Chapter 14: The innate Immune Response + 1st Line

Question 1

What does innate immunity refer to?

Answer 1

• defenses that are present at birth

Question 2

Innate immunity is non-specific, which means what?

Answer 2

• act against all (most) microbes in the same way!

Question 3

Does innate immunity have memory?

Answer 3

No, it cannot recall previous contact with an invader

Question 4

Is innate immunity always present? (2)

Answer 4

• yes, it is active before an infection occurs
• responds rapidly

Question 5

What is the first line of defense?

Answer 5

Physical and chemical barriers that prevent microbes from entering the body
- sweat, mucous, saliva, hair, etc.

Question 6

What is the second line of defense?

Answer 6

• components that act to eliminate microbes that have invaded body tissues

Question 7

what does the second line of defence include? (3)

Answer 7

• Cellular defenses
• molecular defenses (enzymes, protein, etc)
• fever and inflammation

Question 8

for the first line of defense, what are the three physical barriers?

Answer 8

• skin
• mucous membrane
• fluid flow

Question 9

what is the outer layer of skin consist of?

Answer 9

• cells and keratin (protective protein)

Question 10

What are some characteristics of skin? (2)

Answer 10

• frequently shed to remove microbes
• dry to inhibit microbial growth, hence skin infections are more common on moist areas of skin

Question 11

why is the outer layer of skin an excellent defense? (2)

Answer 11

• rarely penetrated by microbes
• that is why most infections occur under the skin, after it has been broken

Question 12

what is the cause of body odor?

Answer 12

Microbes are able to eat dead skin cells and oils secreted by the skin

Question 13

what are the mucous membranes involved in? (2)

Answer 13

• Involved in fluid or gas exchange
• offer less protection than the skin

Question 14

What do the mucus membranes line?

Answer 14

Lines our tracts, such as the digestive tract

Question 15

what do the mucous membranes secrete and why? (2)

Answer 15

• secretes mucus, a glycoprotein, that keeps membranes from drying (cracking)
• traps microbes

Question 16

what is the purpose of the mucociliary escalator?

Answer 16

cilia sweep mucus away
ex. in lungs, to move microbes out

Question 17

what is fluid flow, and what is its purpose?

Answer 17

• Saliva, tears, urine, vaginal secretions
• microbes away from the body

Question 18

for the first line of defense, what are the five chemical barriers (antimicrobial)? (5)

Answer 18

1. Acidity of body fluids and skin
2. Lysozyme
3. Lactoferrin
4. Defensins
5. The normal microbiota

Question 19

how is acidity of body fluids and skin a first line of defense? (3)

Answer 19

• stomach acid has a pH of 2, which destroys many bacteria and toxins
• skin has fatty acids and lactic acid with a pH of 3 to 5
• prevent the growth of many microbes

Question 20

What are lysozymes? (3)

Answer 20

• enzymes that degrade peptidoglycan
• in sweat, tears, saliva, nasal secretions
• lecture, it makes gram-positive cells more susceptible

Question 21

What is lactoferrin?

Answer 21

• Iron binding proteins in milk, mucus

Question 22

What is the purpose of lactoferrin? (2)

Answer 22

• makes iron unavailable to slow growth of microbes
• in lecture, in is essential for bacteria

Question 23

What are defensins? (3)

Answer 23

• short polypeptides
• poke holes in microbial membranes
• produced by epithelial cells

Question 24

how is the normal microbiota a first line of defense? (3)

Answer 24

• acquired shortly after birth
• prevent growth of pathogens
• competitive exclusion and microbial antagonism