B1 Flashcards
Describe the factors that increase blood pressure.
The factors that increase blood pressure are smoking, eating too much salt, being overweight, stress, drinking too much alcohol regularly, eating a lot of saturated fat.
Describe the factors that decrease blood pressure.
Blood pressure can be reduced by not smoking, reducing salt in the diet, maintaiing a healthy weight, reducing stress, reducing alcohol consumption and saturated fat intake.
Explain how diet can increase the risk of heart disease.
The liver makes cholesterol from saturated fat. Cholesterol is carried in the blood and may be deposited in artery walls, forming fatty plaques. These deposits narrow the arteries and restrict blood flow causing an increased blood pressure.
Recall what proteins, fats and carbohydrates are made from
Proteins are made of amino acids. Fats are made of fatty acids and glycerol. Carbohydrates are made from glucose.
Explain factors that affect how a balanced diet will vary.
A balanced diet is not the same for everyone. It may vary according to age, gender, religion, medical reasons eg diabetes, allergies or personal choice eg vegetarian / vegan.
explain why protein deficiency is linked to developing countries
Protein deficiency is linked to developing countries because they do not eat enough protein. This is because of over population and/or limited food production.
How is EAR (Estimated Average Requirement) of protein calculated?
EAR in g = 0.6 x body mass in kg
How is BMI (Body Mass Index) calculated?
BMI is calculated by dividing a person’s mass in kg by their height in metres, squared.
What are the causes of infectious disease?
The causes of infectious disease are bacteria, viruses, fungi and protazoa.
How do pathogens cause the symptoms of a disease?
Pathogens cause symptoms by invading cells and releasing toxins.
Explain the difference between active immunity and passive immunity.
Active immunity is created when your body makes it’s own antibodies. Passive immunity is created when you receive antibodies rather than make them eg in a vaccination.
Describe how new treatments are tested.
New medical drugs have to be tested to ensure that they work, and are safe, before they can be prescribed. There are three main stages of testing. 1) The drugs are tested using computer models and human cells grown in a laboratory. 2) Drugs that pass the first stage are tested on animals. 3) Drugs that have passed animal tests are used in clinical trials. They are tested on healthy volunteers to check that they are safe. Very low doses of the drug are given to begin with. If there are no problems, further clinical trials are done to find the optimum dose for the drug.
Describe the function of the cornea.
The cornea refracts (bends) light as it enters the eye.
Describe the function of the iris.
The iris controls how much light enters the pupil.
Describe the function of the lens.
The lens focuses light on to the retina.
Describe the function of the retina.
The retina contains light receptors.
Describe the function of the optic nerve.
The optic nerve carries impulses from the eye to the brain.
Explain how short sight is caused.
Someone with short-sightedness can see near objects clearly, but can’t focus properly on distant objects. This is because the lens focuses the sharpest image in front of the retina, instead of on it.
Explain how long sight is caused.
Someone with long-sightedness can see distant objects clearly, but can’t focus properly on near objects. This is because the lens focuses the sharpest image behind the retina, instead of on it.
Describe a reflex arc.
In a simple reflex action : stimulus ? receptor ? sensory neurone ? relay neurone ? motor neurone ? effector
explain the consequences of high blood pressure
High blood pressure can cause: kidney damage, burst blood vessels, strokes.
explain the consequences of low blood pressure
Low blood pressure can cause dizziness, fainting, poor ciculation and organ failure.
explain how a thrombosis can increase the risk of a heart attack
Cholesterol deposits may lead to a thrombosis. A thrombosis in an artery supplying the heart muscle can cause a heart attack.
describe the differences between first and second class proteins
Proteins from plants are ‘second class’ proteins. Proteins from animals are ‘first class’ proteins – they provide all the essential amino acids, including those that the body can’t make.
Explain why the EAR results may vary
A growing teenager will need more protein in their diet than an adult with the same body mass. Pregnant women will also need more protein in their diet, as will new mothers who are breast feeding their baby.
Explain why each pathogen needs specific antibodies
Each pathogen needs specific antibodies because each type of antibody has has a particular shape and can lock on to a particular antigen.
Explain the process of immunisation.
Vaccination involves putting a small amount of an inactive form of a pathogen, or dead pathogen, into the body. White blood cells are stimulated to produce antibodies against the pathogen.
What is a double blind trial?
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In a double blind trial neither the doctor or the volunteers know who is receiving the drug or the placebo.
Explain how the eye focuses light.
Light passes through the eyeball to the retina. It is refracted (its rays are bent) by the cornea and lens, so that the light is brought to a focus on the retina.
Explain how long sight can be corrected.
Long sight can be corrected with a converging lens which bends light rays inwards before they enter the eye.
