antigens

Question 1

what are antigens ?

Answer 1

antigens are molecules that generate an immune response

Question 2

what are antigens complementary to ?

Answer 2

antigens are complementary to the receptors of the cells that perform an immune response i.e T helper cells

Question 3

where are antigens located ?

Answer 3

antigens are located on the surface of all cells including cells in the human body

Question 4

what are foreign antigens ?

Answer 4

antigens that belong to cells not usually found in the body

Question 5

what do foreign antigens do ?

Answer 5

stimulate the immune system

Question 6

what are 3 examples of things that have foreign antigens ?

Answer 6

-pathogens
- toxins
- cancerous cells

Question 7

what kind of response is phagocytosis ?

Answer 7

a cellular response which is non-specific

Question 8

what kind of cells are also a part of the cellular response ?

Answer 8

T-cells

Question 9

what are T-helper cells activated by ?

Answer 9

T-helper cells are activated by specific antigens that are complementary to receptors

Question 10

how do T- helper cells respond ?

Answer 10

by producing cytokines

Question 11

what are cytokines ?

Answer 11

chemicals that activate other cells of the immune system
- which also attract cells of the immune system which increases the immune response

Question 12

what is the humoral response to do with ?

Answer 12

antibodies

Question 13

how long do B memory cells approximately last ?

Answer 13

5 years

Question 14

explain the humoral response ?

Answer 14

B-cells are activated by cytokines and complementary antigens
- activated B-cells undergo mitosis and differentiation which is called clonal selection
- some B-cells become B plasma cells that make antibodies and some cells become B memory cells that last up to 5 years in the blood

Question 15

where are all lymphocytes made ?

Answer 15

in the bone marrow

Question 16

where do t-cells mature?

Answer 16

in the thymus

Question 17

what does APC stand for ?

Answer 17

antigen presenting cell

Question 18

what are APC ?

Answer 18

any cell that presents a non-self antigen on its cell surface membrane

Question 19

what will T-cells only respond to ?

Answer 19

T-cells will only respond to antigens which are presented on the APC and not antigens that are detached from cells and within body fluids i.e blood

Question 20

what can T-helper cells differentiate into ?

Answer 20

-some remain as T cells and activate B cells
-some stimulate macrophages to peform more phagocytosis
-some become memory cells for that shaped antigen
-some become cytotoxic T cells

Question 21

what do cytotoxic T cells do ?

Answer 21

cytotoxic T-cells destroy abnormal or infected cells by releasing a protein called perforin which embeds into cell membranes and makes a pore so that any substances can enter or leave the cell which causes cell death

Question 22

where are cytotoxic t cells most common ?

Answer 22

in viral infections because viruses infect body cells

Question 23

at is meant by active immunity ?

Answer 23

when you have been previously exposed to a pathogen so that when you get exposed again large numbers of antibodies can be produced so rapidly that the pathogen is destroyed before any symptoms occur