Part 3: Innate Immunity

Question 1

Barriers that separate and shield the interior of the body from the surrounding environment

Answer 1

First line defenses

Example: skin, mucous membranes, antimicrobial substances, normal flora/microbiota

Question 2

What it is the most difficult barrier (in the first line defenses) for microbes to penetrate and why?

Answer 2

The skin because dermis is tightly woven fibrous CT and the epidermis is composed of many layers of epithelial cells that become more flattened toward the exterior

Question 3

What barrier (of the first line defenses) lines intestinal tract, respiratory tract, and genitourinary tract?

Answer 3

Mucous membranes

Question 4

What kind of immunoglobulin is in mucus?

Answer 4

IgA

Question 5

What kind of barrier (of first line defenses) includes both skin and mucous membranes the produce substances that kill or inhibit the growth of microorganisms?

Answer 5

Antimicrobial substances

Question 6

What kind of antimicrobial substance evaporates and leaves a salty residue?

Answer 6

Sweat

Question 7

What kind of antimicrobial substance is an enzyme found in tears, saliva and respiratory secretions? And what does it do?

Answer 7

Lysozyme; degrades peptidoglycan (so its more effective against Gram positive)

Question 8

What kind of antimicrobial substance kills many ingested bacteria?

Answer 8

Acid in stomach

Question 9

What type of barrier (first line defense) is populations of microbes routinely found growing on the body surfaces of healthy individuals?

Answer 9

Normal flora/microbiota

Question 10

What is the genome/DNA of microbial symbionts?

Answer 10

Microbiome

Note: if normal flora is not present, underlying tissue is more vulnerable

Question 11

When the first line barriers are breached, there are two sensor systems within the body:

Answer 11

1. Toll-like receptors

2. Complement

Question 12

Toll like receptors allow cells to send chemical messages called:

Answer 12

Cytokines

Question 13

Cells that specialize in engulfing and digesting microbes are known as

Answer 13

Phagocytes

Question 14

Two classes of phagocytes that participate in innate immune response

Answer 14

• Macrophage

- Neutrophils

Question 15

What is the killing strength of macrophages and neutrophils?

Answer 15

Naive macrophage < neutrophil < activated macrophage

Question 16

What kind cell kills tumor cells but does not phagocytize and instead injects performing proteins to cause holes in target cell?

Answer 16

Natural Killer cells

Question 17

Every “self” cell has the same surface protein called

Answer 17

MHC 1

Note: current thinking is that this is how NK cells identify their target cell

Question 18

What is the inflammation response generated by innate immune system?

Answer 18

1. Injury
2. Dilation of blood vessels
3. Fever

Note: complement proteins assist in sensing invasion
Note: fever is due to cytokines called interleuken-1 (IL-1)