An acid is any substance that has a pH of less than 7 that turns blue litmus (a water-soluble dye) red. It reacts with a base (alkaline) to form a salt.
Acid is measured in pH units. A pH of 1 is the most acidic and 14 is the least acidic (therefore it is alkaline or basic). A pH of 7 is neutral. Foods like citrus juice (like lemon or orange) and vinegar are acidic but their pH is not so low as to be unsafe to eat. Acid foods can have a sour taste.
The alimentary canal is the long, stretchy, muscular tube that goes from your mouth to your anus.
Your alimentary canal is very long, (about 8.3 metres!) and it is where the food you eat is digested. It has different areas with different functions: ingestion (where food is taken in by the mouth), digestion (mostly in the stomach and the small intestine), absorption (mostly food in the small intestine and water in the large intestine), and egestion (rectum and anus).
Alveoli are the tiny and very thin air sacs at the end of the tiny branching tubes (the bronchioles) in your lungs. Gases like oxygen and carbon dioxide are exchanged in the alveoli.
An antibody is one of your body’s finest natural defences, part of the second line of defence against disease and attack by micro-organisms.
Antibodies are a type of protein produced by the white blood cells of your immune system. They recognise and fight against the bad micro-organisms they are made for. You have lots of different types of antibody that help to keep you healthy.
Antibiotics are drugs that are used to treat diseases and infections that are caused by other bacteria and some other organisms like parasites and fungi.
The word ‘antibiotic’ means ‘destruction of life’ but don’t worry – each antibiotic will only work against its particular disease or infection.
Some common antibiotics are penicillin or streptomycin. You must always finish any antibiotics given to you by your doctor, even if you begin to feel well. Never take antibiotics that have been given to someone else!
Argon is a gas that makes up 0.93% of the air you breathe!
Argon has the chemical symbol Ar on the periodic table of the elements. It is constantly released into the atmosphere from the earth’s crust where it is produced.
Your arteries are thick muscular stretchy tubes that carry blood away from your heart. This blood carries oxygen and other nutrients away from your heart and gives it to all the cells in your body.
Bacteria are tiny organisms that live all around you, in you and on you! They are so small that you need a microscope to see them!
Most bacteria are harmless, a lot are good for you but a small few can make you sick. Probiotics are a particularly beneficial type of bacteria that help to keep your gut healthy.
The singular form of bacteria – that is one ‘bacteria’!
A bifidobacterium is a type of good bacteria which lives in your large intestine. It helps to fight infection and keep you healthy. GI Jake is a bifidobacterium and one of the friendliest bacteria is your gut! Bifido comes from the word ‘bifidus’ which means ‘split in two. You can see that in the pictures of GI Jake – he has two lobes, like two ears!
Bifidobacteria don’t need oxygen to survive so they are at home in your large intestine. They are one of the largest groups of bacteria that live in your gut. They help with digestion of your food and they are used as Probiotics.
Your bowel is made up mainly of the small and the large intestine. This is where your food is digested. Sometimes the ‘bowel’ includes other parts of your lower digestive system like the rectum. The origin for the word ‘bowel’ is the Latin word for ‘sausage’!
When you have a bowel movement, it means you have passed (or egested) solid waste (also called faeces, a stool or ‘poo’) from your body.
The bronchus is either of the two main branches of the trachea (windpipe) that join your trachea to each of your two lungs. One bronchus leads to your left lung and the other leads to your right lung.
The plural of bronchus is bronchi.
As your bronchi divide into smaller and smaller branches, they become very thin and are called the bronchioles. The bronchioles join your bronchi to your alveoli, which are the air sacs in your lungs.
Calcium is a mineral that keeps your bones and teeth strong and your nerves and heart healthy. Your body can’t make calcium, so you have to eat foods containing calcium, like milk, other dairy products and green leafy vegetables.
It is an extremely important mineral and is found as a basic component of most animals and plants. Calcium is found in the environment, in materials like shells, limestone and coral reefs. It makes up about 3% of the Earth's crust!
Cancer is a disease of the body's cells. Cancer is not just one disease, but a large group of diseases.
Normally, cells divide and multiply to help the body to grow and repair itself. Cancer cells, however, don’t have the ‘switch’ that tells them when they have grown enough so they divide and grow too much. Cancer cells can invade or damage surrounding tissues.
Your capillaries are the smallest blood vessels in your body. They connect arteries to veins. Through this process they carry oxygen and other nutrients in your blood to the cells in your body. Capillaries also allow the removal of waste products, like carbon dioxide, from your cells.
Carbohydrates are sugars and starches that are the most efficient sources of energy for your body. You can find starchy carbohydrates in some of the foods you eat like bread, pasta, rice, potatoes and sugary carbohydrates in fruits and sweet things.
Complex carbohydrates are starchy carbohydrates that take longer to digest and give their energy more slowly.
Simple carbohydrates are sugary carbohydrates like plain sugar or fruit sugars that take less time to digest and give their energy in quick bursts.
Carbon dioxide is a colourless, odourless gas that is a waste product of your breathing. It has a chemical symbol of CO2.
Carbon dioxide makes up 0.03% of the air you breathe. It is also a necessary nutrient for plants and allows them to photosynthesize (produce their food) and make oxygen!
A cell is the basic structural and functional unit of all organisms.
Cells can live as single independent organisms, like bacteria, or they may form colonies. These colonies make up tissues or organs like those in your body.
A single cell has one or more nuclei (the ‘control centre’), various organelles (the different structures within a cell that have a specific function) and a cytoplasm (the ‘filling’ of the cell where the organelles are). The cell is surrounded by a cell membrane which is semi-permeable, that is, it looks solid but allows gases and water to pass through it. The cell multiplies by splitting into two, each new cell an exact copy of the old one.
A chemical is a substance used in chemistry, like acids, alkalis or solvents.
Chyme is the mix of food and acids that comes from your stomach and moves to your small intestine where most digestion occurs.
Your circulatory system is made up of your heart and blood vessels. It moves blood around your body, which provides oxygen and other nutrients to your cells and takes away waste products like carbon dioxide.
A blood clot is blood that has changed from its normal liquid state to a solid state (also called a scab). This process is called coagulation.
Coagulation occurs when your blood forms a clot, changing from its normal liquid state to a solid state (also called a scab).
Your colon is the main part of your large intestine. It runs from the end of the small intestine to the rectum at the end of the digestive system.
There aren’t many nutrients left when the chyme from your small intestine gets to your colon but water is removed and returned to your body – a very important job!
Carnivores (meat-eating animals, including humans) have slightly shorter colons that herbivores (plant-eating animals, like cows). In humans, the colon is usually between 4 to 6 feet long!
A colonoscopy is a medical procedure that allows a doctor to look at a patient’s colon and rectum.
To perform a colonoscopy, a long and flexible tube, called a colonoscope, is inserted into the patient’s anus. The colonoscope has a tiny light and a tiny video camera, connected to a screen, that lets the doctor see the lining of the colon and rectum. The doctor can test for disease (sometimes visible on the surface of the colon or rectal lining) and collect tissue samples for laboratory analysis if necessary.
A commensal is a micro-organism that lives in close contact with your body without causing disease. An adult has about 2 kilograms (that’s 2 bags of sugar!!) in their gut!
Commensals don’t do you any harm; in fact they are very good to have as they help to keep you healthy!
Commensals have a symbiotic relationship with you, that is, one organism (you) is better off but the other (the commensals) remain unchanged. A great example of this is the presence of Probiotics in humans. The Probiotic bacteria are not affected by being inside you, but you benefit because the Probiotic helps to fight disease and keep you healthy!
Commensals are very selective about where they live! A commensal that is good for you may actually cause disease in another organism!
The con-ju-gated lin-o-le-ic acids (CLA) are found naturally in the meat and dairy projects of ruminant animals (ruminants are animals that ‘chew the cud’ like cattle, sheep and goats).
Meat and dairy products containing CLA have been shown to be beneficial to human health by stimulating the immune system and improving the health of the human gut.
If you are constipated, you have less bowel movements than you would normally; the amount of faeces you pass is small, hard and quite difficult or painful to pass.
You can help to avoid constipation by eating lots of high-fibre foods like fruit and vegetables, drinking lots of water and taking regular exercise.
To consume food or liquids simply means to eat or drink.
Your diaphragm is a thin layer of muscle, shaped like a dome, which separates your chest cavity from your abdomen. You use your diaphragm when you breathe - it helps to expand and contract your chest cavity so your lungs can inflate and deflate.
If you have diarrhoea, you have more frequent bowel movements than you would normally have and the faeces are loose or watery.
The word diarrhoea comes from an ancient Greek word meaning ‘leakage’ or ‘to run or flow through’!
The digestive tract is the long, stretchy, muscular tube that goes from your mouth to your anus.
Your digestive tract is very long, (about 8.3 metres!) and it is where the food you eat is digested. It has different areas with different functions: ingestion (where food is taken in by the mouth), digestion (mostly in the stomach and the small intestine), absorption (mostly food in the small intestine and water in the large intestine), and egestion (rectum and anus).
Dyspepsia is a name for a group of symptoms of your digestive tract including feeling full, bloating, nausea, heartburn or a gassy feeling in your chest or abdomen. The symptoms are felt during meals or shortly afterward. Usually, indigestion is just a short-lived discomfort that often clears up by itself. Eating too quickly or too much and drinking fizzy drinks can cause indigestion, so chew properly and slow down!
An eating disorder is an illness that causes people to adopt harmful eating habits. Two of the most common eating disorders are anorexia nervosa and bulimia nervosa.
Eating disorders are not usually about food itself, but can be a sign of emotional or psychological issues. They can be very dangerous as poor nutrition that generally accompanies eating disorders can harm organs and lead to serious illness and in some cases, death.
Egestion is the process of removal of solid waste from the body. Egestion occurs from the rectum and anus, at the end of the digestive system.
An endoscopy is a medical procedure that allows a doctor to look at a patient’s alimentary canal.
To perform an endoscopy, a long and flexible tube, called an endoscope, is inserted into a patient’s orifice via the mouth or anus. The endoscope has a tiny light and a tiny video camera, connected to a screen, that lets the doctor see the alimentary canal, colon or other generally inaccessible body cavity. The doctor can test for disease (sometimes visible on the surface of the colon or rectal lining), collect tissue samples for laboratory analysis if necessary or sometimes do minor therapeutic procedures.
The word ‘endoscopy’ is derived from the Greek endon ‘within’ and scopeo ‘examine’.
To exhale means to breathe out.
Your faeces are the solid waste excreted from your digestive system via your anus. Faeces are also called ‘stools’ or ‘poo’.
Your body produces a fever to help fight infection. Fever means your body temperature increases to over 37.8oC (100oF) – almost a full degree (centigrade) higher than normal! A fever means your immune system is activated and your body is fighting infection.
Fibre is found in food like cereals, fruit and vegetables. It is not digested but it is a very important part of the diet. Fibre helps digestion by adding bulk to your solid waste and keeps your bowel functioning normally. Fibre is sometimes known as roughage.
Flatulence is caused by a build-up of air / gas in your intestines. When it builds up to a critical point, it is expelled (sometimes quite noisily).
Most belching (or burping) is caused by swallowing air, particularly when you eat or drink too quickly.
Rectal flatulence (or farting) is caused by excessive gas produced by bacteria in the alimentary canal. Fermentation of food by bacteria (a chemical reaction where the bacteria break down the complex compounds in food - like complex carbohydrates - into simple substances) can produce gases like hydrogen, carbon dioxide and methane!
Some foods are more likely to produce flatulence. These include foods like beans, sprouts and cabbage, some varieties of the onion family and avocados, which all contain compounds called flatogens! You can reduce flatulence by eating food in small bites, chewing properly and drinking plenty of water.
Food poisoning is caused by eating or drinking something that has been contaminated by bacteria and sometimes viruses. The experience can be unpleasant and usually includes vomiting and diarrhoea.
Most people recover quickly from food poisoning but in some cases the symptoms can be very serious and can mean a visit to the hospital. In the very young, the elderly or those who are weakened already by illness or malnutrition, the consequences of food poisoning, such as dehydration from diarrhoea, can be life threatening.
A functional food is one that has had something added to it so it has more health benefits than normal. A good example is yoghurts with added Probiotics or milk with added calcium or vitamins. Functional foods are thought to help to reduce the risk of disease.
All foods have a function and when eaten in adequate amounts and the proper balance, function to promote health and well-being. Natural whole foods like fruits or vegetables are particular beneficial in a balanced, healthy diet.
Fungi are microbes that include yeasts and mushrooms. Fungi are parasites; they get their nutrients from a host, living or dead! Some fungi are good, yeasts are used in bread-making and other food industries and mushrooms are tasty. Other fungi are not so good – they can even cause disease like athletes foot!
The gastrointestinal tract is the long, stretchy, muscular tube that goes from your mouth to your anus.
Your gastrointestinal tract is very long, (about 8.3 metres!) and it is where the food you eat is digested. It has different areas with different functions: ingestion (where food is taken in by the mouth), digestion (mostly in the stomach and the small intestine), absorption (mostly food in the small intestine and water in the large intestine), and egestion (rectum and anus).
The gut is the long, stretchy, muscular tube that goes from your mouth to your anus.
Your gut is very long, (about 8.3 metres!) and it is where the food you eat is digested. It has different areas with different functions: ingestion (where food is taken in by the mouth), digestion (mostly in the stomach and the small intestine), absorption (mostly food in the small intestine and water in the large intestine), and egestion (rectum and anus).
Genomics is the study of genes and their function. It includes working out how many genes an organism has, what the genes do and how they are organised on the genome (which contains all the genetic information of an organism).
A gland is a group of special cells or an organ that makes a substance that is used in a different part of the body to help it to work.
A good example of a gland is the pancreas. The pancreas is a gland that releases insulin so that different cells in the body can use the glucose (type of sugar) you eat for energy.
If a gland stops working properly, it can cause problems. For example, if the pancreas does not produce insulin, diabetes can occur.
A grain is an edible seed from a cereal crop. Most cereal crops are grasses so grains are really grass seeds! They are the most widely grown crop in the world and provide the greatest food energy of all the crops humans eat. Common grains are: oats, wheat, rice, barley and spelt.
Haemoglobin is a protein found in your red blood cells that carries oxygen from the lungs to the cells of your body. Haemoglobin gives red blood cells their colour!
Hepatitis is a disease that is caused by a virus. It causes the liver to become inflamed and can be quite dangerous.
A host in science is an animal or plant that provides all the nourishment and support for a parasite to survive. The host is quite often damaged or made ill by the presence of a parasite.
Your immune system is one of your body’s defensive systems. It is made up of lots of different cells that are always patrolling your body and fighting any bad microbes they find.
Your immune response is simply the activation of your immune system. It responds to an invader and helps to keep you healthy!
To have immunity means that your body is able to resist attack by a particular disease or pathogen (something that causes a disease). You can gain immunity after you have been infected by a pathogen or through vaccination.
Indigestion is a name for a group of symptoms of your digestive tract including feeling full, bloating, nausea, heartburn or a gassy feeling in your chest or abdomen. The symptoms are felt during meals or shortly afterward. Usually, indigestion is just a short-lived discomfort that often clears up by itself. Eating too quickly or too much and drinking fizzy drinks can cause indigestion, so chew properly and slow down!
An infection occurs when anywhere in or on your body is invaded (infected) by a pathogen. The pathogen settles in and multiplies, causing tissue damage and illness. Your body’s defences work very hard to fight infection when it occurs.
Inflammation is your body’s protective response to tissue injury (like a cut) or threat by a pathogen (like infection). Inflammation in an injured or infected area results in reddening, heat, swelling and pain, but only in that area.
Inflammation signals your body’s defence system to send protective agents (cells like Luke O’Cyte!) to the area. Your defences work to destroy the cause of the inflammation, restrict the spread of any infection and begin the healing process.
Ingestion is the process of taking in food and drink into the body. Ingestion occurs at the mouth, at the beginning of the digestive system.
To inhale means to breathe in.
Iron is an essential mineral that you get from your diet in foods like red meat and green leafy vegetables. Iron transports oxygen in your blood (as part of the haemoglobin in your red blood cells) and deficiency causes a condition called anaemia which results in fatigue and poor resistance to infection. The chemical symbol for iron is Fe.
Jaundice is a disease where the skin and the whites of the eyes turn a yellow colour. This happens when bile pigments (called bilirubin, which is yellow) build up in the blood.
Lactic acid bacteria (LAB) are a large group of beneficial bacteria, some of which are found in your digestive system. They are also widely used in the dairy food industry. LAB ferment sugars and are used in the dairy industry to produce foods like yoghurt and cheese.
LAB are very common in nature and they all have similar characteristics. In particular, they all produce lactic acid as an end produce of fermentation.
Lactose intolerance is a condition where the body cannot absorb or digest lactose, a type of sugar found in milk and other dairy products.
Lactose intolerance is caused when the intestines do not have an enzyme called lactase. Lactase is needed to digest the milk sugar lactose. If a person with lactose intolerance eats food containing lactose, very quickly they will suffer cramps, bloating and possibly diarrhoea! These symptoms can be treated using lactase tablets.
Your larynx is the top end of your windpipe and contains your vocal cords. It is sometimes called your ‘voice box’ – as air moves over your stretchy vocal cords, sounds are produced. Your larynx is at the back of your throat and is connected to the trachea (windpipe).
A laxative is a substance that loosens the bowels, making bowel movements easier. It is used to treat constipation but it has to be taken carefully as too much can cause diarrhoea!
The word ‘laxative’ is taken from the Latin word ‘laxare’ which means to ‘open, widen, extend or release’.
Leukocytes are white blood cells, found in your blood, that play a large part in your immune response. Leukocytes recognise and fight invaders to keep you healthy. Luke O’Cyte is one of the main defenders against Pat O’Gen!
Methane is another name for ‘natural gas’ and is found in very tiny amounts in the air you breathe. It is produced in the digestive systems of humans and animals as organic matter is broken down.
A microbe is another word for a micro-organism. It is generally used to describe harmful micro-organisms like bacteria or viruses and quite often just called ‘germs’.
Micro-organisms are organisms that are too small to be seen with the naked eye but are usually visible under a microscope. Microbes include bacteria, viruses, fungi and some types of parasites.
The science of microbiology is used to study micro-organisms, those organisms too small to be seen with the naked eye, and their effect on humans.
Microbiologists use special techniques to grow and study micro-organisms with help from other sciences like genetics and biochemistry.
The word microbiology comes from the Greek words ‘micron’ meaning small and ‘biologia’ meaning ‘studying life’, so microbiology is the study of small life!
Micro-organisms are organisms that are too small to be seen with the naked eye but are usually visible under a microscope. Micro-organisms include bacteria, viruses, fungi and some types of parasites. They are also sometimes called microbes, germs, or bugs.
Minerals are nutrients required by your body to stay healthy. Minerals are only required in tiny amounts and are taken from your diet. Fruit and vegetables are rich in minerals like magnesium and potassium, meat and green vegetables have lots of iron while dairy products have lots of calcium. There are about 25 known minerals required to keep your body healthy.
If you feel nauseous, you can feel queasy and sick in your stomach, like you are about to vomit.
Nausea can be caused by many different things, from overeating, infection, or just am irritation of your stomach lining.
Nitrogen is a gas that makes up about 78% of the air you breathe! It is a very important chemical, necessary for the growth of plants and animals. The chemical symbol for Nitrogen is N.
A nutraceutical is a food or part of a food that is thought to have a beneficial effect on health which can include the prevention or treatment of a disease.
It can also be a pill or capsule that contains the disease-fighting part of foods – for example, the goodness of broccoli in the form of a pill can be eaten instead of eating the broccoli itself!
Nutrients are the food (and drink) substances that you eat that allow your body to grow and develop. The main nutrient groups are: carbohydrates, proteins, fats, vitamins, minerals and water. To take in enough nutrients to keep your body healthy, you need to eat a variety of fresh, healthy food and drink plenty of water every day.
Obesity is a condition of excessive body weight, where body fat is far higher than the healthy body weight. Obesity can lead to serious illness such as diabetes and heart disease. It is becoming a serious public health problem in developed country as more and more people become obese.
Your oesophagus is the long, stretchy, muscular tube that joins your mouth and throat to your stomach at the beginning of your digestive system.
An organism is an individual living thing that has the ability to function independently. Organisms can be uni-cellular (one cell) like a bacterium or multi-cellular (many cells) like animals and plants.
The word organism comes from the Greek word for ‘instrument’ so in the case of biology, an organism is an ‘instrument for life’!
Oxygen is a colourless and odourless gas that makes up about 21% of the air you breathe. Every time you breathe, oxygen travels from your lungs to every cell in your body using your blood and blood vessels (your arteries, capillaries and veins) as a transport system. The chemical symbol for oxygen is O.
A parasite is a plant or animal that cannot live without its host. It needs another living thing to live and grow. The parasite can live on or inside its host and gets all of its food from the host. Parasites usually aren’t very good for their host and can make you very sick.
A pathogen (like Pat O’Gen) is any bacterium, virus or other organism that can cause disease.
Peristalsis is the rippling action of the muscles in your oesophagus that pushes food towards your stomach during digestion.
Peritonitis is an inflammation of a membrane called the peritoneum that lines your abdominal cavity.
Peritonitis usually occurs as a result of an infection, mainly by bacteria. It can also occur when an internal irritant like acid from the stomach or bile from the gall bladder gets where it shouldn’t be when, for example, an appendix bursts.
The pH scale measures how acidic or alkaline a solution is. The pH scale ranges from 1 – 14, where a pH of 7 is neutral, a pH of less than 7 is acidic and a pH of more than 7 is alkaline.
Your platelets are small, irregularly shaped, very sticky components of your blood. Their job is to control bleeding by sticking together and making a clot. This turns into a scab as it dries to protect the injured area as it heals. Once healing is complete, the scab falls off by itself.
Prebiotics are added to food to encourage the growth of beneficial bacteria in the gut over the growth of harmful ones.
Probiotics are live micro-organisms that, when eaten in adequate amounts, have a health benefit.
Probiotic foods contain beneficial bacteria, usually lactobacilli (a member of the Lactic acid bacteria family) or bifidobacteria (like GI Jake) that help to keep your gut healthy. They are commonly found in dairy products like yoghurts.
The word ‘probiotics’ means ‘for life’.
Protein is a major part of your body. It is one of the main components of your cells and information signals, and is used as energy if you run out of carbohydrates or fats. Proteins are essential for your growth and repair of your cells. You can find protein in your diet in meat, fish, eggs and beans.
Your respiratory system is the group of organs that you use to breathe.
Saliva is produced by your mouth, especially when you think you are going to eat something nice (you mouth ‘waters’!). Saliva begins the digestion of food as it contains enzymes that help to break down food as you chew.
Starch is a complex carbohydrate that is found in potatoes, rice, cereals and breads. It is the main energy source for your body. Starches give energy slowly that lasts longer than simple carbohydrates.
Stress is your body’s reaction to any event that needs a response and it is a normal part of life. Stress can be physical like having to run away from danger, psychological like having to take a test or even emotional, like an argument that leaves you angry, frustrated, nervous or upset.
When you are stressed, your body produces chemicals and hormones that prepare your body for action – either flee or fight. Stress becomes a problem when you experience it most or all of the time and it can seriously affect your health. Irritable Bowel Syndrome (IBS) is known to be a stress-related illness that affects the bowels.
Stress can be controlled by doing things that help you to relax, like regular exercise and meditation.
Sugar is a simple carbohydrate and is found in natural foods like fruit (fructose) or processed foods like sweets and soft drinks (sucrose). Sugar gives energy very quickly and only lasts for a short time.
A symbiotic relationship is one between two or more organisms. It is one where one organism is better off but the other remains unchanged.
A great example of a symbiotic relationship is the presence of Probiotics in humans. The Probiotic bacteria are not affected by being inside you, but you benefit because the Probiotic helps to fight disease and keep you healthy!
Your trachea is your windpipe and it joins your mouth and larynx (voice box) to your bronchi of your lungs.
A tumour is a group of abnormally growing cells that have no useful function in the body. The word tumour originally meant ‘swelling’.
Tumours can be of several types. A beginning tumour does not spread from its location and does not cause cancer. A malignant tumour spreads from its location, invades nearby tissues and causes cancer. A metastatic tumour also spreads from its location but to other, distant tissues and causes cancer.
A vaccine is a substance that activates your immune system but doesn’t cause disease.
When you have a vaccination, you are given a microbe or a tiny piece of microbe that is dead or really weak so it doesn’t make you sick. When your immune system meets this tiny piece of microbe in your blood, it makes an antibody to help destroy it. The antibody stays on patrol in your blood so if you meet this microbe again, your body is well prepared to defend you. You are now immune to this microbe and you won’t get sick!
The valves in your veins act like little doors that allow the blood flowing through your veins to travel in one direction, but not the other. Your valves make sure that your blood flows in the right direction all the time.
Your veins are the blood vessels that carry blood towards your heart from the rest of your body. Veins carry blood containing waste products from your cells like carbon dioxide.
A virus is the smallest type of micro-organism that can cause disease.
Viruses have a very simple structure but they cannot survive on their own. They can only make copies of itself (like a photocopier) inside a living host. Viruses cause disease like measles, mumps, rubella and chickenpox and cannot be killed by antibiotics.
Vitamins are a group of essential nutrients that are required for proper growth and good health.
Most vitamins cannot be made by your body so you must get them from the food you eat. You can get vitamins from the fruit, vegetables, grains and cereals in your diet or they are available as supplements. In all, you need all of the 13 known vitamins as deficiency can lead to metabolic and physical disorders.
Vitamins are split into two main groups; the four fat soluble vitamins (A, D, E & K) and the nine water soluble vitamins (B1, B2, B6, niacin, B12, biotin, C (ascorbic acid), folate & pantothenic acid).
When you vomit, the food is expelled from your stomach, through your mouth.
Vomiting is the opposite of peristalsis, the process where your muscles push food down your oesophagus towards your stomach at the beginning of your digestive system.