Immune Response To Parasites

Question 1

what are the two types of first line defence

Answer 1

physical barriers, chemical secretion

Question 2

give an example of a physical barrier first line response

Answer 2

skin, nasal hairs

Question 3

what are tears an example of

Answer 3

chemical secretion first line defence

Question 4

what do tears contain that make them suitable for first line defence

Answer 4

antibodies and lysozome enzymes

Question 5

give an example of chemical secretion as part of first line defence

Answer 5

acid secretion, tears, mucus

Question 6

when is the second line of defence triggered

Answer 6

after parasite enters body fluids

Question 7

what are the three second line responses

Answer 7

inflammatory response, phagocytes , natural killer cells

Question 8

what happens in a inflammatory response

Answer 8

injured/infected cells release histamine , causing local blood vessels to dilate, increasing blood flow to that area causing redness and warmth. blood vessels become more permeable and pain is triggered by pressure on nerve endings

Question 9

what are phagocytes

Answer 9

white blood cells that migrate out of the blood and surround, engulf and digest viruses

Question 10

what are natural killer cells

Answer 10

types of white blood cells that detect abnormal cell surface proteins located on virus infected and cancerous cells

Question 11

what do natural killer cells trigger

Answer 11

apoptosis

Question 12

what is apoptois

Answer 12

programmed cell death

Question 13

what are the two specific immune responses to parasites

Answer 13

immune surveillance and lymphocytes

Question 14

what is a clone

Answer 14

a group of about 1000 identical cells made from a common ancestor cell, with just one type of receptor

Question 15

what are the two types of lymphocytes

Answer 15

T lymphocytes and B lymphocytes

Question 16

what are the two roles of t lymphocytes

Answer 16

• stimulate other t lymphocytes and cause b lymphocytes to divide rapidly, - destroy infected cells by triggering apoptosis

Question 17

describe what t lymphocytes do in the immune response to parasites

Answer 17

wait for a phagocyte to become a presenting cell and if they have correct surface receptor they will bind to surface antigens and become activated

Question 18

what happens to T lymphocytes after the pathogen is destroyed

Answer 18

some will remain in circulation as memory cells

Question 19

what is the difference in B lymphocytes compared to T lymphocytes

Answer 19

b lymphocytes can bind directly to antigens

Question 20

what is the role of b lymphocytes

Answer 20

produce antibodies and allow phagocytes to engulf and digest them

Question 21

when does clonal selection occur

Answer 21

when antigen receptor protein binds to a specific antigen

Question 22

what is clonal selection

Answer 22

the activation of a lymphocyte leading to many lymphocytes being made and ready to rapidly divide

Question 23

what is immune surveillance

Answer 23

lymphocytes circulate around body checking for antigens that are non self

Question 24

what is a benefit of immunological memory

Answer 24

produce quicker and more efficient response if parasite returns

Question 25

what are the three ways endoparasites can evade the hosts immune system

Answer 25

mimic host cell antigens, antigenic variation and modify hosts immune system

Question 26

what can a endoparasite do to modify a hosts immune system

Answer 26

suppress T and B lymphocytes responses and degrade antibodies

Question 27

what is antigenic variation

Answer 27

due to very short generation time and high selection pressure, parasites can select a new set of antigen genes each generation allowing them to stay ahead of the immune system

Question 28

what is epidemiology

Answer 28

the study of outbreak and spread of infectious diseases

Question 29

what is herd immunity

Answer 29

if enough members of the population are vaccinated against a parasite, it’s spread is limited

Question 30

what is herd immunity density

Answer 30

the minimum density of resistant hosts required in a population to prevent an outbreak