B1

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How does your heart pump blood around your body?
By relaxing to fill with blood and contracting to squeeze the blood out into the arteries.
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What is blood pressure?
The force of blood per unit area as it flows through your arteries.
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What measurements are blood pressures represented in?
Systolic (Pressure in your arteries when your heart contracts and Diastolic (Pressure in your arteries when your heart relaxes).
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What factors can lead to high blood pressure?
Excess weight, High stress levels, Excess alcohol.
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Why is high blood pressure dangerous in the long term?
Because the blood vessels can weaken and eventually burst.
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What may happen if a blood vessel burts in the brain?
A stroke.
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Low blood pressure means the blood doesn't circulate efficiently, so some parts of the body are deprived of glucose and oxygen. What does this lead to?
Dizziness, fainting, cold hands and feet.
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What factors increase the rate of heart disease?
High blood pressure, Too much salt, High fat diets.
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What is Thrombosis?
Clotting of the blood in a particular part of the circulatory system.
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What is cardiovascular efficiency?
How well your heart copes with aerobic exercise and how quickly it recovers afterwards.
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What do carboyhdrates and fats do?
Provide energy.
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What does protein do?
Growth and repair of tissues (and energy if carbohydrates are in short supply).
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What are fats made up of?
Fatty acids and Glycerol.
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What are carbohydrates stored in the liver as?
Glycogen, or can be converted to fats.
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How do you calculate BMI?
Mass (in kg) / Height (in m^2).
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What are proteins?
Long chains of amino acids.
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What are the two types of amino acids?
Essential and Non - essential.
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What are essential amino acids?
The amino acids that must be taken in by eating food, and cannot be made by your body.
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What are non - essential amino acids?
Amino acids that can be made in your body.
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What are first class proteins?
Proteins from animal origin, e.g. Meat and Fish. Contain all the essential amino acids that can't be made by the body.
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What are second class proteins?
Plant proteins.
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What disease is caused by protein defficiency?
Kwashiorkor.
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How do you calculate Estimated Average Daily Requirement (EAR)?
0.6 x Body Mass (kg).
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What are the causes of non - infectious diseases?
Poor diet - Lack of vitamin C causes scurvy. Organ malfunction - The pancreas stops producing insuling (which causes diabetes). Genetic inheritance. Mutating Cells.
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What is a pathogen?
A disease causing microorganism
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What is a tumour that grows in one place described as?
Benign.
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When cells break off and secondary tumours start to grow in other parts of the body, what is the tumour described as?
Malignant.
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What does benign mean?
A growth or tumour that isn't usually dangerous to health; does not spreak all over the body.
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What does malignant mean?
A tumour that becomes progressively worse, and spreads around the body.
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What is a parasite?
An organism that lives off another organism, without benefitting that organism.
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Name some pathogens?
Fungi, Viruses, Bacteria and Protozoa.
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What type of organism is malaria spread by?
A vector.
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What are the steps of a mosquito giving malaria to the host? (1)
1). Mosquito (the vector) sucks blood from a human (host). 2). If there are malaria parasites in the blood, they mate and move from the mosquito's gut to its salivary glands. 3). The mosquito bites another person and passes the malaria parasites into
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What are the steps of a mosquito giving malaria to the host? (2)
-into- their bloodstream. 4). The malaria parasites move to the liver, where they mature and reproduce. 5.) The new generation malaria parasites migrates to the blood and replicates in red blood cells, bursting them open. This damage leads to malaria
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What are the steps of a mosquito giving malaria to the host? (3)
-malaria- fever and can sometimes result in death.
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What can be used to prevent malaria (to control the vector)?
Sleeping under mosquito nets. Using insect repellents. Insecticide.
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What are the bodies defences against pathogens?
The skin: Acts as a barrier against microorganisms. Blood clots: Prevent microorganisms entering the blood stream. Respiratory system: Lined with cells that produce a sticky, liquid mucus that forms a mucus membrane to trap microorganisms.
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What are the bodies defences against pathogens? (2)
-The- stomach: Produces hydrochloric acid which kills microorganisms in the food we eat.
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What is a toxin?
A poison produced by a living organism.
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What are the two types of white blood cells and how do they deal with the pathogens?
1). By engulfing and digesting pathogens they find in the bloodstream. 2). By making antibodies to attack pathogens. They recognise antigens on surface of pathogen, produce antibodies which lock onto antigens - killing pathogen.
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How does immunisation work?
1). A person is injected with weakened or dead strain of pathogen, it is incapable of multiplying (harmless) 2). Even though pathogen is harmless, the antigens trigger production of specific antibodies by the white blood cells. 3). Long after the
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How does immunisation work? (2)
-pathogen- has been dealt with, the white blood cells remain in the blood (memory cells produced). This means more antibodies can be produced very quickly if the same pathogen is detected again.
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What are the benefits of immunisation?
1). Protects against diseases which could kill or cause disability, e.g. polio, measles. 2). If everybody is vaccinated, this disease can't spread so eventually dies out.
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What are the risks of immunisation?
1). An individual could have a bad reaction to vaccine. 2). No vaccination is 100% safe, but benefits outweigh risks.
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What is passive immunity?
When antibodies are injected into someones body, because the person's immune system cannot produce antibodies to destroy the pathogen quickly enough.
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What happens if doctors over prescribe antibiotics?
All the bacteria in a population are killed off except the resistant ones, which then spread. So antibiotic becomes useless.
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What is an example of a bacteria that has become resistant to most antibiotics?
MRSA.
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How can drugs be tested?
Computer models. Animals. Human tissue. Healthy volunteers and volunteers who have disease.
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What happens in a blind trial?
Volunteers don't know whether they have been given the new drug or the placebo. Eliminates psychological factors, provides fair comparison.
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What happens in a double blind trial?
Neither volunteers nor doctors know which pill has been given. Eliminates all bias from the test.
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What are the two types of nervous system?
Central Nervous System and Peripheral Nervous System.
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What does the nervous system include?
Receptors and Neurones.
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What is a receptor?
Part of nervous system that detects a stimulus; a sense organ, e.g. eyes and ears.
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Give an example of a receptor?
Smell receptors in your nose.
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What is a neurone?
Specialised cell that transmits nerve impulses when stimulated.
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What are the three types of neurone?
Sensory neurones, Relay neurones, Motor neurones.
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Explain a sensory neurone?
Carry nerve impulses from the receptors to your brain.
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Explain a relay neurone?
Make connections between neurones inside your brain and your spinal cord.
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Explain a motor neurone?
Carry nerve impulses from your brain to your muscles and glands.
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How are neurones adapted to their job?
1.) Elongated (long) shape (axon) to make connections from one part of body to another. 2). Insulating sheath to speed up nerve impulse. 3). Dendrites (branched ends) allow a single neurone to act on many muscle fibres.
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What is a synapse?
The small gap between adjacent neurones
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Steps of the synapse?
1). Electrical impulse travels down neurone until it reaches synapse (gap). 2). A transmitter substance diffuses across synapse. 3). Transmitter binds with receptor molecules on next neurone, causing electrical impulse to be initated in that neurone.
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How does the synapse message go?
Neurone A (Electrical Message ) ----> Synapse (Chemical Message) ----> Neurone B (Electrical Message).
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What are the two types of actions?
Voluntary and Reflex.
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What are voluntary actions?
Actions under conscious control of your brain (you decide how to react).
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What are reflex actions?
Involuntary responses that bypass brain to give fast automatic responses to a stimulus, to protect your body from harm.
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What are some examples of reflex actions?
Knee jerk reaction, Pupil reflex (automatically controlling light entering eye).
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What are the parts of the eye?
Iris, Lens, Cornea, Pupil, Retina, Optic Nerve, Ciliary muscle, Suspensory Ligament.
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What does your iris do (coloured part of eye) ?
Controls amount of light that is entering your eye.
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What does your cornea do?
Refracts rays of light.
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What does your lens do?
Focuses light onto the retina so the rays converge at a single point and produce a clear image on your retina.
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What is the retina?
Back part of eye, containing light sensitive cells / receptors.
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What does the optic nerve do?
Transports the nerve impulses to brain.
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What is the lens?
Clear, flexible bag of fluid surrounded by circular ciliary muscles that change shape of lens.
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What do suspensory ligaments do?
Attach the lens to ciliary muscles.
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What happens when receiving light rays from a near object?
Ciliary muscles contract, Suspensory ligament relaxes, Lens is short and fat to refract light a lot.
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What happens when receiving light rays from a distant object?
Ciliary muscles relax, Suspensory Ligament contracts, Lens is long and thin because light only needs to be refracted a little.
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What are some common eye defects?
Long sighted, Short sighted and red-green colour blindness.
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How can long sight be corrected?
By wearing a convex lens.
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How can short sight be corrected?
By wearing a concave lens.
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What are the two types of vision?
Binocular and Monocular.
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What is binocular vision?
Eyes positioned close together on front of head. Each eye has limited field of view. Can judge distance and speed accurately. Found on humans and predators.
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What is monocular vision?
Eyes positioned on either side of head. Each eye has wide field of view (can see behind and in front). Hard to judge distance and speed. Found on prey.
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What is a stimulant?
Chemical that increases brain activity. Leads to feeling of alertness.
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What is a depressant?
Chemical that decreases brain activity, making you feel tired. Slows down your reactions.
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How does a stimulant act on a snynapse?
Cause more neuro-transmitters to cross synapse. This speeds up the nervous impulses.
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How does a depressant act on a synapse?
Bind with receptor molecules in membrane of next neurone, blocking transmission of impulse. Slows everything down.
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What are the short term effects of drinking alcohol?
Lack of balance and muscle control, Blurred vision and slurred speech.
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What are the long term effects of drinking alcohol?
Liver damage (liver working very hard to remove toxic alcohol from body), Brain damage due to dehydration.
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Why does alcohol cause liver damage?
Because when the ezymes in the liver break down alcohol, the products are toxic and cause liver damage.
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What is a common disease amongst heavy drinkers?
Cirrhosis.
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What are carcinogens?
Cancer-causing chemicals.
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What is homeostasis?
Maintaing a constant internal body temperature (37 degrees).
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Why must your body stay at around 37 degrees?
Because enzymes work best at this temperature.
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What is used to maintain your body temperature?
Vasodilation.
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What is vasodilation?
When the blood vessels close to the skins surface widen to transfer heat to the enviroment.
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What is vasoconstriction?
When the blood vessels near the skins surface become narrow to reduce heat loss as much as possible.
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What are hormones?
A chemical that acts as a messenger.
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What do hormones do?
Travel around the body through the blood stream from organ to organ.
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What gland are hormones secreted from?
Endocrine gland.
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What is insulin?
A hormone produced by the pancreas which contains blood glucose.
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How is type 1 diabetes caused?
When pancreas fails to produce insulin.
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How does insulin work?
Regulates blood sugar levels by converting excess glucose in blood to glycogen in liver.
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What is an auxin?
Hormone responsible for growth in plants.
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Where is auxin made?
In the shoot tip.
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What happens when light shines onto a shoot?
1). Hormones in direct sunlight destroyed. 2). Hormones on side with shade continute to function, causing cells to elongate. 3). Shoot bends towards light.
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What is variation?
Differences between individuals of same species.
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What is a chromosome?
Coil of DNA made up of genes.
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What is a gene?
Small section of DNA that determines particular characteristic.
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What is an allele?
Variant form of a gene.
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What is homozygous?
To have the same alleles in a gene pair.
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What is heterozygous?
To have different alleles in a gene pair.
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What is a genotype?
Genetic make-up of an individual. Usually given by letters e.g. Bb.
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What is a phenotype?
Outward expression of a gene, e.g. blue eyes.
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What does inherited mean?
Receiving genes or characteristics from a parent.
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Other cards in this set

Card 2

Front

What is blood pressure?

Back

The force of blood per unit area as it flows through your arteries.

Card 3

Front

What measurements are blood pressures represented in?

Back

Preview of the front of card 3

Card 4

Front

What factors can lead to high blood pressure?

Back

Preview of the front of card 4

Card 5

Front

Why is high blood pressure dangerous in the long term?

Back

Preview of the front of card 5
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