Final: Immunology: Animal Defense Systems Slides

Question 1

Immune system functions

Answer 1

1. Protect against infection and microbes (invasion of pathogens)
2. Destroy pathogens that do enter the body

Question 2

How can pathogens enter the body?

Answer 2

Openings (nose, mouth, etc.) or if skin gets cut

Question 3

What are pathogens and where are they found?

Answer 3

Unwanted material; found literally everywhere

Question 4

What are types of pathogens (5)?

Answer 4

Parasites (multicellular worms), bacteria (prokaryotes), protists (unicellular), fungi, virus (nonliving)

Question 5

Types of immune response

Answer 5

Nonspecific (general, first response) and specific (specific to one pathogen)

Question 6

Barriers to infection (3)

Answer 6

Physical barriers, chemical barriers, reflexes (sneeze, cough, etc.)

Question 7

Examples of physical barriers (3)

Answer 7

Skin (best example), fibrous layer of eyes, mucous membranes (of respiratory, digestive, urinary, reproductive systems, and of ears)

Question 8

What makes skin a good physical barrier?

Answer 8

Outermost skin cells are essentially dead; they make so much keratin that they can’t function

Question 9

Examples of chemical barriers (9)

Answer 9

Sebum, mucus, saliva, sweat, cilia, macrophages, lacrimal glands, wax, stomach acid

Question 10

Sebum

Answer 10

Oily acidic substance released from sebaceous glands (skin); affects osmolarity of pathogens

Question 11

Lysozymes

Answer 11

Enzymes secreted from the mucous membranes (found in tears, saliva, etc.)

Question 12

Defensins

Answer 12

Peptides secreted from the mucous membranes (found in saliva, etc.)

Question 13

Lymphoid tissue function

Answer 13

Clusters of organs that make immune cells (to be released to circulation) or are where immune cells are stationed

Question 14

Examples of lymphoid tissues (7)

Answer 14

Adenoids, tonsils, thymus, lymph nodes, spleen, lymphatic vessels, bone marrow

Question 15

What occurs in bone marrow?

Answer 15

Many types of immune cells grow, mature, and are released into the circulation

Question 16

Immune cell function

Answer 16

Attack and destroy pathogens

Question 17

Neutrophil function

Answer 17

Destroy pathogens through phagocytosis (most abundant phagocytic cells) and release cytokines, vasodilators, and chemotaxins

Question 18

Cytokine function

Answer 18

Increase alertness, recruit other immune cells

Question 19

Vasodilator function

Answer 19

Increase blood vessel diameter to make circulation easier (immune cells use blood vessels to travel)

Question 20

Chemotaxin function

Answer 20

Direct immune cells to site of need

Question 21

Difference between monocytes and macrophages

Answer 21

Monocytes when in circulation; macrophages are functional monocytes, once recruited and ready to attack

Question 22

Macrophage functions (2)

Answer 22

-Engulf and digest pathogens (phagocytose/endocytose)
-Activate T cells (by releasing cytokines)
(do these simultaneously: attack while calling for backup)

Question 23

Mast cell location

Answer 23

Throughout connective tissues (not in blood)

Question 24

Mast cell function

Answer 24

Release histamine (type of signal cytokine) and other chemicals to recruit immune cells - not in direct contact with pathogens

Question 25

B lymphocyte functions (2)

Answer 25

• Transform into plasma cells and release antibodies into circulation
• Form memory cells

Question 26

How do antibodies help immune response?

Answer 26

Tag pathogens so other immune cells can destroy them

Question 27

What are memory B cells?

Answer 27

Produce antibodies that remember specific pathogens for a faster, more efficient attack

Question 28

Cytotoxic T cell functions

Answer 28

• Release perforin and granzymes directly into target cell

- Induce apoptosis by activating Fas receptor

Question 29

Granzyme function

Answer 29

Digest or break down pathogen

Question 30

General sequence of immune response (4 steps)

Answer 30

1. Phagocytosis and recruitment
2. Vasodilation and increase in permeability
3. Phagocytic cells migration
4. Tissue repair

Question 31

What do injured cells release?

Answer 31

Chemotaxin (or chemoattractants), which attracts immune cells and tells them where to go

Question 32

Why does swelling occur at site of injury?

Answer 32

Vasodilation means increased blood vessel permeability, so stuff normally supposed to be in blood vessel leaks to extracellular space

Question 33

Which cells line blood vessels?

Answer 33

Endothelial cells

Question 34

Effects of vasodilation (caused by histamine) (4)

Answer 34

• Increase in blood flow to infected areas
• Redness
• Increased protein delivery
• Edema (swelling)

Question 35

Margination

Answer 35

Macrophages en route to injury site match receptors with endothelial cells (so they know where to exist blood vessel)

Question 36

What are the receptors and attachment process for cytokines and phagocytic cells?

Answer 36

Cytokines signal endothelial cells to express selectin; phagocytic cells produce integrin (facilitates attachment)

Question 37

Diapedesis

Answer 37

Phagocytic cells move from blood to infected area (attracted to specific injury site by chemotaxins)

Question 38

Steps of phagocytosis

Answer 38

1. Attachment (receptors match)
2. Internalization (phagosome fuses with lysosome)
3. Degradation in phagolysosome
4. Exocytosis
   - process of intracellular digestion/destruction

Question 39

What is a phagolysosome?

Answer 39

Enzymes of lysosome fuse with phagosome

Question 40

What is the process of attachment called in phagocytosis?

Answer 40

Opsonization (physical binding)

Question 41

What is an example of extracellular destruction?

Answer 41

Membrane Attack Complex (MAC) - complement system

Question 42

How does MAC work?

Answer 42

Series of proteins that embed themselves on pathogen membrane surface, triggering event cascade of protein activation that leads to insertion of pores in pathogen membrane - pathogen cell swells as water and salt enter, and lysis (bursting) occurs