Health and disease, Year 10: heart disease, risk factors and cancer

Less blood reaches the heart muscle, so it gets too little oxygen

HintAsk what those particular arteries supply, and what a narrower pipe delivers.

The whyThe coronary arteries supply the heart muscle itself. Narrowing reduces the flow, and muscle that is short of oxygen cannot respire enough to keep contracting properly. A complete blockage can cause a heart attack.

A stent

HintA short word of five letters that begins like "stretch".

The whyA stent is pushed into place on a tiny balloon, which is inflated to widen the artery. The stent stays behind to hold it open. It works at once, but it needs an operation and the artery can narrow again.

statins

HintThe name begins like "station".

The whyThese drugs are taken as tablets, usually for life. They need no operation, but they have to be taken regularly, they do not work at once, and some people get side effects.

Some blood flows backwards, so the heart pumps less efficiently

HintRemember what a valve is there to prevent.

The whyValves keep blood moving one way. If one leaks, part of each beat is wasted pushing blood back the way it came, so the heart has to work harder. A valve can also stiffen and fail to open fully. Faulty valves can be replaced with biological or mechanical ones.

To keep the patient alive while waiting for a transplant (or to let the heart rest and recover)

HintDonor organs are scarce, and the wait for one can be long.

The whyA donor heart has to be a suitable match and may not be available for months. An artificial heart can take over the pumping in the meantime. It carries risks, such as blood clots and infection.

mental

HintIt concerns the mind.

The whyBeing healthy is more than not having an illness. The definition has two parts, the body and the mind, and each affects the other. Diet, stress and life situations can affect both.

A non-communicable disease

HintAdd a prefix meaning "not" to the word for an illness that spreads.

The whyCommunicable diseases are caused by pathogens and can spread. Non-communicable diseases, such as coronary heart disease and most cancers, cannot be caught from someone else. They are linked to genes, lifestyle and environment.

Their body is less able to destroy pathogens

HintThink what that system normally does when a microorganism gets in.

The whyThe immune system finds and destroys microorganisms that enter the body. If it does not work properly, infections that most people would fight off can take hold. It is one example of how different health problems interact.

Some viruses living in cells can trigger cancer

HintThink of a disease of uncontrolled cell growth.

The whyCertain viruses change the cells they infect so that those cells start to divide out of control. For example, almost all cervical cancers are caused by infection with types of human papillomavirus (HPV), which is why the HPV vaccine is offered at school.

correlation

HintIt starts with the same three letters as "correspond".

The whyA scatter diagram shows whether two variables change together. If one tends to rise as the other rises, there is a positive correlation. A correlation alone does not prove that one causes the other.

A risk factor

HintThe first word means "chance of harm".

The whyA risk factor can be part of a person's lifestyle, such as smoking or lack of exercise, or a substance in their body or environment. It raises the chance of a disease; it does not mean the person will certainly get it.

A causal mechanism: an explanation of how it brings the disease about

HintA link in the data is not enough; they need to know the "how".

The whyMany risk factors are only known from correlations. For some, such as smoking and lung cancer, scientists have shown how the factor does the damage. For others no mechanism has been proven, so they remain linked to the disease but are not shown to cause it.

Through the cost of treatment and the working time lost to illness

HintThink who pays for hospitals, and what happens when people are too ill to do their jobs.

The whyLong-term conditions such as heart disease need years of treatment, which health services pay for. People who are ill, or caring for someone ill, may be unable to work, which costs their families and the wider economy.

Something that can cause cancer

HintThe first part of the word comes from the name of the disease.

The whyCarcinogens damage cells in ways that can lead to uncontrolled division. They include some chemicals, such as those in tobacco smoke, and ionising radiation, such as X-rays and gamma rays.

The harmful substances pass to the unborn baby and can affect its development

HintAsk how a child in the uterus gets everything it receives.

The whySubstances in the mother's blood can cross the placenta into the baby's blood. Smoking is linked to babies being born early and underweight. Alcohol can affect how the baby's brain and body develop.

Changes in the cells lead to uncontrolled growth and division

HintNormally mitosis happens only when and where it is needed.

The whyHealthy cells divide in a controlled way. If changes in a cell remove that control, it keeps dividing and forms a mass of cells called a tumour. Not every tumour is a cancer.

A malignant tumour

HintIt is the opposite of "benign".

The whyMalignant tumours are cancers. Their cells push into the tissue around them, and some break off and are carried elsewhere, where they start new tumours. This spreading is what makes them dangerous.

It stays in one place and does not invade other tissues

HintThink what "spreading" would mean for where the abnormal cells end up.

The whyA benign tumour is a growth of abnormal cells that stays in one area, usually inside a membrane. Because it does not invade or spread, it can often be removed completely. It can still cause harm if it presses on an organ.

Genetic risk factors (inherited in the genes)

HintIt concerns the instructions carried on your chromosomes, which run in families.

The whySome people inherit versions of genes that make certain cancers more likely. This raises their risk; it does not make the cancer certain. Knowing about an inherited risk allows earlier checks.

secondary

HintThe word means "coming after the first".

The whyCells from a malignant tumour can break away, travel in the blood and settle elsewhere, where they divide to form new tumours. This is why cancers are much easier to treat when found early, before they have spread.