44-Skin as a Protective Barrier Flashcards Preview

Immunology > 44-Skin as a Protective Barrier > Flashcards

Flashcards in 44-Skin as a Protective Barrier Deck (57)
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1

Functions of skin

Fluid and electrolyte homeostasis
Protect from toxic substances
Protect from trauma
Thermoregulation
Metabolic functions
Protect from infection
Protect from UV light

2

What is keratinization

Process of cell maturation to form flexible protective barrier

3

Characteristics of keratinization

Genetically programmed
In post mitosis keratinocytes
Morphologic changes
Regulated by extrinsic and intrinsic factors
Vulnerable to alteration

4

The steps of epidermal differentiation

alterations of plasma membrane antigens and receptors
Degradation of organelles
Cellular dehydration

5

What is the stratum corneum

semipermeable barrier to water and electrolytes
Protects internal environment

6

structure of stratum corneum

bicompartment of hydrophilic protein cells (corneocytes) surrounded by hydrophobic intercellular lipid matrix

7

What are corneocytes

metabolically inert
enucleated cells formed from keratinocytes

8

What is the cornified envelope

Component of corneocytes, cross linked proteins catalyzed by transglutaminase 1
loricrin, involucrin, keratolinin

9

What are the proteins in the cornified envelope

loricrin, involucrin,keratolinin

10

What catalyzes the cornified envelope cross linked proteins

transglutaminase 1

11

What surrounds the cornified envelope

lipid envelope

12

What makes the intercellular lipid matrix

lamellar granules from keratinocytes organelles

13

Where are lamellar granules found

Between the granular layer and the stratum corneum

14

What do the lamellar granules do

Fuse with membrane and discharge lipid contents

15

What are the major membrane lipids of stratum corneum

ceramides
Impermeable to water

16

What do epidermal lipids do

form cement to hold corneocytes together

17

what is in lamellar granules/Orland bodies

lipids

18

What is in keratohyalin granules

protiens

19

Where are lamellar/Odland found

Upper spinous, layer, granular cornified layer interface

20

Where are keratohyalin granules found

Upper spinous layer,
Granular and cornified layers

21

Do lamellar/Odland have membranes

Yes, membrane bound

22

Do keratohyalin have membranes

No, not membrane bound

23

What is the function of lamellar/ Odland

deliver precursors of corneum lipids
Lipids accumulate in lamellar granules and fuse with plasma membrane to exocytose lipid to intercellular space

24

What is the function of keratohyalin granules

deliver free amino acids to corneum (filaggrin monomers)
Conversion of profilaggrin to filaggrin

25

What cannot pass through corneum

Polar or large molecules (MW > 800-1000)

26

How does corneum protect from trauma

Strong stratum corneum
Highly resistant cornified envelope
corneocytes are interdigitated
desmosomes
corneum is elastic
Low conductivity-protection from electrical and thermal damage
Nerve sensations

27

What is core body temp

37

28

What temps can skin vary between without damage

20-40

29

How does body thermoregulate

Blood vessel and eccrin glands

30

What does the body do in cold environment

Use sympathetic to contract vessel, decrease peripheral flow and conserve central body heat