Barriers

Question 1

Which immune system are barriers a part of?

Answer 1

Innate

Question 2

Where are the vast majority of the body’s immune resources directed towards?

Answer 2

Barriers

Question 3

Epithelial tight junctions

Answer 3

Specific cell adhesion

Question 4

There are many layers to the epithelium. Each layer has a function. What are three?

Answer 4

Shedding
Tight junctions
Lipid layer

Question 5

Cilia

What are they? Where are they? What do they do?

Answer 5

Active, hair-like structures
The apical surface of airway epithelium
Sweep and propel mucus

Question 6

What can lead to the dysfunction of Cilila?

Answer 6

Smoking

Smokers cough

Question 7

What does Cilia not work without?

Answer 7

MUCUS

Question 8

Does the GI tract have cilia?

Answer 8

NO
Just mucus
Sheds/sloughs

Question 9

What is mucus comprised of?

Answer 9

Glycoprotein and water

Question 10

A mucus dysfunction leads to what illness?

Answer 10

Cystic Fibrosis

Question 11

What is Cystic Fibrosis?

Answer 11

A mutation in a chloride pump that cannot regulate

Makes mucus think - no air exchange

Question 12

What three things does the barrier system reinforce with?

Answer 12

Chemicals (acid)
Enzymes (lysosome)
Molecular (defensins, IgA)

Question 13

4 chemical mechanisms that help barrier

Answer 13

Stomach acid - pH 2 - ACID
Skin - slightly acidic, glands secrete lipids
Salts in sweat make it hypertonic
Intestine - pH above 7 - ALKALINE

Question 14

The enzymatic molecule that helps with barrier

Answer 14

Lysozyme

Question 15

Where can you find lysozyme?

Answer 15

Tears, saliva, milk, GI mucus

Question 16

What does lysozyme do?

Answer 16

Catalyzes the breakdown of peptidoglycan in bacterial cell walls

Question 17

Does lysozyme need to be specific?

Answer 17

No, we don’t have a sugar base cell wall

Question 18

What 3 molecular defenses coat barrier surfaces?

Answer 18

a-defensin
b-defensin
antibodies (IgA)

Question 19

What are defensins?

Answer 19

tiny - 30 aa peptides

Question 20

How do we produce defensins and in what form?

Answer 20

Produced by epithelial cells, paneth cells, and neutrophils

In an inactive form

Question 21

What can upregulate defensins?

Answer 21

cytokines

Question 22

two ways the defensin direct antimicrobial activity?

Answer 22

Disrupt membranes

Impair DNA/RNA synthesis

Question 23

How are defensins activated?

Answer 23

proteolytically cleaved

Question 24

What does defensin activate?

Answer 24

Leukocytes

Question 25

a-defensins
Where?
How are they produced and released? 2 ways
What do they do?

Answer 25

found in mucosal secretions
paneth cells –> gut mucosa
neutrophils –> stored in granules
Direct anti-microbial activity

Question 26

b-defensin
Produced?
Stored?
What do they do?

Answer 26

Skin epithelial cells
stored in lipid-rich lamellar bodies
Lamellar bodies produce a water-proof barrier on the skin

Question 27

What is a dedicated molecule to remove IgA?

Answer 27

Immunoglobulin

Question 28

Normal flora

What? Where?

Answer 28

Non-pathogenic commensal bacteria

Most barriers are coated

Question 29

How does the Normal flora help with immunity? 3 things

Answer 29

Occupy space - preventing attachment
Stimulate defensin and IgA
Maintain immune tolerance