P1- Infections and response Flashcards
What are communicable diseases?
Spread/ passed on from one person or animal to another. Caused by four main things: Virus, bacteria, protists and fungi
What are communicable diseases spread by?
Direct contact, contaminated food, by animals, through the air and through dirty water
Name a disease spread by direct physical contact
Chicken pox virus
How is the chicken pox virus spread?
Virus, transferred if you touch pus that comes out of spots caused by chicken pox
Name a disease spread by animals or insects
Malaria
How is malaria spread?
Mosquitoes that take blood caused by malaria from an infected person to someone else who catches it
Name a disease spread by breathing in microbes
Common cold
How is the common cold spread?
Sneezing, when the sneeze virus that causes the cold is carried into the air in mucus in the sneeze
Name a disease spread from contaminated food
Salmonella
How is salmonella spread?
Bacteria in food which is killed when cooked, but if not cooked enough the bacteria is still there
Name a disease spread by dirty water
Cholera
How is cholera spread?
If an infected person goes to the toilet, the bacteria causing cholera passes out in the urine which could mix in with clean water
Name a disease spread by cuts and breaks in the skin
Tetanus
How is tetanus spread?
Caused by bacteria which lives on dirty objects. If an open cut touches bacteria, it will pass through into the body
Name a disease spread by bites by an infected animal
Rabies
How is rabies spread?
If an animal is infected with rabies and it bites you, the virus enters your body through bite cut
What is specific defence?
Distinguish between pathogens, defend against specific pathogens
What is Non-specific defence?
Do not distinguish between pathogens, defend against all pathogens
Examples of non-specific diseases
Physical (barriers), Mechanical (motion), Chemical (chemicals), Biological (organisms)
How do human tears defend against diseases?
Wash out pathogens and contain enzymes
How does the skin defend against diseases?
Tight cell junctions forming a strong barrier, scab over
How does the nose defend against diseases?
Mucus traps microbes
How does the mouth defend against diseases?
Contains ‘good’ bacteria stopping pathogens from growing
How does the trachea and bronchi defend against diseases?
Mucus traps microbes and cilia sweeps them away
How does the stomach defend against diseases?
Produces hydrochloric acid
How does the reproductive system defend against diseases?
Vagina and urethra are acidic
How does the large intestine defend against diseases?
Contains ‘good’ bacteria that stops pathogens from growing
Examples of how communicable diseases can spread in humans
Skin (cuts or animal/insect bites, Stomach (contaminated food and drink), Nose (inhaling pathogens), Trachea/ Bronchi (inhaling pathogens)
What is the immune systems main form of defence?
White blood cells
what are the two types of white blood cells?
phagocytes and lymphocytes
What do phagocytes do?
Engulf microorganisms
What do lymphocytes do?
Produce antibodies and antitoxins
What do microbes have on their surface?
Antigens
What are antigens?
Specific protein on the surface of pathogens which stimulate an immune response
What are antibodies?
Proteins that bind to antigens on the surface of microorganisms
What is phagocytosis?
When a pathogen can be ingested by a phagocyte and destroyed after antibodies bind to the antigen
What are antitoxins?
Chemicals that instead of sticking to the pathogen, stick to the toxins the bacteria is producing and destroy them
What is a vaccine?
A type of medicine that trains the body’s immune system so it can fight diseases it hasn’t come into contact with before
Explain the steps of immunity from a disease
A pathogen enters the body, the pathogen secretes antigens making you feel ill, WBCs of immune system create antibodies that destroy the pathogens, same pathogen tries to infect again, immune system remembers how to make antibodies and pathogen is killed quicker, person is now immune to pathogen and unlikely to get same illness again
What is immune response?
A second exposure to same pathogen causing WBCs to respond quickly to produce lots of relevant antibodies which prevent infection
What does MMR stand for?
Measles, mumps, rubella
What is herd immunity?
Majority of population must be vaccinated against serious diseases, which can reduce chance of people coming in contact with specific pathogen, leading to herd immunity
What is active immunity?
Own antibodies encounter pathogens created by body
What is stage 1 of Drug testing?
Substance thought to make a good drug tested oh human cells and tissues. This is easy and cheap but doesn’t tell them about how the substance would effect an entire organism or a particular organ
What is stage 2 of drug testing?
Drug is tested on live animals. Since humans are mammals, our bodies will react similarly to other mammal animals, telling them a lot about efficacy and toxicity of the substances
What is stage 3 of drug testing?
Give drug to healthy volunteers with a low does to avoid problems. Dose is slowly increased with doctors keeping close eye. Aim is to determine maximum dosage of drug on humans without side effects. If it is ok, it will slowly increase dose looking for ‘optimum dosage’ (efficacy is maximised and toxicity is minimised)
Define efficacy
How well the drug works
Define toxicity
How harmful the drug is
Define dosage
How much of the drug should be given
What does preclinical and clinical testing mean?
Preclinical- Before being tested on humans
Clinical- Tested on humans
What are Monoclonal antibodies
Identical copies of one type of antibody
Step by step of how monoclonal antibodies are made
Mouse injected with specific pathogen and its immune system responds, specific WBCs called B Lymphocytes produce antibodies. Spleen cells which produce the B cells are removed. B cells are combined with tumour cells (which can divide but can’t make antibodies). These are now called Hybridoma cells which can make specific antibodies and are screened to make sure they’re producing the correct one. Hybridoma cells copy themselves and produce antibodies which are called Monoclonal antibodies
Examples of uses of monoclonal antibodies
Pregnancy tests (bind with hormones), detect illness (antibodies bind to antigens, found on pathogens or blood clots on cancer cells), measuring and monitoring (measure/monitor levels of hormones and other chemicals in blood), research (identify specific molecules in a cell/tissue by binding them with fluorescent dye), treating cancer (bound to radioactive substance stopping cells to grow and divide)
Advantages of monoclonal antibodies
Healthy cells aren’t affected, treat wide range of conditions, eventually will be cheaper
Disadvantages of monoclonal antibodies
Expensive at the moment, range of side effects, not widely used, only been developed for 40 years
Examples of Traditional drugs
Heart drug digitalis, penicillin and painkillers
What does heart drug digitalis originate from?
Foxglove
What does painkillers aspirin originate from?
Willow
What does penicillin originate from?
Penicillin mould
Define placebo
A fake version of the drug
Define double-blind trial
Neither patient nor doctor know who has the drug or the placebo
Signs of an ion deficiency
Stunted growth, chlorosis (discolouration)
Characteristics of plant diseases
Stunted growth, spots on leaves, decaying, growths, malformed stems/leaves, discolouration, pests
How to confirm plant diseases?
Website/gardening manual, labs to identify the pathogen, testing kits (using monoclonal antibodies)
Name the type of diseases that affect plants
Tobacco mosaic virus (viral) ,rose black spots (fungal) and alphids (protists)
Characteristics of Tobacco Mosaic virus
Stunted growth, mosaic pattern on leaves, discolouration, can’t photosynthesise
Treatment of Tobacco Mosaic virus
No treatment but can grow TMV resistant crops, have good hygiene
Characteristics of Rose Black spots
Purple/black spots on leaves, turn yellow and drop, plant weakens, reduced photosynthesis, less flowers
Treatment of Rose Black spots
Fungicides
Characteristics of alphids
Penetrate phloem of plants, can carry other diseases
Treatment of alphids
Chemical pesticides
