Stratum corneum

22

Langerhans cells are found in what epidermal layer

Stratum spinosum (Stratum Malpighi)

23

The stratum lucidum is absent in

thin skin

24

in thin skin the stratum granulosum is represented by

only a few cells

25

Melanocytes originate in the _____ and are visible form the _____ embryonic week

neural crest, 8th

26

Characteristics of stratum Basale (germinativum)

-Deepest
-Columnar to high cuboidal keratinocytes
- Keratins 5 and 14 (low-molecular weight keratins)
- Single layer of cells
- Held together by desmosomes
- Hemidesmosomes hold layer to basal lamina
- High mitotic activity
- mitotic activity produces stem cells differentiating keratinocytes
- Affected by chemotherapeutic and radiation treatments

27

Characteristics of Stratum Spinosum

-Polyhedra-shaped cells (prickle cells)
- Keratins 1 and 10 (high molecular weight keratins)
- Keratohyalin granules develop
- Membrane-coating granules first appear
-Lamellar bodies
- Contain lipid, carbohydrate, and hydrolytic enzymes
-Tonofibrils
- Form intercellular bridges

28

Characteristics of Stratum Granulosum

-Multilayered
-Keratins 2e and 9
- Flattened nucleated keratinocytes
- Keratohyalin aggregates:
- Fillagrin induces cross-linkage of keratin filaments by disulfide bonds
- no limiting membrane
- Membrane-coating granules (lamellar bodies)
- Acylglucosylceramide---> intercellular spaces
- Tonofilaments

29

General Organization of the Integument

-Epidermis
- Basement membrane
- Dermis
- Subcutaneous tissue
- Epidermal Ridges

30

What keratins are in the stratum basal (Germinativum)

Keratins 5 and 14 (low-molecular weight keratins)

31

Keratin-containing intermediate filaments that form intercellular bridges in the stratum spinosum

Tonofibrils

32

What are Lamellar bodies

-Membrane-coating granules that first appear in the stratum spinosum but are also present in the stratum granulosum
- Contain lipid, carbohydrate, and hydrolytic enzymes

33

Lamellar bodies contain

-lipid, carbohydrate, and hydrolytic enzymes

34

What keratins are present in the stratum granulosum

keratins 2e and 9

35

What keratins are present in the Stratum spinosum

Keratins 1 and 10 (high molecular weight keratins)

36

in what layer of the epidermis do keratohyalin granules develop

Stratum spinosum

37

Stratum lucidum

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

38

Stratum Corneum

-Multilayered (5-50 layers)
- Thicker in thick skin
- Enucleated, flattened, dead keratinocytes
- Cytoplasm replaced by keratin
- cytoplasm contains:
- keratin cross-linked with filaggrin
- cornfield cell envelope

39

Keratin in the stratum corneum is cross-linked with

Filaggrin

40

The cornified cell envelope has a ____ and ____ component

-extracellular
- multi-lamellar lipid layer covalently linked to involucrine
-intracellular
- Involucrine
- Small proline-rich proteins
- Loricrin
- Fillagrin and keratin complexes

41

induces the aggregate of keratins

Filaggrin

42

mutation of Keratin 1 and keratin 10 is caused of

Epidermolytic hyperkeratosis (EHK)

43

Mutation of Keratin 5 and 14 is the cause of

epidermolysis bullosa simplex (EBS)

44

Defects in keratin 2e cause

ichthyosis bulls of Siemens (IBS)

45

A defect of keratin 9 is associated with

epidermolytic palmoplantar keratoderma (EPPK)

46

a specialized structure that reinforces the plasma membrane of keratinocytes

cornfield cell envelope

47

Keratinization

1.) lipids covalently linked to involucrin, thus contributing to the formation of the epidermal permeability barrier.
2.) The cornfield cell envelope is a specialized structure that reinforces the plasma membrane of keratinocytes when they reach their final stage of differentiation. it consists of aggregates of keratins and filaggrin and a complex of three proteins: involucrin, small proline-rich proteins (SPRs), and loricrin, cross-linked by the enzyme transglutaminase K (TGK)
3.) Keratin filaments, aggregated by filaggrin, interact with the inner side of the plasma membrane to form the cell envelope
4.) Tight junctions in the stratum granulosum, containing claudin-1 and claudin-4 are components of the permeability barrier

48

Dermis characteristics

-Dense fibrous irregular CT layer beneath epidermis
- Derived form Embryonic mesoderm
- Induces development of epidermis and epidermal derivatives
- Supports epidermis

49

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 panicles adiposus

50

What are the two layers of the dermis

-Papillary layer (closest to the epidermis)
- Reticular layer

51

Composition of the papillary layer of the dermis

- Closest to the epidermis
- Loose CT
- Separated form epidermis by basal lamina
- Network of fine elastic fibers and abundant capillaries

52

The papillary layer is separated form the epidermis by the

basal lamina

53

Composition of the Reticular layer of the dermis

-Dense irregular CT
- Includes fibrocytes, macrophages, and adipocytes

54

Langerhans cells

-dendritic cells
- Derived from monocytes
- Antigen-presenting cells
-primarily in the stratum spinosum
- Migrate from epidermis to lymph nodes
-Birbeck granules

55

Langerhans cells interact with keratinocytes through

E-Cadherins on their surface

56

Birbeck granules

Found in langerhans cells
contain the proteins langerin and CD1a (cell surface marker), involved in the uptake and delivery of antigens

57

Merkel Cells

-Mechanoreceptors
- May also act as diffuse neuroendocrine cells
-Usually in stratum germinative (basale)
-Contain catecholamine-like granules

58

Melanocytes

-Derived from melanoblasts
-Do not form desmosome attachements in epidermis
- Inject melanin granules into keratinocytes
- Pathway for melanin formation:
- Tryrosin--> 3,4-dihydroxyphenylalanine (DOPA) --> dopaquinone--> melanin
- Requires tyrosinase

59

What is the pathway for melanin formation

-tyrosin---> 3,4 dihydroxyphenylalanine (DOPA)---> dopaquinone---> melanin
- *** requires tyrosinase*****

60

Development of the integument

- Epidermis starts as a single layer of ectodermal cells
- divide during the sixth week to form:
- Periderm
-Sloughs off to form vernix caseosa
- Inner cuboidal germinal layer:
- Continues to proliferate to form adult layers of the epidermis and derivatives:
- 10 weeks: fingernails
- 12 weeks: Hair buds and toenails
-Dermis is derived from mesoderm

61

Tactile receptor present in dermal papilla

Meissner's corpuscle (note that they are present in fingers, hand, foot, front of forearm, lips, and tongue)

62

Merkel cells are usually located in

The stratum Germinativum

63

Do melanocytes form desmosome attachments in epidermis

No