week 4: immune responses: part 1 & 2

Question 1

what is a pathogen

Answer 1

agents that cause a disease. infects a wide range of animals, including humans

Question 2

what are the immune defences

Answer 2

innate immunity and acquired immunity

Question 3

describe innate immunity

Answer 3

-already exists in the body and is fast acting.
-non specific

defences include: the skin, protective secretions, cell responses.

Question 4

what are barrier defences?

Answer 4

includes skin and mucus membranes of respiratory, urinary and reproductive tracts.

Question 5

what is a macrophage

Answer 5

circulate in the blood and found in many different tissues. phagocytic cell derived from monocytes.

Question 6

what are Neutrophils

Answer 6

phagocytic cells constituting over half of leukocytes.

Question 7

What are Natural Killer NK cells

Answer 7

non-phagocytic type of lymphocyte.

Question 8

what does a macrophage do

Answer 8

engulf and kill invading microorganisms. induces inflammation.

Question 9

what do neutrophils do

Answer 9

cytoplasm is packed with granules. takes up variety of microorganisms and kills them using granule contents

Question 10

what do Natural Killer (NK) cells do

Answer 10

has a granular cytoplasm recognize and kill abnormal cells. holds viral infection in check before adaptive immune system kicks in.

Question 11

what do NK cells target

Answer 11

body cells which have been infected by a virus.

Question 12

what does the NK cell do after encountering an infected cell

Answer 12

releases proteins called perforins and creates pores in the plasma membrane of the target cell.

Question 13

what do granzymes do and where are they from

Answer 13

from NK cells

break down proteins and in doing so destroy the infected cell and the virus.

Question 14

what are mast cells

Answer 14

connective tissue that releases histamine which triggers blood vessels to dilate and become more permeable.

Question 15

what releases cytokines to enhance immune response

Answer 15

activated macrophages and neutrophils.

Question 16

what orchestrates the allergic response

Answer 16

over stimulation of mast cells.

Question 17

what two cells are part of the acquired immune system

Answer 17

B and T lymphocytes

Question 18

how do B and T lymphocytes bind to antigens?

Answer 18

antigen receptors

Question 19

The small accessible part of an antigen that binds to an antigen receptor is called an _________.

Answer 19

epitope

Question 20

what does the T lymphocyte do

Answer 20

causes death of the infected cell

Question 21

what does the B lymphocyte do

Answer 21

produces antibodies

Question 22

how are antigens exposed to T cells?

Answer 22

through a process called antigen presentation. this involves a protein complex called the major histocompatibility complex. which is expressed on the surface of all cells

Question 23

what is the MHC

Answer 23

the major histocompatibility complex which is expressed on the surface of all cells.

Question 24

what is the difference between MHC class 1 and class 2

Answer 24

all nucleated cells express MHC class.

expression of MHC class 2 is restricted to macrophages and B cells.

Question 25

what is it called when helper T cells stimulate cytotoxic T cells to kill infected body cells

Answer 25

Cell-mediated response.

Question 26

describe the humoral response

Answer 26

-B cells bind to free antigen.
-helper T cells stimulate B cells to proliferate and develop into plasma cells.
-plasma cells secrete a large amount of antibodies.

Question 27

how do antibodies provide defence?

Answer 27

they bind to anigens

Question 28

how do antibodies provide defence?

Answer 28

specific antibodies bind to specific antigens and neutralizes them. They cause the antigen and antibodies to form a large mass, attracting phagocytes to get rid of the waste.

Question 29

what is immunological memory?

Answer 29

the first exposure to a specific antigen represents the primary immune response.

in the secondary immune response, memory cells facilitate a faster more efficient response.