Immune System

Question 1

What are (3) roles of the immune system?

Answer 1

1- defense against microbes

2-defense against growth of tumour cells

3-kills growth of tumour cells

Question 2

Two types of immunity?

Answer 2

• innate immunity

-adaptive immunity

Question 3

Two major functions of immunity?

Answer 3

1-prevention & control of infections u til adaptive immune responses are activated
2- stimulation of adaptive immune responses to be effective

Question 4

Similarities between inniate & adaptive immunity?

Answer 4

Cells: both mediated immunity

Humoral: medicated immunity

Question 5

What is a monocyte?

Answer 5

Young microphage in the blood

Killing of microorganisms

Question 6

Describe what centric cells are and where they are found?

Answer 6

Activation of T cells and initiate adaptive immunity

Found mainly in Lymphoid tissue

Function as antigen presenting cells (APC)

Question 7

What are mast cells?

Answer 7

Expulsion of parasites through the release of granules
(Histamine, leukotrienes, chemokines,cytokines)

Also involved in allergic reaction

Question 8

What is the job of a neutrophil?

Answer 8

Very important at clearing bacterial infections

Short life spans (hours)

Question 9

What is the function of eosinophils?

Answer 9

Kills AB-coated parasites through degranulagion

Involved in allergic inflammation

Double lobed nucleus

Question 10

What is a basophil?

Answer 10

A cell-killing cells

Contain toxic and inflammatory compounds

Important in allergic reactions

Question 11

Outline the 7 stages of phagocytosis;

Answer 11

(1) chemotaxis and adherence of microbe to phagocyte

(2) ingestion of microbe by phagocyte

(3) formation of a phagosome

(4) fusion of the phagosome with a lysosome = phagolysosome

(5) digestion of ingested microbe by enzymes

(6) formation of residual body containing indigestible material

(7) discharge of waste materials

Question 12

Give 2 examples of antigen presenting cells;

Answer 12

• macrophages
• dendritic cells

Question 13

Give 3 examples of functional classifion of innate cells;

Answer 13

1) phagocytes cells

2) antigen presenting cells (APCs)

3) direct attack cells

Question 14

Outline cells of myeloid origin;

Answer 14

Monocytes & macrophages

Granulocytes

Question 15

Outline the type of cell of lymphoid origin;

Answer 15

Natural killer (NK) cells

Question 16

Describe natural killer cells;

Answer 16

Ready to kill the target cells; not require activation

Question 17

What two killing mechanisms are involved in natural killer cells and describe them;

Answer 17

(1) perforin - insertion of pores into the cell membrane

(2) granzyme - released from granules into the target cells through the pores and induce apoptosis

Question 18

Regulation via inhibitory and activating receptors;

Answer 18

• different from PRRs
• inhibitory receptors suppress killing activity
• activating receptors enhance already existing cytotoxicity

Question 19

What is the function of B-lymphocytes?

Answer 19

Each B cell is genetically programmed to produce an antibody of unique specificity

Question 20

What are two types of T lymphocyte?

Answer 20

T helper cells

Cytotoxic T lymphocytes

Question 21

What do T helper cells express?

Answer 21

• express cytokines to coordinate the immune response
• express T cell receptor (TCR) and CD4 Co-receptor
  • Th1 and Th2

Question 22

Describe cytotoxic T lymphocytes;

Answer 22

• express T cell receptor (TCR) and CD8 Co-receptor

• destroy infected cells directly