B2 - Keeping Healthy

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vaccination helps the body to develop a strong immune system. It also helps to produce specific antibodies.

The antibodies allow the microorganisms to be destroyed before they cause an infection.

Vaccinations arent 100% safe and they can produce side affects

Some vaccines have to be developed regularly because microorganisms mutate (randomly genetically changed) to produce new varieties (strains)

1) A weakened/dead strain of the microorganism is injected. Antigens on the modified microorganism's surface cause the white blood cells to produce specific antibodies.

2) The white blood cells that are capable of quickly producing the specific antibody remain in the bloodstream.

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Infections are caused by microorganisms damaging body cells or producing toxins.

Infections can be treated with drugs called antimicrobials (e.g Antibiotics)

Many antimicrobials kill the microorganism but some just block or slow them down (known as inhibition)

Microorganisms can cause infections which include:

Bacteria - Bubonic Plague, TB and Cystitis (Treated by Antibiotics)

Fungi - Athletes foot, thrush, ringworm ( Treated by anti fungal medicine and antibiotics)

Viruses - Asian Brid Flu, common cold, HIV, measles and small pox. (very difficult to treat) Antibiotics do not work on viruses

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Microorganisms can be found on surfaces, food and drink, water and also in the air that we breathe.

The body provides ideal conditions for microorganisms to grow in because its warm and full of nutriens and moisture.

When they are in your body, harmful microorganisms reproduce rapidly ( double every 20 minutes)

Symptoms of an illness only show when there is a significant amount of the infection. The symptoms are causedd by microorganisms damaging the infected cells and producing toxins in the body.

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Testing new drugs

New drugs are tested for safety and effectiveness before they can be used.

Testing on human cells grown in a lab

Advantages - Shows if drugs are effective, shows if drugs will damage cells, No humans or animals are harmed

Disadvantages- Dont show effects on whole organism, bad ethics some say growing human cells is wrong

Testing on Animals

Advantages - Shows if drugs are affective within body conditions, shows if drugs are safe for the whole body

Disadvantages - Animals can suffer and die, animals may react differently to humans

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Clinical Trials

Clinical trials are carried out on.....

Healthy Volunteers to test for safety

People with the illness to test for safety and effectiveness

Blind Trials - Patients dont know which drugs they're given but the doctor does. If the patient knows, they may give biased information. Its possible the doctors body language could give out clues

Double Blind Trials - Neither the paitient nor the doctor knows which drug is used. Results should be very accurate, due to removing bias. sometimes it is possible to keep what the drug is from the doctor eg. If the patient says the new drug has a different taste.

Open Trials - Both the doctor and patient know that they are using a new treatment. this is when the drug is similar to the one which they are testing against.

Long Term Trials - These are important for ensuring that there are no harmful side effects.

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The Heart and Heart Disease

The heart is ......

a double pump as it pumps the blood from its right side to the lungs and pumps blood from its left side to the rest of the body.

pumps blood to provide the body cells with nutrients and oxygen, and to revove waste products

is made up of muscle cells that need a blood supply from the coronary artery to function properly.

Heart Disease....

is a structual or functional abnormality that can lead to a heart attack

is usually caused by lifestyle and/or genetic factors. It is not caused by an infection

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Blood Pressure

Pulse rate and bloood pressure measurements can be used to monitor the risk of heart disease. Blood pressure is given in two numbers:

- Higher Number (obtained when the heart is contracting)

- Lower Number (obtained when the heart is relaxing)

All measurements that are classed as "normal" are given within a range because people vary in height and weight

High measurements can indicate a high risk of heart disease.

Precautions against Heart Disease

-Regular Exercise (20 Minutes brisk walking everyday)

- not smoking

- Maintaining a healthy weight and keeping a low salt intake

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Blood Vessels

The main blood vessels are arteries, veins and capillaries. Their structure is related to the function.

Arteries - carry blood away from the heart towards the organs. Substances from the blood can't pass through any walls.

An Artery has a thick, elastic, muscular wall to cope with the high pressure in the vessel.

Veins - carry blood from the organs back to the heart. Substances cant pass through vein walls.

A vein has a thinner wall than an artery and has less elastic muscular fibre due to lower pressure in the vessel.

Veins have pocket valves along their length to keep blood flowing in the correct direction

Capillaries- are very narrow vessels that carry blood between arteries and veins. They have walls made of single layer of cells

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Water Balance

Water is imput gained from ..... food and drinks, respiration

Water is output (lost) through ...... sweating, breathing, excreation

The body needs to balance these different inputs and outputs to ensure that there is enough water inside cells for cell activity to take place.

Both hormonal and nervous systems are involved in maintaining the stability of the internal environment of the body. This process is called homeostasis

1) Water levels are monitored by receptor cells in the brain

2) The brain processes the information and coordinates the response to the effector organ.

3) The pituitary gland is an effector which produces the response.

4) This results in a hormone being released to affect the kidneys and the amount of water that is released or retained in the blood.

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Growth of Microorganisms and Choices


Microorganisms can reproduce extreamly quickly.


People can refuse to have a vaccination. But the more who say no the greater chance there is of getting an outbreak of the disease. This is called epidemic.

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Immune Response

If Microorganisms get into your body, the immune system is activated. Two types of white blood cell play a major role in the response.

One acts quick when any microorganism gets into your body

1) Microorganisms invade the body

2) The white blood cell finds the microorganisms and engulfs them.

3) The white blood cell ingests the microorganisms, the microorganisms have been digested and destroyed

Another type of white blood cell makes the antibodies

1) Antigens are markers on the surface of the microorganism

2) The white blood cell becomes sentised to the antigens and produce antibodies

3) The antibodies then lock onto the antigen. this causes the microorganisms to clump together, so that the white blood cells can digest them

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ADH - Anti Diuretic Hormone

The concentration of urine is controlled by a hormone called ADH, which is released into your blood  via the pituitary gland.

When your blood water levels become too high the.....

1) Receptors in your hypothalamus detect a decrease in salt concentration. No stimulus is sent to the pituitary gland.

2) Less ADH is secreted into the blood

3) Your kidneys become less permeable, so less water is reabsorbed

4) Your bladder fills with a large quantity of dilute urine

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ADH Continued

If your blood water levels become too low the opposite happens......

1) Receptors in your hypothalamus detect an increase in salt concentration. A stimulus is sent to the pituitary gland. Thirst is stimulated to encourage drinking.

2) More ADH is secreted into the blood

3) Your kidneys become more permeable, so more water is reabsorbed

4) Your bladder fills with a small quantity of concentrated urine

Drugs such as alcohol and Ectasy affect the product of ADH in different ways:

Alcohol causes ADH to be suppressed, so more water leaves the body in the urine

Ecstasy causes too much ADH to be produced, so too much water remains in the blood. Osmosis causes the water to leave the blood, brain cells then swell and burst.

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