AS-Biology Immunity

-Skin; stops pathogens entering.

-Stomache; acid denatures proteins.

Protects the body from pathogens entering and destroying them if they do.

Helps recognise pathogens as 'foreign bodies'.

Destroys them using phagocytes and lymphocytes.

Resists infection by the same pathogens again (immunity due to memory cells).

1. Physical; skin and blood clots.

2. Chemical; mucas, sweat, tears, stomache acid (pH2)

3. Cellular; white blood cells- phagocytes and lymphocytes, symbiotic bacteria

-How the body responds to an invasion by a specific pathogen or antigen.

-Involves the production of both cells and chemicals.

-Depends on the body's ability to recognise 'self' and 'non-self' and antigens.

-The secondary immune response starts quicker than the primary response and is more intense.

-A larger number of antibodies are produced and faster because the antigen is recognised quicker.

-Protein markers found on the outside of pathogens.

-Enable the body to recognise a pathogen that should not be present.

The constant region may bond to phagocytes.

The variable region binds to antigens.

Antibodies are a type of protein.

-Agglutination; clumping together lots of pathogens

-Reduction of mobility (bind to flagella)

-Act as receptors; help phagocytes recognise and engulf pathogens

-Neutralising toxins; bind to the toxins rendering them harmless (these antibodies are called antitoxins)

-Lysis;mantibodies and enzymes rapture cell membrane so bacteria bursts

-B Lymphocytes mature in bone marrow

-T Lymphocytes mature in the thymus gland

-Both B and T Lymphocytes are formed from stem cells in the bone marrow.

-Maturity occurs in the foetus

-Coordinates all specific responses.

-Play a key role in humoral and cell mediated immunity.

-Produce and release cytokines which stimulate macrophages to engulf pathogens, stimulate B Lymphocytes to divide, and activate T cytotoxic cells (T Killer cells).

-Produce their own type of memory cell.

-B Lymphocytes make antibodies which move out of the blood stream and in to the tissue fluid or 'humor'.

-When a pathogen enters the body it stimulates the corresponding specific B Lyphocytes to divide by mitosis and produce clones.

-Some pathogens present several antigens which cause polyclonal activation (more than one type of B cell cloning).

-Only live for a few days.

-Job; produce lots of antibodies.

-Make around 2000 antibodies per second.

-They are there to take immediate action against the pathogen.

- This is known as the immune response when it comes to vaccinations.

-Have a large amount of ER, ribosomes, mitochondria and golgi body.

-Rough ER is where proteins are produced.

-Mitochondria makes lots of ATP- supplying energy.

-Golgi apparatus processes the proteins before they are released.

-Remember invasions and antigens.

-They can survive for many years.

-When they come in to contact with an antigen again they divide rapidly to produce more plasma cells and memory cells.

-They act like a B Lymphocyte which has been activated.

-This is a secondary immune response when it comes to vaccinations.

-Starts quicker than the first response and is more intrense.

-Larger number of antibodies are produced and faster because the antigen is recoginsed qucker.

-Can occur without you realising that you have become infected.

-Starts quicker than the first response and is more intrense.

-Larger number of antibodies are produced and faster because the antigen is recoginsed qucker.

-Can occur without you realising that you have become infected.

- They work or respond to our own cells which have been invaded by pathogens.

- Respond to transported blood, tissues, and organs.

- Known as cell mediated immunity. 

-Macrophages that have engulfed and broken down a pathogen displays the pathogens antigens on it's membrane (antigen-presenting cells).

-Distress signals from invaded cells.

-Kill infected cells;

-Make holes in the cells membrane;

-Using protiens called perforins to do this.

-The holes allow for osmosis into the cell- causing lysis/bursting of the cell.

-This is sacrificing it's own cells to kill the pathogen.

-Produce their own type of memory cell.

-Naturally occuring chemicals made by micro organisms to kill or inhibit growth of other micro organisms.

-Made by bacteria.

-Only work on bateria, not viruses.

Defined as;

Any compound which kills either (bacterial) or severely impedes the growth of bacteria (bacteriostatic).

-Narrow-spectrum; used to treat infections limmited to a few families and types of bacteria.

-Broad-spectrum; useful to treat infections caused by multiple families of bacteria.

-Previously controlled conditions are becoming increasingly common e.g. TB.

-The bacteria responsible for these infections are often antibiotic resistant pathogens.

-Patients not finnishing their course of antibiotics and over prescribing encourages natural sellection of resistant bacteria.

-MRSA (methicillin resistant stophyloccocus aureus).

-Antibiotics are acting as a 'selective pressure', those bacteria which passes resistant gene(s) can often survive exposure to particular antibiotic(s).

-They often pass them on to others via horizontal gene transfer.

-Use only when appropriate.

-Prescription only (globally).

-Avoid use of 'wide spectrum' antibiotics, thest and use narrow spectrum.

-Ensure tha patients complete their course.

-Don't add to animal feed.

-Stop using them to allow resistant strains to decrease.

-Curare (chemical taken from vines in the Amazon).

-Tribes used it to poison the tips of arrows.

-The active ingrediant was sourced and developed to make a drug called D-Tubocurarine (a muscle relaxant).

-Screening genomes of plants and micro organisms can lead to identifying potential medicine compounds in DNA.

-Or DNA profling of people with diseases could be used to tailor specific drugs to treat them- personalised medicine.

-The ability of an organism to resist infection by responding quickly to foreign bodies (antigens on the pathogen).

-You can aquire immuntiy naturally or artificially (immunisation).

-Active; when the body produces it's own antibodies and memory cells.

-Passive; when the body recieves antibodies from somewhere else e.g. infection. This gives immediate immunity which doesn't last long.

-Ring; vaccination used when a new case of a disease is reported. All people in the immediate area are vaccinated.

-Hurd; vaccination of a large number of people at the same time, interrupts the transmission of the disease.

-Global vaccination and survailance.

-80% initially vaccinated (herd folllowed by strategy of ring vaccination).

Success due to;

-Stable virus (same antigen).

-Live vaccine.

-Vaccnine frezze dried (global distribution).

-Sympotoms of disease obvious.

-Easy administration of vaccine.

-Virus doesn't infect animals.

-Epidemic occurs when new cases of a disease during a given persiod, substantially exceed what is 'expected'- so high incidence rate ;

-When a disease is always present within a population or area ;

-E.g. Influenza epidemics have previously occured which is why yearly booster jabs are now available.

-Pandemic is an epidemic which spreads across a large area (world wide).

-E.x. aids, avian flu, swine flu.

-Epidemiologists study the patterns of diseases and factors affecting the spread of diseases.

-Data is collected on the number of people that are ill- morbidity (incidence+prevalence) and the numbers of people who have died- mortality.

-Incidence; the number of new cases in population per time period.

-Prevalence; number of people with a disease during any given time period.

-Mortality; number of people who have died of a certain disease per time period.

-Plant's have evolved a number of ways of defending themselves against pathogens.

-Some of these responses are not passive- they actively react to an attack.

Physical barriers;

-Waxy cuticle on leaves.

-Bark on trees.

-Cellulose cell walls.

-Lignified cell walls.

-Callus formation (like scars).

-When a plant is attacked it produces callose and it is deposited between the:

-cell wall and cell mebrane;

-Sieve plates in the phloem, sealing it off and preventing the spread of pathogens;

-In plasmodesmata, stopping the spred to their neighbouring cell.

-Plant's don't have an immune system but they do use cell signalling to initiate defence measures and communticate to other cells.

-Many plant's produce toxins that kill herbivores, make them ill, or repell them with strong flavours and odours.

Insect repellents- citronell

Insecticides- kill insects upon injestion.

Antibacterial and antifungal- kill and stop from growing; Phenols, Defensins, Gossypol, Lysozomes.