The oesophagus is a muscular tube connecting the mouth to the stomach.
It is approximately 30 centimetres long. The muscles in the oesophagus contract in a series of wave-like contractions known as peristalsis, pushing food from the mouth down to the stomach.
It takes approximately 6 seconds for food to travel to the stomach. Liquid travels even quicker.
The liver is one of the largest organs in the human body.
It has many different functions. The liver produces bile to assist the digestion of fat. It also plays vital roles in the detoxification of drugs, vitamin storage, in regulating blood glucose levels and the inactivation of hormones.
The stomach is a muscular sack about the size of a clenched fist.
It can hold up to 5 litres of food. It acts as a storage area for food before it enters the small intestines.
Food remains in the stomach for up to 4 hours whilst it is mixed with gastric juices consisting of acid and enzymes. The acid dissolves the food and kills most bacteria, while the enzymes help to begin the digestive process.
The pancreas creates a juice containing a mixture of enzymes that digest food when released into the small intestine.
The juice acts to neutralise the acidic stomach contents as they enter the small intestine. The pancreas also process several hormones that play important roles in the body.
The small intestine is where the majority of digestion and absorption takes place and where nutrients are absorbed into the blood stream.
It is approximately 7 metres long and 2-3 centimetres wide. The small intestinal wall is lined with finger like projections called villi. These highly folded structures increases the total surface area over which nutrient absorption can occur.
The total surface area of the small intestines when flatted out is equal to that of a doubles tennis court! Enzymes that break down carbohydrates, proteins and fats are released into the small intestines.
A large number of bacteria live in the small intestines. These bacteria play important roles in digestion.
The large intestine is also known as the bowel or colon.
It is approximately 1-1.5 metres in length and 4-5 centimetres wide. Water and minerals are absorbed here as remaining undigested food moves through the large intestine over a period of 12-18 hours.
The highest concentration of bacteria in the digestive system is found here. These bacteria help breakdown the undigested materials to aid digestion and absorption, also producing vitamins B and K that are needed by the body.