Introduction

Question 1

what are the various defence challenges face by the immune system?

Answer 1

1) wide variety of pathogens
2) rapid pathogen proliferation rate
3) Rapid pathogen evolution
4) to distinguish dangerous pathogens from harmless microbes( commensals)

Question 2

what are commensals?

Answer 2

harmless, they prevent other bugs from colonising

Question 3

what are opportunistic pathogens?

Answer 3

don’t infect healthy hosts but produce infections in hospitals to immunodepressed ppl or those with underlying diseases such as cystic fibrosis which favours infection

• eg. Cdiff toxin, H pylori

-commensals - harmless
and Environmental microbes- harmful
- take advantage of incomplete or absent body defences to cause disease.

• more common in hospital patients when resistance may be lowered.

Question 4

what is immunity?

Answer 4

The ability of the human body to tolerate presence of material indigenous to the body ( self) and to eliminate foreign ( non-self) material.

Question 5

what are’ self ‘material?

Answer 5

particles such as proteins and other molecules that are a part of or made by your body, they circulate in your blood or attached to other tissues.

It should not be targeted and destroyed by the immune system.

Non reactivity of the immune system to self particles is called tolerance.

Question 6

what are antigens?

Answer 6

molecules that trigger immune response

Question 7

functions of immune system

Answer 7

1) immunologic recognition detect infection

2)contain and eliminate it via innate or adaptive immunity

3)immune regulation- limit damage to body

4)immunological memory

Question 8

what are the 3 phases of innate and adaptive immunity?

Answer 8

1) Recognition - pathogens and hosts breakdown products

2) activation - inflammation and recruitment of immune cells

3) effector- get rid of the infectious pathogen

Question 9

what are phagocytes?? innate or adaptive?

Answer 9

they recognise and ingest microbes. they are under innate immunity

Question 10

list examples of phagocytes monocytes

Answer 10

macrophages, dendritic

Question 11

list example of phagocytes granulocyte

Answer 11

neutrophils

Question 12

what are lymphocytes?

Answer 12

cells of adaptive immunity, they can recognise and differentiate into B and T lymphocytes

Question 13

what are antigen presenting cells?

Answer 13

they capture antigens and present them to lymphocytes eg. dendrites.

Question 14

what are effector cells?

Answer 14

leukocytes (WBC) that eliminate the microbes and are often lymphocytes/ Natural Killer cells

Question 15

what is the function of a neutrophil?

Answer 15

it ingest and microbes, discharge granules containing microbicidal substances and fight extracellular bacteria+ fungi

Question 16

what do mast cells do?

Answer 16

innate immunity

activated during allergy reactions, defend against helminths- parasitic worm

release factors from granules - histamine and lipid mediator

Question 17

what are basophils?

Answer 17

mini circulating mast cells, release active mediators from granules. activated during allergy reactions.

Question 18

what are eosinophils

Answer 18

bilobed nucleus,

fight helminths,
release major basic protein MBP
pathological in asthma

Question 19

what are Natural Killer cells NK

Answer 19

innate cells.

early protection against virus.

can kill and virally infect tumour cells..

Question 20

what are monocytes ?

Answer 20

they can develop into macrophages or dendritic cells when they migrate out of blood into tissues.
phagocytes bacteria and fungi

Question 21

what targets bacteria and fungi?

Answer 21

monocytes
neutrophils

Question 22

what fights helminths?

Answer 22

eosinophils, mast cells

Question 23

what fights tumour cells?

Answer 23

natural killer

Question 24

what are dendritic cells what do they do?

Answer 24

capture and process materials, migrate to lymphocytes and present to T lymphocyte.

innate cells

Question 25

where are dendritic cells found?

Answer 25

secondary lymphoid organs such as skin, lung, eye, spleen, lymph node and gut.

Question 26

what are B lymphocytes?

Answer 26

adaptive immunity cells
they express B cell receptors on the surface secrete as antibodies.

B cells that secrete antibodies are plasma cells. combats extracellular infections.

Question 27

who produces CD4 and CD8?

Answer 27

T lymphocytes

Question 28

what are CD4 T cells?

Answer 28

helper cells, secrete cytokines to help or suppress other cells.

Question 29

what are CD8 T cells?

Answer 29

cytotoxic cells, they kill infected and cancerous cells.

Question 30

what does T lymphocyte do?

Answer 30

express T cell receptor - CD3, CD4, CD8 on the surface . adaptive immunity cells.

Question 31

who fights intracellular infection?

Answer 31

macrophages and T cells

Question 32

who fights viruses

Answer 32

T cell, antibodies, NK cells

Question 33

who fights extracellular infection?

Answer 33

Antibodies, neutrophils, macrophages

Question 34

what are primary lymphoid organs?

Answer 34

foetal liver, brain marrow and thymus

Question 35

what is the origin of immune cells?

Answer 35

hematopoiesis

Question 36

what are the 3 stages of hematopoeisis

Answer 36

hematopoietic stem cells, progenitor cells, mature cells

Question 37

where does T cell develop?

Answer 37

thymus