The Immune System and Innate Defenses Study Guide

Question 1

Pathogen

Answer 1

a potentially harmful microbe-bacteria, viruses, fungi etc

Question 2

organs or tissues borrowed from other systems and used for their immune functions

Answer 2

Skin, spleen, tonsils, bone marrow, thymus, lymph nodes, mucous membranes

Question 3

1st line of defense

Answer 3

a surface barrier
- skin
- mucous membranes
- secretions of skin and mucous membranes

Question 4

2nd line of defense

Answer 4

internal defenses that act when the 1st line is broken
- phagocytic cells
- natural killer cells
- antimicrobial cells
- inflammatory response
- fever

Question 5

3rd line of defense

Answer 5

slower to mount but acts with more precision and efficacy
- lymphocytes
- antibodies
- macrophages and other antigen-presenting cells

Question 6

protective chemicals from the 1st line of defense

Answer 6

• Acid to inhibit bacterial growth
• Enzymes (Example: Lysozyme) to destroy bacteria
• Mucin to trap microbes
• Defensins to control bacterial growth in exposed areas

Question 7

4 cardinal signs of inflammation

Answer 7

Redness, heat, swelling, and pain

Question 8

What types of leukocytes are phagocytes

Answer 8

Neutrophils are the most abundant phagocytes

Question 9

What purposes does inflammation serve?

Answer 9

• Prevent the spread of damaging agents to the nearby tissue
• Dispose of cell debris and pathogens
• Alert the adaptive immune system
• Set the stage for tissue repair

Question 10

what types of leukocytes are Natural Killer Cells?

Answer 10

NK cells are a type of lymphocyte that are less picky than the ones of the adaptive immune system – they can kill cancerous/virus infected cells before adaptive immune system is activated

Question 11

type of leukocyte that can differentiate into a macrophage when activated

Answer 11

monocytes

Question 12

opsonization and why it’s useful

Answer 12

• “To make tasty” – accelerates phagocytosis
• The immune system coats a pathogen with opsonins – complement proteins or antibodies – to obtain a place to bind – the opsonins allow the phagocyte and the pathogens to bind

Question 12

cell organelle that plays a key role in phagocytosis

Answer 12

Lysosomes and phagosomes (form lyso-phagosomes)

Question 12

steps of phagocytosis

Answer 12

1. Phagocyte adheres to pathogens
2. Phagocyte engulfs the particles, forming a phagosome
3. Lysosome fuses with the phagocytic vesicle, forming a phagolysosome
4. Lysosomal enzymes digest the pathogens or debris, leaving a residual body
5. Exocytosis of the vesicle removes indigestible and residual material

Question 13

When pathogens cannot be killed with lysosomal enzymes ….

Answer 13

Helper T Cells trigger macrophages to produce “respiratory burst” - cell-killing free radicals, oxidizing chemicals, pH/osmolarity changes

Question 14

two functions of a fever

Answer 14

They sequester iron and zinc – minerals needed to support bacterial growth – and increasing the metabolic rate of tissue cells completing repair processes

Question 14

3 inflammatory mediators

Answer 14

Histamine, kinins, prostaglandins (like nitric oxide), complement proteins

Question 15

phagocyte margination

Answer 15

Phagocytes cling to the inner walls of capillaries and postcapillary venules to indicate the place of injury

Question 16

type of antimicrobial protein most effective against viruses

Answer 16

Interferons are most effective against viruses – they are secreted by virus infected cells and protect nearby uninfected cells by slowing down protein synthesis

Question 17

type of antimicrobial protein most effective against bacteria

Answer 17

Complement proteins are most effective against bacteria – they are a group of about 20 plasma proteins circulating the blood, when activated they will amplify nearly all aspects of the inflammatory process, and they can lyse (kill) certain cells and bacteria

Question 18

What is the body’s internal thermostat and the substance that is involved in the body’s temperature?

Answer 18

The hypothalamus is the body’s thermostat – pyrogens act on it to raise the body’s temperature