biology

pathogens a micro organisms such as:

• viruses 
• bacteria 

these micro organisms can release toxins and damage cells causing illness to the person or animal that they are in.but white blood cells in our body help us recover when we have illnesses by:

• eating/ingesting the pathogen 
• nuetralizing toxins whith antitoxins that they produce 
• killing them with antibodies  

(For more of white blood cells go to card 6)

we are often given vaccines for different illnesses that we might get in the future a vaccine is a:

• weak 
• chemically disabled 
• dead pathogen.

By injecting us with this vaccine our bodies will produce white blood cells to kill the vaccine the white blood cell will create antibodies these antibodies will be stored in the blood on plasma as memory cells so if you ever get the pathogen you your white blod cells will remeber the antibodies and will produce it quicker. 

• bacteria car rapidly reproduce
• bacteria can :
  • damage cells 
  • and produce toxins 

this can make you feel very ill and weak .

• bacteria are really really small the are around 1/100th of 1 of our body cells.
• BACTERIA ARE CELLS

• viruses are 1/1000th of 1 of our cells
• viruses multiply by invading and taking over the hosts cells and using it to make lots of copies of itself. Once enough viruses have been produced the hosts cell will burst projecting the viruses inside. every virus will do this to a cell a this is what causes you to be ill.  
• VIRUSES ARE NOT CELLS 

The first bodily defence is your skin it protects you from pathogens in the air and in water and is one of the most effective and efficient bodily defences. If a pathogen managed to get into the body via your mouth, nose ,eyes ,cuts ect. your body has a number of cunning tricks and traps to stop pathogons making you ill.

The first is scabs if your skin every gets cut it takes a few hours before you see the beginning of a scab. scabs a crated by platelets in the blood steam that help clot the blood in the area where the cut is. if you have a fewer amount of platelets the slower your blood will clot.

If pathogens enter the body via your mouth or your nose they are soon stopped by hairs and mucus down you respiratory tract or in the nose.

If the pathogen survive thought all of that your immune system takes over and commands white blood cells to hunt down via your blood stream and kill the unwanted pathogens.     

phagocytes 

phagocytes or macrophages eat the pathogens or use special enzymes to attack them they can also send messages to lymphocytes( the other type of white blood cell) to help the out.They can easily pass through tissue walls. 

lymphocytes 

lymphocytes carry antibodies when the correct antibody is found the lymphocyte carrying it multiples and creates more proteins called antibodies and antitoxins which attack and kill pathogens and neutralises there toxins.

antibodies

• bind pathogens and damage and destroy them
• they clump them together so that phagocytes can eat them 
• the bind them together and then send messages to other white blood cells to help  

antibiotics are very similar but have 1 key difference

• antibiotic- a substance that kills bacteria and stops growth.FOR INTERNAL USE ONLY
• antibacterial- a substance that kills and stops the growth of bacteria.FOR EXTERNAL USE ONLY

 Now that that is out of the way i can explain antibiotics properly 

• penicillin was the first antibiotic it was discovered by Alexander flemming in 1928 who accidentally contaminated his Petri dish but came back to find that the mould that naturally occurred on it killed the bacteria that was meant to grow on the dish.like most antibiotics penicillin can be synthetically made to make it safer for humans to ingest them. 
• some bacteria can grow to be resistant to certain antibiotics. if a lagre colony of bacteria enter the body and the victim is given antibiotics(A) some of the colony will survive the first wave of antibiotics(A) due to a genetic fluke or mutation and will multiply producing a colony of antibiotic(A) resistant bacteria. doctors will them prescribe a new antibiotic ,antibiotic (B). if the same thing happens in the new colony then there will be a colony resistant to 2 types of antibiotic. a good example of this is MRSA.
• the easiest way to protect yourself from getting a infection is to keep up personal hygiene.in the 19th century ignaz semmelweis saw that doctors never washed there hands during treating different patients when he suggested the idea to doctors he was ridiculed although his ideas were correct.