Immune System

Question 1

What are the 3 main roles of the lymphatic system?

Answer 1

1. Maintain fluid balance
2. Transport lipids
3. Protect against infection

Question 2

What are pathogens?

Answer 2

Microscopic organisms that can cause harm to the body

Question 3

What is the defense system?

Answer 3

A system that activates when pathogens enter your system in order to protect against the pathogens

Question 4

What are the 3 lines of defense?

Answer 4

1. Barriers
2. Non-specific defenses
3. Specific defenses

Question 5

Describe the 1st line of defense

Answer 5

Surface barriers that prevent pathogens from entering the body

Question 6

What are the different components of the 1st line of defense?

Answer 6

1. Physical: eyelashes, cilia in respiratory tract, nose hairs
2. Chemical: mucus, tears, stomach acid, precipitation
3. Skin: hostile environment for microorganisms

Question 7

Describe the 2nd line of defense

Answer 7

• The non-specific cellular and molecular responses of the immune system (does not involve antibodies)
• Defences do not differentiate between different pathogens (respond the same way for each infection)

Question 8

What are the different components of the 2nd line of defense?

Answer 8

1. Natural killer cells (target cancerous or infected body cells and perform phagocytosis: engulf foreign bodies)
2. Inflammatory response (damage to tissue causes release of histamine and cause capillaries to swell and leak, releasing phagocytes)
3. Fever (WBCs release chemicals, triggering the hypothalamus to increase body temperature,
   causing WBCs to work better and viruses/bacteria to weaken

Question 9

Describe the third line of defense

Answer 9

• During fetal development the body makes a list of all “self” particles (antigens that belong)
• Antigen receptors (same shape as antibodies) on B and T cells recognize foreign antigens, and bind to them and neutralize them
• If we come into contact with the same antigen again, the immune response will be faster

Question 10

What are T-cells?

Answer 10

They are lymphocytes (a type of WBC) that develops in the thymus gland. They recognize pathogens and activate immune responses

Question 11

What are the different types of T-cells?

Answer 11

Helper T cells
Killer T cells
Suppressor T cells
Memory T cells

Question 12

What do helper T-cells do?

Answer 12

Recognize antigen from chemical signals and stimulate more phagocytes/macrophages, B cells, and T cells

Question 13

What do killer T-cells do?

Answer 13

Bind, puncture, and destroy infected cells; essentially “self-destruct”

Question 14

What do suppressor T-cells do?

Answer 14

Slows/turns off immune response to protect healthy tissues after invader is killed off

Question 15

What do memory T-cells do?

Answer 15

Do not respond on first exposure, but remember pathogen and remain in blood for future invasion

Question 16

What are B-cells?

Answer 16

They are lymphocytes (a type of WBC) that mature in bone marrow. When they are activated, the cell enlarges and divides into memory B and plasma cells

Question 17

What is the role of a plasma cell?

Answer 17

Produce and release large amounts of antibodies (200/sec) that will match the foreign invader’s antigen and bind to it, disabling the pathogen

Question 18

What is the role of a Memory B-cell?

Answer 18

Remembers the pathogens after the infection is gone, and stays in blood ready for them to attack again

Question 19

What is an autoimmune disorder?

Answer 19

When T cells or antibodies mistakenly attack the body’s own cells

Question 20

What are allergies? What are the two types?

Answer 20

Exaggerated immune response to a harmless material. The two types are acute and delayed

Question 21

Describe an acute allergy

Answer 21

Reaction occurs within seconds;
antibodies trigger release of histamines, causing swelling, watery eyes, runny nose, etc.