Health and disease - topic 5 (pg 36-49) paper 1 Flashcards Preview

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what is health

mental wellbeing
social wellbeing
physical wellbeing


communicable diseases

-passed from person to person
- rapid variation in number of cases over time
- cases are often localised
- e.g. malaria, cholera


non-communicable diseases

- not passed between people
- number of cases only changes gradually
- e.g. cancer, heart disease, diabetes



organism that causes and infectious disease



-smaller than human cells
- may release toxins, making us feel ill
- some types invade and destroy body cells



- smaller than bacteria
- take over a body cells DNA, causing the cell to make toxins
- or causing damage when new viruses are released



- eukaryotic organisms



- eukaryotic organisms
- some free living
- some pathogens



- bacterium
- watery, pale diarrhoea, lots of
- prevented by boiling water and washing hands



- protist
- fever, weakness, chills
- prevented by stopping mosquito vectors biting people



- virus
- no symptoms for a long time, initially flu-like
- repeated infections that wouldn't be a problem of the immune system was working properly


Tuberculosis (TB)

- bacterium
- blood speckled mucus (damaged lungs)
- weight loss
- fever
- prevented by isolating infected people, prompt diagnosis and use of antibiotics, preventing of breathing in contaminated air



- virus
- internal bleeding and fever (haemorrhagic fever)
- headaches
- muscle pain
- vomiting and diarrhoea
- prevented by isolating those infected, wear full body coverage when working with infected or dead


stomach ulcers

- bacterium
- inflammation and bleeding in stomach
- prevented by thoroughly cooking food, washing hands


ash die-back Chalara

- fungus
- leaf loss
- bark lesions (damage)
- dieback on top of tree



the protist that causes the spread of a pathogen


How does Ebola work

infects liver cells
infects cells from lining of blood vessels infects white blood cells.
multiplies inside the cell and destroys them



spread by exchange of sexual fluid
common transmission methods of HIV include: unprotected sex with infected partner, sharing needles, from infected mother to foetus, from blood products


reducing or preventing STI's

- using a condom in sex
- screening people
- screening blood
- using sterile needles in blood transfusions
-treating with antibiotics


Physical barriers

prevent pathogens entering the body
- skin is too thick for most pathogens to pass through
- mucus in breathing passages traps pathogens, cilia lining the lungs move mucus out of lungs to the back of the throat


chemical defences

chemicals produced to kill pathogens/make them inactive
- lysozyme enzyme in tears digests pathogen cell walls
- lysosome also present in saliva and mucus
- hydrochloric acid in stomach kills pathogens in food and drink


epithelial cells line

the surface of tubes


immune system

attacks pathogens if the enter the body
1. each pathogen has unique antigens on its surface
2. a lymphocyte with an antibody that fits the antigen is activated
3. lymphocyte divides producing identical clones
4.some lymphocytes produce antibodies which destroy the pathogen. Some create memory lymphocytes stay in the blood ready to respond if the same antigen returns



produced by white blood cells to match antigens on a pathogen, specific for one pathogen type, destroy the pathogen.



given a vaccine to prevent illness from a disease


how do vaccines work

1. contains antigens from the pathogen, in the form of dead/damaged pathogens (inactive, not harmful)
2. lymphocytes produce antibodies and memory lymphocytes against the pathogen
3. if the person becomes infected with the real pathogen, memory lymphocytes will give a rapid secondary response, person is unlikely to become ill.



medicine used to treat bacterial infections. they kill bacteria, specific bacteria are killed by a specific antibiotic. Prevent a lot of deaths, Penicillin is an example.
You must finish antibiotics so the antigen doesn't have time to multiply more


Bacterial resistance

Some bacteria are becoming resistant to antibiotics, the antibiotic is no longer effective. People often stop taking antibiotics too early, this leaves more resistant bacteria alive, which can reproduce and spread.
Bacterial resistance is evidence for evolution.



treat causes or signs of illness, must be extensively tested before it can be prescribed


Development and testing of medicine

Discovery - by screening organisms to see if they produce antibiotics that kill bacteria.
Preclinical testing (lab) - antibiotics are tested in the lab to make sure the medicine doesn't damage cells but damages pathogens inside.
Clinical trials 1 - small dose is given to a healthy volunteer to check the drug is not toxic
Clinical trials 2 - tested on patient diagnosed with illness the drug is designed for. to test whether it works and find the optimum dose


factors affecting risk of developing non-communicable diseases

genes - different alleles may me more prone to mutation or how well nutrients are absorbed
age - older the body, more likely cells may develop mutation which lead to cancer
sex - female hormone oestrogen has protective effects men do not get
environmental - air pollution can cause lung disease, poisons in food and drink damage the body
Lifestyle factors - the way we live, inc. diet, alcohol, smoking and exercise


examples of non-communicable diseases

cardiovascular (heart) disease
lung and liver diseases
dietary diseases


Alcohol in disease

Ethanol is poisonous to cells, when absorbed from the gut it passes first to the liver to be broken down. So liver cells are more likely than other cells to be damaged causing liver diseases


Damage caused by smoking

- nicotine is addictive
- carbon monoxide reduces oxygen levels in the blood
-chemicals in tar are carcinogens that cause cancer, particularly of the mouth and lungs
- substances in cigarettes cause blood vessels to narrow, increasing blood pressure. Can lead to cardiovascular diseases such as a heart attack or stroke


Lifestyle changes to treat cardiovascular diseases

doctors advise the patient to:
- give up smoking
- more exercise
- eat healthier diet
Pros - no side effects, reduce chance of other health conditions, cheapest option
Cons - may take time to work or may not work effectively


Medication to treat cardiovascular disease

if lifestyle changes do not work doctors may prescribe medication such as beta-blockers to reduce blood pressure
Pros - work immediately, easy to do, cheaper and less risky than surgery
Cons - long term and can have side effects, may not work well if taking other medication


Surgery to treat cardiovascular disease

- if an artery becomes narrowed, drop in blood flow damages tissue, a wire frame called a stent is inserted into the narrow part of the artery
- Heart Bypass surgery - new blood vessel is inserted to bypass blocked coronary arteries
- if blood supply to the heart is restricted, not enough blood to the heart muscles for respiration, cells die and person has heart attack
Pros - usually long term
Cons - risk of not recovering after surgery, expensive, more difficult than medication, risk of developing an infection after surgery