The Immune System: specific immunity

Question 1

where are T cells produced

Answer 1

bone marrow as immature

Question 2

where do T cells mature

Answer 2

thymus gland, under the influence of thymosin, becomes specialised

Question 3

how do T cells become activated and what happens after

Answer 3

encounter infective connective tissue
travel around the bloodstream only attacking when they recognise the one specific antigen

Question 4

where are B cells produced and matured

Answer 4

bone marrow

Question 5

describe the function of B cells

Answer 5

produce antibodies/immunoglobulins, targets one specific antigen

Question 6

define immunoglobulins

Answer 6

glycoproteins that bind and destroy antigens

Question 7

describe T cells and the cell mediated response

Answer 7

encounter an antigen for the 1st time, they become sensitised to it
cannot detect free antigens in body fluids
so need antigen-presenting cells (APCs) to present the antigen

Question 8

describe an APC

Answer 8

macrophage
engulf and digest antigen
presents antigen on plasma membrane

Question 9

describe a cytotoxic T cell (CD8)

Answer 9

inactivate antigen carrying cells by releasing a toxin
destroy abnormal body cells

Question 10

define abnormal in relation to the immune system

Answer 10

infected or cancerous

Question 11

describe T helper (CD4)

Answer 11

produce cytokines (interleukins/interferons) to support and promote CD8 cells and macrophages
stimulate B cells to produce antibodies

Question 12

describe T regulatory cells

Answer 12

turn off activated T and B cells
limiting the immune response’s potentially damaging effects
immunological tolerance

Question 13

define immunological tolerance

Answer 13

preventing the development of autoimmunity and to protect the fetus during pregnancy

Question 14

describe T memory cells

Answer 14

respond rapidly to followoing encounters with the same antigen

Question 15

describe B cells and the antibody mediated (humoral) immunity

Answer 15

B cells recognise and bind to antigens directly
make antibodies, some released into the bloodstream for distribution but also B cells present antibody on plasma membrane
Helper T cells enable the B cells to enlarge and multiply making 2 B cells: Memory B cells
Plasma cells

Question 16

define plasma cells

Answer 16

produce antibodies, that bind to and destroy the antigen

Question 17

define memory B cells

Answer 17

provides long term immunity for that antigen

Question 18

define antibodies

Answer 18

glycoproteins, in immunoglobulins group
bind to antigens
bind to toxins, neutralising them
activate complement

Question 19

describe the function of IgA

Answer 19

covers epithelial membrane to prevent antigens crossing over
found in breastmilk and saliva

Question 20

describe IgD function

Answer 20

made by B cells
displayed on B cells plasma membrane
antigens bind to activate B cells

Question 21

describe the function of IgE

Answer 21

found on plasma membranes
triggers inflammatory response by binding to an antigen

Question 22

describe IgG function, Grandmas live longer

Answer 22

longest-lived
attacks many different pathogens and crosses the placenta to protect fetus

Question 23

describe the function of IgM, mothers born recently

Answer 23

sign of recent invasion
short lived, appear first
activator of complement system

Question 24

describe the general structure of an antibody

Answer 24

two heavy amino acid chains
two light polypeptide chains
binds between chains is disulphide bonds

Question 25

describe the complement system

Answer 25

system of 20 proteins found in blood and tissues
activated by presence of anitgen-antibody immune complexes
binds to, and damages bacterial cell walls
binds to bacterial cells walls, stimulating phagocytosis
attract phagocytotic cells to the area of infection