Topic 2: Innate Immunity I

Question 1

What is innate immunity?

Answer 1

non specific defenses

Question 2

What is the 1st line of defense?

Answer 2

skin, mucous membranes, chemicals

Question 3

What is the 2nd line of defense?

Answer 3

phagocytosis, complement, interferon, inflammation, fever

Question 4

What is adaptive immunity

Answer 4

specific defenses

Question 5

What is the 3rd line of defense?

Answer 5

lymphocytes, antibodies; specific antigens for specific pathogens

Question 6

What are the three fundamentals of innate immunity?

Answer 6

1. protective mechanism that exists before infection
2. rapid responses encoded within the germline (DNA in egg and sperm cells)
3. responses are typically identical upon repeat infection

Question 7

What is inflammation

Answer 7

mobilizing bodily defenses at sites of infection

Question 8

How does inflammation work

Answer 8

• Vasodilation: capillaries expand and blood fills these capillaries with RBC
• increase in capillary permeability
• influx of immune cells to affected tissues

Question 9

What are the 4 signs of inflammation?

Answer 9

• Redness: vessels dilate (vasodilation) + blood volume increases
• Heat: increased blood volume brings warmth to affected tissue
• Edema: swelling due to accumulation of fluid from blood in affected tissue
• Pain: some inflammatory mediators trigger the pain response

Question 10

What is special about the vasodilated areas in the capillaries

Answer 10

It has slower blood flow and blood has increased contact with capillary walls

Question 11

What are phagocytes?

Answer 11

“cells that eat”, they ingest and destroy microbes by a process known as phagocytosis ex. macrophages, monocytes and neutrophils

Question 12

What are the two process used by phagocytes

Answer 12

1) Chemotaxis: chasing down of microbes
2) Phagocytosis: eating of microbes

Question 13

What are the steps of phagocytosis?

Answer 13

1. Phagocytes detects and engages microbe
2. Microbe engagement initiates cytoskeletal rearrangements that drive phagocytosis
3. The microbe is internalized in a specialized phagosome
4. The phagosome fuses with the lysosome to form a phagolysosome
5. Lysomal enzymes destroy ingested microbes through the creation of oxidative molecules that can destroy pathogen cell walls
6. Reactive oxygen and nitrogen intermediates destroy microbial proteins, genomes and walls

Question 14

How does the lysosome protect our body’s essential proteins from reactive oxygen and nitrogen intermediates

Answer 14

The reactive oxygen and nitrogen are only present in the luminal section of lysosome which protects our bodies

Question 15

How are macrophages formed?

Answer 15

1. Macrophages arise from undifferentiated stem cells in the bone marrow
2. Some stem cells differentiate into short lived monocytes that circulate the blood
3. Inflammation recruits monocytes to sites of infection where they differentiate into resident macrophages
4. Resident macrophages are long-lived “professional” phagocytes that ingest large amounts of extracellular material

Question 16

Fill in the blank: Phagocytes don’t just eliminate microbes. They activate neighbouring cells through the release of _______ and _________

Answer 16

cytokines;chemokines

Question 17

What are cytokines

Answer 17

secreted proteins that drive immune and inflammatory reactions. In innate immunity, cytokines are produced by macrophages and natural killer cells

Question 18

What is one effect of cytokines

Answer 18

they induce proteins in the endothelium that make the endothelium more adherent for passing leukocytes

Question 19

What are chemokines

Answer 19

a large family of structurally related, low molecular weight cytokines that stimulate leukocyte movement and regulate the migration of leukocytes from the blood to tissues

Question 20

How is chronic inflammation linked to the whole body?

Answer 20

Chronic inflammation can affect various aspects of the body that can lead to significant disorders and death.