Health and disease - topic 5 (pg 36-49) paper 1 Flashcards
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
pathogen
organism that causes and infectious disease
bacterium
- smaller than human cells
- may release toxins, making us feel ill
- some types invade and destroy body cells
virus
- smaller than bacteria
- take over a body cells DNA, causing the cell to make toxins
- or causing damage when new viruses are released
fungi
- eukaryotic organisms
protist
- eukaryotic organisms
- some free living
- some pathogens
cholera
- bacterium
- watery, pale diarrhoea, lots of
- prevented by boiling water and washing hands
malaria
- protist
- fever, weakness, chills
- prevented by stopping mosquito vectors biting people
HIV/AIDS
- 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
Ebola
- 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
PLANTS
- fungus
- leaf loss
- bark lesions (damage)
- dieback on top of tree
vector
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
STI’s
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
- each pathogen has unique antigens on its surface
- a lymphocyte with an antibody that fits the antigen is activated
- lymphocyte divides producing identical clones
- some lymphocytes produce antibodies which destroy the pathogen. Some create memory lymphocytes stay in the blood ready to respond if the same antigen returns
Antibodies
produced by white blood cells to match antigens on a pathogen, specific for one pathogen type, destroy the pathogen.
immunisation
given a vaccine to prevent illness from a disease
how do vaccines work
- contains antigens from the pathogen, in the form of dead/damaged pathogens (inactive, not harmful)
- lymphocytes produce antibodies and memory lymphocytes against the pathogen
- if the person becomes infected with the real pathogen, memory lymphocytes will give a rapid secondary response, person is unlikely to become ill.
Antibiotics
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.
medicines
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
cancer
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
