Biology 2: Keeping Healthy Flashcards
Pathogens
Harmful organism which invades the body and causes disease
What are microorganisms that cause disease is called
Microorganisms that cause disease and make us feel ill are called pathogens. Pathogens include bacteria and viruses
Give the symptoms and example of diseases caused by bacteria
- symptoms: release of poisons all toxins by the bacteria
* example: bacterial meningitis, tetanus, salmonella, food poisoning, tuberculosis (TB)
Symptoms and examples of diseases caused by viruses
- symptoms: damage to the cells as the viruses reproduce
* examples: influenza (three), the common cold, measles and chickenpox
Toxins
Poison or hazardous substances
Binary fission
Simple cell division
How do bacteria reproduce
- bacteria reproduce by dividing into, which is a type of a sexual reproduction called binary fission
- bacteria reproduce rapidly (this is called exponential growth) in the ideal conditions of the human body
How viruses reproduce
- viruses neither ‘host’ cell to reproduce. They enter the host cell and ‘hijack’ The cells mechanisms for making DNA and proteins, and make copies of themselves
- The copies of the virus are released in very large numbers from the infected cells and go on to infect other cells and other people
Explain Growth of bacteria in culture Graph
- During the initial ‘ Lag phase’ there is no reproduction. The bacteria are copying DNA and proteins within their single cells
- The exponential growth phase is followed by the ‘ stationary phase’ where resources begin to become scarce and bacteria are dying at the same rate as being produced
3 The final ‘’ comes about because bacteria begin to be poisoned by their own toxins
An increase then stays stationary then decreases over time
Name the bodies external defences
Skin, saliva and tears, and acid in the stomach
Name the bodies internal defence
Immune system
Immune system
A body system which acts as a defence against pathogens, such as viruses and bacteria
Properties of white blood cells
White blood cells:
• are made in the bone marrow
• are found as several types: some in golf and I just invading microorganisms while others produce antibodies, which recognise and destroy invading microorganisms
How does the immune system defend the body
White blood cells
White blood cells
Blood so that defend the body against disease
Antigen
Harmful substance that stimulates the production of antibodies in the body
How do white blood cells antibodies and antigens relate
Different white blood cells carry different types of antibody on their surface. An antibody is specific to one antigen
Describe this series of events when invading cells are detected
- The antibody corresponding to an antigen locks onto it
- The white blood cell divides to produce many copies
- Each white blood cell produces many antibody molecules that lock on to invading cells
Describe the different types of antibody
- destroy the invading microorganism
- enable white blood cells to recognise the organism as being foreign
- cause the micro organism to client together, meaning it is easier to engulf white blood cells
Memory cells
White blood cells that form antibodies in response to a particular antigen and retain the ability to make the that antibody should re-exposure to the antigen occur later in life
What Happens after the infection clears up
- After the infection clears up, memory cells remain in the blood stream.
- These can produce large numbers of antibodies very quickly if the micro organism we enters the body again.
- At this point the person said to be immune to that particular pathogen
Immune
When a person has resistant to a particular disease
Vaccine
Weekend microorganism that are given to a person to produce immunity to a particular disease
Vaccination
Medical procedure, usually an injection, that provides immunity to a particular disease
Why do vaccinations undergo
- vaccination programs protect children against diseases that are preventable
- babies and children undergo a course of vaccinations in their first year or so
- some pathogens do not change over time, so the same vaccine can be used against these, year after year
- other pathogens, such as influenza (flu virus), change rapidly, so new vaccines must be developed
Describes what is called as herd immunity
- and epidemic occurs if the disease spreads rapidly through population, for example in the city or country
- to avoid an epidermic, it is necessary to vaccinate a high percentage of the population – this leads to what is called ‘ herd immunity’
- widespread vaccination has eradicated one disease – smallpox – from the world. It is also reduced childhood diseases such as measles, mumps and rubella
- The longer term aim is to eradicate certain diseases all together
Side-effects
Unwanted affects produced by medicine
How do scientists make vaccine safe
- scientists test new vaccines very carefully as there are developed to check for any side-effects
- Side effects can be more severe than some people than in others, because of genetic variation
- no type of medical treatment can ever be completely risk-free (but people often think that the risk is high that it is)
Why do vaccinations need to be checked
- vaccinations are extremely safe, and millions of people have benefited from them
- occasionally, a child may develop a minor adverse reaction (such as a rash or fever). In very rare cases, this reaction can be more serious. Any adverse reactions are recorded and followed up.
- any risks of vaccination must be considered against the benefits. Any vaccine generating an unusual number of adverse reaction will be quickly withdrawn
Antimicrobials
Substance that act to kill bacteria
Antibiotic
Therapeutic drug acting to kill bacteria taken into the body
What are Antimicrobials effective against
Are used to inhibit (low) microorganisms grace. They are effective against bacteria, viruses and fundi
What are antibiotics effective Against
Are effective against bacteria but not against viruses. They allow doctors to treat illnesses caused by bacteria, such as tuberculosis
Resistance
Ability of an organism to resist death/disease/harm, for example resistance may develop in some microorganisms against Antimicrobials
How are microorganisms becoming resistance
• Studies show that some microorganisms are developing resistance to these antimicrobials because of their very wide use
- resistance to antimicrobials means that some strains of bacteria infections are now difficult to control
- antimicrobial-resistant microbes can be a particular problem where Antimicrobials are use frequently, such as hospitals
Give examples of antimicrobials
- antibiotics against bacteria are; antivirals against viruses; antifungals against fungi
- many cleaning products, along with antiseptics and disinfectants
How do I population of microorganisms react to the resistance of antimicrobials
- in a population of microorganisms, some may be resistant to their antimicrobial.
- these will survive the use of antimicrobial and pass on their resistance
- The resistance spreads through the population of microorganisms
Superbugs
Harmful microorganisms that have become resistant to antimicrobials
Because of the overuse of certain antibiotics what 2 things should antibiotics be
- prescribed only four more serious infections, when they are really needed
- completed, so that bacteria causing the infection or killed completely
Mutations
A change in the DNA in a cell
How has antibiotic resistance becomes a huge problem in many hospitals
- Random changes in jeans – call me patience – give some bacteria resistance to antimicrobials
- because of the rapid reproduction mate of bacteria, antimicrobial resistance genes spread through the population
- antibiotic resistance has led to some strains of bacteria that are very difficult to read it out. These include MRSA, which is a problem in many hospitals
Clinical trials
Scientific testing of drugs, vaccines and medical processes
How and where are drugs tested on humans
- Early stages of testing involve human cells grown in the laboratory and animals
- if the drug seems to be effective and safe, it’s is tested on humans in clinical trials. These are carried out on healthy volunteers (to check for safety) and on people with the illness (to test for safety and effectiveness
Control group
In a drugs test trial, the group that receives the placebo allowing researchers to assess whether the drug has an effect in the experimental group
Explain what the different control groups do and the ethical issues
- Receives the existing treatment; another type of control group received a placebo- a tablet or liquid made to look like the drug, but without the active ingredient
- one ethical issue related to a drug trial is that it must not disadvantage the patient. If evidence from the trial suggests the new drug is effective, it is offered straightaway to patients receiving the placebo
Name the different types of control groups
- in and ‘open-label’ trial, both researchers and patients know which drug the patient is receiving
- in a ‘blind’ study, the patient doesn’t know which drug they are receiving but the researcher does
- in a ‘double-blind’ study, neither patient nor researcher knows which drug is being given
Name the reasons why some trials investigate the effects of the drug over a long period of time
- side effects may appear, or increase, over time
* the drug may be become less effective
Circulatory system
A transport system in the body that carries oxygen food and molecules
What is the circulatory system made up of?
Heart
Blood vessels
Blood
What does the blood do
- carries nutrients and oxygen to the body’s cells, and removes and carries waste products from the cells.
- is pumped around the body in blood vessels by the heart
What happens at the heart
The heart is a ‘double pump’- as one half is pumping oxygenated blood from the lungs to the body, the other half is pumping deoxygenated blood from the body to the lungs
What happens at the lungs?
At the lungs, deoxygenated blood absorbs oxygen and gets rid of carbon dioxide
Name the three types of blood vessels
Arteries, capillaries, veins
What do arteries do and their structure
- Transport the blood away from the heart under high pressure
- walls are very thick, elastic and muscular to withstand the pressure
What do the capillaries do and their structure?
- they link the artifices and the veins
* their walls are one cell thick to allow the transfer of substances to and from the cells
What do veins do and what are their structure?
- collect blood and return it to the heart
- walls contain elastic, muscular tissue, but are thinner that those of arteries. The blood is under low pressure and veins have valves to prevent the backflip of blood
Coronary arteries
Blood vessels that carry blood away from the heart
What exactly do the coronary arteries do?
• heart muscles has its own blood supply. The coronary arteries run over the surface of the heart. They provide the heart with the nutrients and oxygen it needs a contract, and remove waste products
How does a heart attack happen
The coronary artery is can become blocked by fatty deposits. This will prevent the heart from receiving the oxygen it needs, leading to an heart-attack
Coronary heart disease (CHD)
When arteries that supply the heart muscle gradually becomes blocked by fatty deposits, preventing the heart from working properly
What main lifestyle factors increase a persons risk of coronary heart disease is (CHD)
- Smoking cigarettes
- Poor diet (a diet high in saturated fat and salt)
- Miss use of drugs (this includes excessive consumption of alcohol)
- Stress
Saturated fat
Oh component of the diet that, when eating in excess, can contribute to the coronary heart disease is and other health problems
Correlation
The link between two factors that shows they are related, but one does not necessarily cause the other; a positive correlation shows that is one variable increases, the other also increases; a negative correlation shows that as one variable increases, the other decreases
How can we reduce CHD
- regular exercise helps prevent against the HD by strengthening heart muscle, providing a healthy body weight and reducing stress
- A healthy diet, low in saturated fat, lowers blood cholesterol and reduces the risk of heart disease
- genetic factors contribute to a person’s chances of having CHD – members of families that have a history of heart disease need to lower the risk factors
Rates of CHD around the world in different countries
- researchers studied the occurrence of heart disease (Epidomiological studies) and genetic factors
- rates of CHD are higher in the industrialised countries such as the UK and the USA, than less industrialised nations for example India and China
How is heart rate measured
By recording pulse rate
Heart rate
The number of heartbeats every minute
Pulse rate and what is it measured in
A measure of the number of times per minute the heart is beating. This is the number of pulses as blood passes through an artery close to the skin(Measured in BMP)
Resting heart rate
A person’s heart rate when in active
What is a normal resting rate for teenagers and adults
- For teenagers the resting heart rate is 70 to 100 bpm
* for adults the resting heart rate is 50 to 70 by
How does the misuse of drugs affect heart
The miss use of drugs, such as nicotine alcohol and ecstasy (MDMA), has a negative effect on health, including the heart rate, and increases the risk of heart disease and heart attack
Blood pressure
The pressure of blood against the walls of the blood vessels
How is blood pressure measured
By recording the pressure of blood on the walls of an artery
How does high blood pressure affect people
- people with consistently high blood pressure have an increased risk of heart disease
- high blood pressure damages the walls of the arteries and make them more likely to develop fatty deposits and get narrower. It also puts a strain on the heart
How is blood pressure and important indicator for health
- blood needs to be under pressure to reach every cell in the body
- high blood pressure increases the chance of strokes and heart attacks
- no blood pressure can cause dizziness and fainting
High blood pressure
blood pressure that is consistently abnormally high
Low blood pressure
Blood pressure that is consistently abnormally low
What is blood pressure measured in
• blood pressure is measured in as millimetres of mercury (mm Hg) and given as to numbers, four example 110/80. The higher value is when the heart is contracting; the lower value is when the heart is relaxed
Epidemiological studies
Studies of the patterns of health and illness in the population
What epidemiological Studies have been carried out on the link between lifestyle factors and heart disease
- on samples of individuals who are bats on as many factors as possible and differ only in the fact or being investigated, for example smokers and non-smokers; drug users and non-drug users
- on individuals chosen at random
- that investigate whether the jeans carried by individuals affect their risk of suffering from particular health problems
Homoeostasis
The way the body keeps a constant internal environment
What must be kept at a very narrow range for the body to function
Temperature, pH and levels of sugar, water and salt
Microorganisms
Very small organism which can only be viewed through a microscope
What does homoeostasis involve
Communication by the nervous and hormonal systems
What does ‘automatic’ control systems have to do with homoeostasis
Response to change bodies ‘automatic’ control systems throughout the body
What are the three parts involved in homoeostasis
- Receptors detect changes in the environment
- Processing centres receive information and determine how the body will respond
- Effectors produce a response
Vasolidate
Increase in the diameter of small blood vessel is near the surface of the body to increase the flow of blood
Negative feedback
Information that causes a reversal in a control system, for example when we get too hot or our body responds to bring a temperature back to normal through sweating and vasolidation
How was water taking in and lost
- water is taken in by drinking and eating and it’s also produced by respiration
- water is lost in your rain and faeces and when we sweat and breathe out
Blood plasma
Yellow liquid in blood, in which blood cells are carried
How does water and blood plasma link
The water content of our bodies must be maintained to keep bodies cells bathed in blood plasma. So, the concentration of water in our cells must be kept constant
What happens if blood plasma is too concentrated or diluted
- if the blood plasma is too concentrated, though cells will lose water
- if the blood plasma is to die loot, the cells will absorb water and burst
How is the concentration of blood plasma affected
By external temperature, exercise level and intake of fluids and salt
Kidneys
Organ in the body that controls water balance
What do the kidneys respond to
To changes in the blood plasma by changing the concentration of year and that is excreted from the body
Excreted
To get rid of waste substances from the body
How do some recreational drugs affects the water balance of the body
- alcohol causes the kidneys to produce a large volume of diluted urine and the body becomes dehydrated
- Ecstasy (MDMA) causes the kidneys to produce very small volumes of concentrated year in. The bodies cells will swell with water
How did kidneys help
Help to balance the levels of water, you rear salts and other chemicals in the blood
Anti-diuretic hormone (ADH)
Hormone which controls reabsorption of water in kidneys (and so water levels in the blood)
Where is Auntie directly, and released from
By the pituitary gland in response to changes in the concentration of blood plasma. The secretion of ADH is controlled by negative feedback
What does ADH act upon
Upon the kidneys to reduce the amount of water lost in the year in
How does alcohol affect The release of ADH
Alcohol suppresses the release of ADH, so less water is reabsorbed by the kidneys
How does ecstasy affect ADH production
Ecstasy increases ADH production, so more water is reabsorbed by the kidneys
