bio - health, disease + development of medicine (5)

• Disease: Any change in the normal function of a part of the body is considered diseased.
• There are two types of diseases: communicable and non-communicable.
• Treatment for this can involve putting stents in – small things that open the artery or by taking a medication called statins that lowers cholesterol which is the fat around the arteries.
• Communicable diseases can be spread from person to person.
• Non-communicable diseases can’t be spread as they are caused by lifestyle or genetics.
• Bacteria multiply very quickly through a process called binary fission and produce toxins that hurt cells.
• Fungi can be single-celled or have a body made of hyphae (thread-like structures) and produce toxins.
• Protists are either parasitic or symbiotic.
• Viruses are a type of pathogen that can cause disease and are made up of genetic material surrounded by a capsid, which is a special protein coat, protecting the genetic material.
• Viruses move into cells and use the biochemistry of it to replicate.
• There are two pathways for viruses to replicate: the lytic pathway and the lysogenic cycle.
• Sexually transmitted diseases are diseases spread through sexual contact (oral/vaginal), carried in bodily fluids, and include HIV.
• Chlamydia is a bacterium that can cause painful urination/pelvic pain and if left untreated, it can lead to infertility.
• HIV increases susceptibility to other infections, severe illness, and death if left untreated.
• The human body has physical and chemical barriers to stop pathogens from entering.
• Physical barriers include the skin, which is the biggest and strongest barrier, and mucus, a sticky substance that traps any pathogens in the back of the throat or the nose.
• Cilia, a structure found in the respiratory system, moves pathogens along.
• Phagocytes engulf pathogens, Lymphocytes produce antibodies.
• Vaccines are used if a disease is serious, they allow a dead or altered form of a disease-causing pathogen that have a specific antigen, into the body so that the body can do the same process.
• Often, we can extract antimicrobial compounds form these plants to use in drugs such as antibiotics.
• Monoclonal antibodies are antibodies that are useful because they’re so specific that they only stick to one thing, and as mentioned they’re released by lymphocytes, but the problem is lymphocytes don’t divide very easily.
• Monoclonal antibodies can be used to find tumour cells, they can be used in pregnancy tests, and they can be used in trials.
• If your body encounters a particular antigen, your lymphocytes might recognise it.
• Memory cells are also created which remain in your bloodstream and produce a quick response if the antigen is encountered again.
• On a pathogen there are antigens, lymphocytes send complimentary antibodies, so they bind to the specific shape of the antigen.
• The immune system destroys pathogens.
• The antibodies make pathogens stick together so it’s easier for phagocytes to engulf them.
• If they do, they clone themselves to make enough antibodies to destroy the pathogen.
• Before a drug can be used to treat an illness, it needs to go through a series of trials: First trial – drug is tested on human tissue to see if it’s doing what it needs to do, Second trial – then it’s tested on live animals, Third trial – the drug is given to humans.
• Non communicable diseases can be caused by obesity, which can be measured with BMI, or smoking, which can cause a fat build-up in the arteries and restrict blood flow.
• Chemical barriers include stomach acid, HCl, which should kill any pathogens in our foods, and lysozyme, an enzyme that breaks down pathogens and is mainly found in our tears.
• Plants also have physical and chemical barriers to fight away pests and pathogens.
• Physical barriers in plants include the cellulose cell wall, which is impermeable to many pathogens, and the waxy cuticle on the surface of the leaf, which is also a barrier to most pathogens.
• Bark, some plants are covered in bark, prevents pathogens from reaching cells and the tissues inside.
• Leaves can often close their stomata to stop pathogens entering.
• Some plants can produce antimicrobial chemicals, proteins, and enzymes.
• Some plants can release compounds that attract larger insects that feed on pests.