Infection and Response

a state of physical, mental and social wellbeing

a disease that can be spread from person to person, oftentimes caused by a pathogen (e.g. the common cold, HIV, influenza)

a disease that can’t be be spread from person to person (e.g. cancer)

how a communicable disease can be transmitted (e.g. the bubonic plague was spread from fleas on rats, which came into contact with humans)

through mutuations in their DNA, inherited in their family or lifestyle factors

vena cava, pulmonary artery, pulmonary vein, leftight ventricle, leftight atrium & aorta

Plaque build up in the coronary artery as a result of a high cholesterol diet; this restricts blood flow and oxygen being delivered around the body, which can lead to a heart attack

- a surgical prodecure called a stent is done to widen the walls of the artery
- medications called statins block the enzymes in the liver needed to make cholesterol; this slows down fatty acid build up
- Stents can cause thrombosis but are long lasting and effective
- Statins have to be taken regularly and can cause muscle and joint pain

Plasma, platelets, red and white blood cells

defences that generally fight bacteria but not any specific types

Phagocyosis: comsuming pathogens
Producing anti-toxins: bind and counteract toxins from bacteria
Produce antibodies: proteins that bind to antigens

drugs that treat the symptom

drugs that fight the pathogen

The pre-clinical stage: tested on human cells and tissues first, then on live animals (mammals)
Clinical stage: given to healthy volunteers before sick volunteers; checking for dosage, efficacy, toxicity- finding the optimum dosage

Thalidomide was a failed drug that was suppoused to be for pregnant women, but ended up causing birth defects in the newborn baby; the drug was released without being fully tested on mammals and volunteers

identical copies of one type of antibody; used to identify and treat different diseases

1. An antigen is injected into a mouse
2. The mouse produces lymphocytes; spleen cells which produce them are removed and then fused with cancerous human white blood cells (myeloma cells) which divide infinitely
3. These form hybridoma cells divide and produce millions of monoclonal antibodies

Pregnancy tests and cancer diagnosis, HIV, AIDS, herpes and chlamydia

Benefits: many uses, quick and effective, produces antibodies very quickly, highly specific
Drawbacks: expensive, side effects, ethical issues with using animals, results in organ failure

unicellular eukaryotes; some are parasites which are transferred by a vector

Malaria is an example; it’s spread by mosquitoes and spends most of its life cycle inside the mosquito, mosquitoes pick up the protist from feeding on an infected animal, and then infect other organisms by inserting the protist into the blood vessels of the organism

by stopping mosquitoes from breeding

using insecticides and mosquito nets

through sexual contact or exchanging bodily fluids

they replicate inside our cells and cause our cells to burst; this damage is what makes us unwell

they replicate inside our cells and produce toxins, which makes us feel ill and damage our cells and tissues

1. through its defence system:
- our skin acts as a barrier
- hair and mucus in our nose traps pathogens
- trachea and bronchi secrete mucus to trap pathogens
- cilia in the trachea and bronchi
- hydrochloric acid in the stomach
2. phagocytosis (white blood cells consume pathogens)
3. produce antitoxins and antibodies (antibodies are specific to a certain antigen)

proteins on the surface of the cell

through vaccinations and drugs