Communicable Diseases part 2 Flashcards Preview

Biology Module 4 > Communicable Diseases part 2 > Flashcards

Flashcards in Communicable Diseases part 2 Deck (50):

What do the T-helper cells do?

the t-helper cells release cytokines
- these are chemical messengers which are involved in cell signalling
- also contains interleukins
- help stimulate phagocytosis


What do the interleukins do

the interleukins specifically bind to the naïve B-cells in order to stimulate their proliferation
- vary in shape and have to be complementary to the receptors in the B- cell in order to activate it


what do the T-killer cells do

they attack and kill the cells displaying foreign antigens,
produce cytoxins, perforin and granzymes
- the perforin has to be complementary in shape to the antigens displayed on the surface of the cell membrane
- the perforin then bind to the host cell receptors, this opens up pores in its membranes
- the granzymes then enter the cell and cause apoptosis


what do T-regulator cells do

they shut down the immune response after the last pathogen has been eradicated, this prevents autoimmunity
- if this did not happen the lymphocytes would keep attacking our tissues and our own antignes


What are the two types of B cells

plasma and B-memory cells


what do the plasma cells do

the plasma cells release antibodies which our specific to the pathogen,
the shape of the antibodies depends on which B-cell was originally selected these antibodies then bind to the antigens displayed on the pathogen membrane and brings the pathogen closer for phagocytosis, this prevents intracellular pathogens from entering the host cell


What do the T and B memory cell do?

after their production in the primary immune response they remain in the blood for many years, they act as immunological memory.
if they encounter the same type of antigen on a pathogen then they can quickly divide by mitosis
this happens quicker due to the increase in the presence of lymphocytes and increases their concentration


Whats a difference in the secondary immune response compared with the first immune response

don't feel the symptoms in the secondary immune response


What do macrophages produces

they produce monokines these attract neutrophils and stimulate B cells to differentiate and release antibodies


What do many cells release

interferon this inhibits virus replication and stimulates the activity of the T killer cells


What releases interleukins

macrophages and T cells


What do interleukins do

stimulate the clonal expansion and differentiation of T and B cells


How is arteritis caused

is inflammation of the joints
- the antibodies attack the membrane around the joint


What happens in lupus

antibodies attack certain proteins in the nucleus and affected tissue


What are secondary defences

secondary defences are used to combat pathogens which have entered the body, they recognise the pathogens by there antigens on the cell membrane


What are ospins

protein molecules that are non-specific so they can attach to various antigens then bind to the phagocyte and pull it closer


what are the two types of phagocytes

neutrophil and macrophage


describe a neutrophil

multilobed nucleus
manufactured in the bone marrow
short lived
released in large numbers during an infection
engulf and digest pathogens


describe a macrophage

manufactured in bone marrow
travel in blood as monocytes before becoming macrophages in the lymph nodes
larger then neutrophils
round nucleus


describe the process of phagocytosis

an ospin, an antibody, is attached to the surface of a pathogen, they are non-specific in their shape so can bind to a range of pathogens
this brings the pathogen closer to the neutrophil so easier to engulf
the pathogen is enveloped by arms of the cell membrane caused pseudopia
the pseudopia from a circle around the pathogen called a vesticle
a vesticle plus a pathogen forms a phagosome
a lysome which is a sac of lytic enzymes fuse with the phagosome and release the lytic enzymes into the phagosome causing it to become digested and absorbed into the cytoplasm or ejected if toxic
after absorption it produces amino acids and sugar
this is called phagocytosis


How does a macrophage become an antigen presenting cells

macrophages engulf a pathogen but only partially digest the pathogen, the antigens from the cell membrane of the pathogens are saved and moved to a specialised protein complex on the surface of the cell


What is active immunity

Immunity caused by the stimulation of the immune response


What does the antigen presenting cell (APC) do

the APC moves around the body where it comes in to contact with specific cells that can initiate an immune response - t and B lymphocytes, only the T and B cells with correct shape so APC increases contact chance


What does the special protein complex do

this ensures the APC is not mistaken for a foreign cell and attacked by other phagocytes


What is the activation of the T/B cells called

clonal selection


What does the activation of T/B cells lead to

clonal expansion - stimulated by cytokines which stimulate the differentiation and activity of macrophages, B - cells and T-cells


How are phagocytes specialised for their function

receptors on plasma membranes bind to ospin or specific antigen
lobed nucleus
will develop cytotoskelton that helps them change shape to engulf pathogens and move around lysomes
many lysosomes contain lytic enzymes
many mitochondria to release energy from glucose
lots of ribosomes to synthesis enzymes


What is a vaccination

a vaccination provides immunity to specific diseases this is created by exposure to dead or weakened antigenic material


what forms can a vaccination take

whole live microorganisms
- not as harmful as the actual disease but must have similar antigenic structure so they are effective against the real pathogen = smallpox and cowpox
weakened version of the pathogen = measules/TB
dead pathogen = typhoid and cholera
a preparation of the antigens from the pathogen = heptitus B
a toxia which is a harmless version of a pathogen = tetanus


What does a vaccine do

activates an immune system and manufactores antibodies and memory cells to dead or weakened antigenic material


what is a herd vaccination

whole immunity to whole population therefore disease can no longer be spread throughout the population
over 80% has to be vaccinated to prevent those who cannot become immune from getting the disease e.g people with HIV/AIDS


What is a ring vaccination

when a new disease case reported so you vaccinate all of the people in immediate vicinity of the case and you keep going outwards


What might cause an epidemic

pathogens undergo an mutation which can change the shape of their antigens therefore the memory cells no longer have the complementary shape and do not recognise it therefore its unstable and can spread quick


what is an epidemic

when a new strain of pathogen spreads across a continent


What is a pandemic

when a new strain of pathogen spreads across multiple continents


give an example of natural active

immune response provides immunity as a result of an infection


give an example of natural passive

Breastfeeding - antibodies provided in breast milk or placenta, this is useful when immune system is developing


give an example of artificial active

vaccinations = antigens injected therefore immune system response


give an example of artificial passive

antibody injection


What are antigens and what do they do

antignes are moleucles that stimulate an immune response, they are usually proteins or glycoproteins in a plasma membrane


what are antibodies and what do they do

antibodies are immunoglobins these are complex plasma proteins produced by the plasma cells in the immune system, they are released as a response to an infection
there is one type of antibody for every antigen detected


How do toxins work

some antibodies bind to molecules that are released by the pathogens, these toxins and this process makes them harmless


Draw structure of antibody

look at revision card


What is the variable region

different antibodies have different shapes to complement their antigen
different amino acids sequence to their shape therefore they vary in their shape


what is the constant region

same in all antibodies as they have to bind to the receptors on phagocytes and they have to be the same shape


what is the disulphide bridge/bond

holds the polypeptide chains together - they have strong covalent bonds


what is the hinge region

allows the arms to flex and move so can fit more than one antigen


What are opsonins

a group of antibodies that bind to the antigens then they act as binding sites for phagocytic cells so they can easily bind and destroy the pathogen


are opsonins specific or non-specific

some are non-specific and stick to different types of molecules that are not found in the host cells other opsonins are specific and bind to specific antigens


Describe the neutralisation process

an antibody attached to the host cell and makes the antigen useless as it prevents it from entering the host cell before its attacked by phagocytes this is known as neutralisation