Lymphoid System

Question 1

What is the first line of defense?

Answer 1

Physical/Biochemical Barriers

Question 2

What is the second line of defense?

Answer 2

Innate (non-specific) immunity

Question 3

What is the third line of defense?

Answer 3

Acquired (specific) immunity

Question 4

What are the cells that participate in innate immunity?

Answer 4

1. mastocytes
2. leukocytes
   
   • granulocytes
   • neutrophil
3. Agranulocytes
   
   • monocytes
   • macrophage
   • natural killer lymphocytes

Question 5

Neutrophils act by?

Answer 5

phagocytizing and destroying bacteria

Question 6

Eosinophils participate in?

Answer 6

allergic reactions and parasitic (worm) invasion

Question 7

Characteristics of Natural Killer Cells

Answer 7

1. surgical stress reduces NK cell numbers and function
2. post-operative loss of NK cell numbers and function is greatest three days and recovers by one month
3. Loss of NK cells may allow enhanced seeding of metastatic

Question 8

Characteristics of Acquired (specific) Immunity

Answer 8

• involves macrophage
• B cells will mediate humoral cells
• cell mediated immunity to T cells

Question 9

Function of the Lymphoid System

Answer 9

Protection and Immunity

• Antigen recognition: must distinguish self vs. non-self
• Antigen Inactivation/Elimination (“the immune response”)
  
  1. Foreign Material
  2. Microorganisms
  3. Cancer Cells
  4. Organ Transports

Question 10

Types of Acquired Immunity

Answer 10

1. Humoral
   
   • B cell lymphocytes
2. Cell Mediated
   
   • T cell lymphocytes

Question 11

Humoral Immune System

Answer 11

• production of antibodies
• The antigen of the microorganism reacts with antibodies present on the surface of B lymphocytes, activating them. These activated lymphocytes proliferate and differentiate into memory B lymphocytes and plasma cells, which secrete antibodies to neutralize the invading microorganism.

Question 12

Cellular Immune System

Answer 12

• Cytotoxic (cytolytic) T lymphocytes are activated by contact with an infected cell that presents complexes of viral antigens with MHC-I molecules on its surface. This activation results in the production of cytotoxic memory T lymphocytes and T cytotoxic lymphocytes, which produce perforin that lyses the infected cell

Question 13

Characteristics of Humoral Immunity

Answer 13

• B cell orgin and development
  
  • Bone Marrow
• Plasma Cells
• Antibody (immunoglobulin)
• humoral response

Question 14

Characteristics of Plasma Cells “Antibody Factories”

Answer 14

• produce and secrete ABS
• terminally differentiated
• survive weeks to months
• RER in plasma cells are producing immunoglobulins

Question 15

IgG

Answer 15

• monomere
• 80%
• site: Blood, lymph intestinal lumen
• function: acivates phagocytosis, neutralizes antigens, protects newborns

Question 16

IgM

Answer 16

• pentamere
• 5-10%
• site: B lymphocytes surface
• function: first antibodies to be produced in an initial immune response

Question 17

IgA

Answer 17

• Dimer with secretory component
• 10-15%
• site: produced in B lymphocytes of the lamina propia and presents as dimers insecretions (saliva, milk, tears,etc)
• function: protects the surface of mucosas for it resists proteolysis

Question 18

IgD

Answer 18

• monomere
• 0.2 %
• presents only on the surface of B lymphocytes
• function: as a receptor to antigens triggered B cell antigen

Question 19

IgE

Answer 19

• monomere
• 0.002%
• site: Bound to the surface of mastocytes and basophils
• function: participates in allergy and lyses parasitic worms