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neurologyYou need to know

• A pathogen is a microorganism or virus that causes disease, such as a bacterium, virus, protist or fungus.
• Pathogens can spread by direct contact, by contaminated food or water, by droplets in the air, or by vectors such as insects.
• The body’s non-specific defences include intact skin, blood clotting, hairs and mucus in the nose, cilia and mucus in the trachea and bronchi, and hydrochloric acid in the stomach.
• Bacteria can make people ill by multiplying rapidly inside the body and producing toxins that damage tissues.
• Viruses make people ill by entering body cells, reproducing inside them, and causing cell damage when new viruses are released.
• The spread of infectious disease can be reduced by good hygiene, sanitation, isolating infected individuals, destroying vectors, vaccination, and avoiding contact with infected people or animals.
• White blood cells defend the body by engulfing pathogens, producing specific antibodies, and producing antitoxins that neutralise toxins.
• Antibodies are specific because each antibody has a binding site with a shape that is complementary to a particular antigen on a pathogen.
• A vaccine contains a dead, weakened, inactive or fragment of a pathogen that stimulates white blood cells to produce antibodies without causing serious disease.
• Vaccination protects an individual because memory cells remain after the first immune response and produce antibodies rapidly if the same pathogen enters again.
• Herd immunity happens when a high proportion of a population is vaccinated, making it harder for a pathogen to spread to vulnerable people.
• Painkillers relieve the symptoms of disease, such as pain or fever, but they do not kill pathogens.
• Antibiotics treat bacterial infections by killing bacteria or stopping their growth, but they do not kill viruses.
• Antiviral drugs are difficult to develop because viruses live and reproduce inside host cells, so drugs may damage the body’s own cells.
• Antibiotic resistance increases when bacteria with resistance mutations survive antibiotic treatment, reproduce, and pass on the resistance allele or resistance gene.
• The heart drug digitalis was originally extracted from foxgloves, aspirin was developed from chemicals found in willow, and penicillin was discovered from the Penicillium mould.
• New medicines are tested in preclinical testing using cells, tissues and animals, then in clinical trials using healthy volunteers and patients to check toxicity, efficacy and dose.
• A double-blind trial is a clinical trial where neither the patient nor the doctor knows who receives the drug or placebo, reducing bias in the results.
• Health is a state of physical and mental wellbeing, not just the absence of disease.
• Communicable diseases are infectious diseases that can spread between organisms, while non-communicable diseases cannot spread between organisms and include cardiovascular disease, cancer and diabetes.

• Compare the transmission, symptoms and treatment of bacterial, viral, protist and fungal diseases using accurate examples and correct scientific vocabulary.
• Explain an immune response by sequencing pathogen entry, antigen recognition, antibody production, pathogen destruction, memory cell formation and the faster secondary response.
• Evaluate methods to reduce disease transmission by comparing effectiveness, practicality, cost, ethical issues and impact on individuals and populations.
• Evaluate the global use of vaccination by considering herd immunity, disease eradication, access, cost, side effects, public confidence and protection of vulnerable groups.
• Explain the development of antibiotic resistance by linking random mutation, survival during antibiotic treatment, reproduction of resistant bacteria and overuse or misuse of antibiotics.
• Describe the stages of drug discovery and development, including identification of a potential medicine, preclinical tests, clinical trials, placebo comparison, double-blind trials and peer review of data.
• Distinguish correlation from causation by explaining that a correlation is a pattern between variables, while causation requires evidence that one factor directly causes the other.
• Interpret graphs and tables about risk factors by identifying trends, comparing groups, quoting data accurately and recognising that other variables may affect the relationship.
• Evaluate the human and financial costs of non-communicable diseases at local, national and global scales, including effects on patients, families, healthcare systems and economies.
• Compare benign and malignant tumours by explaining that benign tumours stay in one place, while malignant tumours invade surrounding tissues and can spread through the blood or lymph to form secondary tumours.